Hello, I'm Charles Bell and I'm here to welcome you to this woodturing master class. And to introduce the master himself, Allan Batty. Hello Charles. The subject I've chosen today is the hand cutting of threads on the lathe, free hand. Showing you how to make the threads, putting them together using specially designed chasing tools. So can we have a look at the tool then? This is a pair of match chasing tools, 20 threads to the inch, that's the external thread for cutting the external thread and this is for cutting the internal thread. I take it, they come in other sizes? The problem for the beginner is choice. They go up in 3 threads to the inch right through to 40 I personally in our workshops have 6 threads to the inch through to 30, that allows me to mix and match any thread job that comes into our workshops. I notice there are very short handles for woodturning tools Allan. Again an important principle, unlike a standard turning tool, we work with these close to the body. In front of the body, particularly the external one and this allows me close access to the lathe to the workpiece. What other tools do we need then? There's four tools I will introduce as we work, but I want to introduce them one at a time, explain the tool and how it's used. That's great and this is the project then? Well this isn't the project. What I'm going to do is show you how we make the thread on this first of all I'll cut the female thread, then I'll match the male thread to fit the female thread and we will then actually make a project showing how we use threads in a finished item such as this acorn box here. What I'm actually going to do at this session is show you how to cut first of all the female thread in here and then the external thread and then show you how we fit the two together. And you'll notice there is a line drawn down the side of the box and I've used this to help me to line up the grain and that's the first thing I'm going to do Charles. I'm actually going to strike a line down the box there, so when I come up to line up the grain again, we don't have to identify where the grain is because this doesn't have a lot of grain pattern, unlike your Cocobolos or your more exotic woods. We also need to part this in two and that's a section in where I'm actually going to part through there. This is going to be the lid section and this is going to be the base. First of all we're going to part through now when you use your parting tool here, you go through with half the width of the tool again, so the tool can't jam or bind within the cut. So I'm just going down a series of steps, that is wider than the tool itself, so the tool cannot trap or bind. And the cut. As I said, this is going to be the female part, so first of all I must open up the box to give me access to do the threading section. Now let me introduce this first tool Charles, this is our actual armrest. Traditionally, this was a blade of 7" to 9" inches long, handle was 9" to 15" inches long. Personally this one is a 7" blade and a 14" handle that suits me perfectly. It's got the hook at the end, so whichever tool we've chosen at the time it stops the tool from flying off the end of the armrest and we can pull the armrest in so we can guide the tool to its cutting action. The second tool I want to introduce to you is the cutting tool it's called an inside tool. It's ground down to about an 1/8" of an inch across and ground down its side for cutting, so it'll bore like a drill, but when I pull it across it will cut at the same time, I'm going to put the rest at an angle and it will remain at an angle right throughout the hole cutting operation and including chasing the thread and that will become obvious when we do so I'm just going to push this in like a drill there, then I'm going to sweep it across to the side just to open up the box quickly. There, now all I've done is just roughly opened up the box, no more so as you can see. We've very quickly opened up ready for the next section that we're going to do as a matter of fact, we need to introduce the third tool now, this tool is designed with a hook on the side. It cuts across its main face here and on the side there and I use it to first of all dress up the base of the box and then to cut a groove at the side. That groove is extremely important too and I'll discuss it when we come to it now first of all, I'm just going to level up the base of the box very gently, so we finish it with a very clean face in there. That's it. Now let's level up the bottom of the box now l'm going to pull the tool across gently and when I reach the side, I'm going to allow it to cut in to form a groove there. Now what you'll actually notice with the groove the groove is cut well into the back of the box, but you'll notice that it's curved inside there Charles. And that's left a curve at the bottom of that groove, so when the thread is run, It'll actually run through without leaving a sharp edge. So what's the hook for on the end there? That hook has cut the groove inside there. And what's that for? Very important because when I chase the thread, is to allow me time to remove the chaser without striking the bottom of the box, because if I strike the bottom of the box, the chase stops and it rips the thread out. Now what we've got now, is the groove is cut, the bottom of our box is cut, but I must make sure this is absolutely parallel to the lathe, otherwise the thread will be tapered. Now just by sticking a pencil in there and sighting down the lathe bed, look I can see it's tapered off. So I need to correct that now before we go any further. So it's very easy to correct by using the armrest and the inside tool, and just cut down the back of the box there. And you take a little shaving off the back to parallel that out. And now we can stick the pencil in again and what we can see is we are almost parallel now to our lathe bed. You can see how the pencil is actually parallel to the lathe bed there. This is very important because if the thread is tapered it won't fit together. So we've got two important features, First of all this parallel, secondally we've got the groove cut at the back, but now what we must do we must round this edge over and if we don't round this edge over, as we go on with the chaser the sharp tooth would catch on the edge and it would just stop the tool progressing forward. So I use the armrest and the point tool now, and I'll just roll and round the edge over, to give the tool a nice gentle, soft start. I'm just coming up around the face to clean up the face as well. That's it. Now we're completed, ready for chasing. Now it will become obvious when we use the tool rest in conjunction with the chasing tool instead of working over the rest. If I work over the rest, what happens is as the chase goes in, the chaser takes the least line of resistance and comes off the thread. By working with the armrest with the hook on, what I can actually do is, I can pull the armrest towards me, which keeps the chaser into the thread. Now again, you'll see why I put the rest at an angle now, we need to go in at an angle here and as the chase starts, I take the tool around in an arc as it goes forward. And we'll square it up towards the end. We'll need a little bit more angle with the rest, to get me in there, that's fine. And again a short rest helps here, now I need to go down to a slower speed. So what were you running at before? I was turning at approximately 1,800 or 1,900 RPM, but now we're at a chasing speed and this is very important. Our speeds when we chase a thread must go from a minimum of 150 RPM to a maximum of 500. And by doing so, we are in control. If we go too slow, the thread can end up with a drunken thread. If we go too fast, you'll strip the thread out as we chase. I tend to work at a comfortable speed of about 300 RPM. Using the inside chaser, now the very first time we touch the work is so fine and gentle, that the chaser hardly touches the work. Here it? There now the thread is starting. What you can see is look, there is two or three threads cuts inside there. That's not a problem now, the chaser has a spiral to pick up on and it'll pull itself on as it goes. Now I don't cut with the lead tooth, i'ts very important that we don't cut with the lead tooth. Now as I go down, I'm adding another thread each time look, see how there's one more thead being added each time. And now what I've done, I've reached all the way through, so the thread is now cut on a taper. But now I can cut with the lead tooth because it's got a track to follow. But without that track the chaser would stop dead, but now I can spin the chaser in square to the lathe and start cutting with the lead tooth as we go along. Now I'm using the armrest to just gently pull the chaser back towards me, but when I reach the bottom of the cut, I release with that so it stops the cut taking place and stops it screwing into the back of the box bottom of the box and striping your thread. So there now, just gentle, take your time. There's no rush with this kind of thread. And there's our thread cut. It's a full thread, it's nice and clean, again see the shaving, We want good shavings like that. If you're just getting dust off your chasing tool, it needs sharpening. But now we have our good, clean internal thread cut, ready for matching into our male thread. But you can see the purpose of the groove now Charles. It just gives me a chance to pull the chaser off before we wreck it. So now we can take that out and we can now start with the male thread to match the two together. You'll notice on this one there's a playing part ahead of the thread. That's a spigot that we're going to work to and I'll show you the purpose of that as we go. But before I actually cut the full thread properly, I'm going to show you two ways to chase a thread. This is important that you understand these because there is a couple of ways. I'm just going back to turning speed first. I'm going to cut a groove again to just allow the chaser to be removed from the work before it strikes the base. And that's where we are going to cut the first thread. Now the first way is relatively simple. Take your rest up reasonably close to the work, and with the outside chaser now, what we're actually going to do is come from the corner here and bring the tool around. We don't cut with the lead thread again until the thread's established. This is a very relatively simple way. The tool is going to stay in one plain all the time as it comes around. You need to go back to chasing speed, approximately 300 RPM, and just start there and gently move the chase along. Now you can see the threads being cut now look, notice where the chaser is cutting, it's cutting two or three threads back, and each time I go along it, I add one more thread. Now then, the threads run all the way along. So now we can start to cut with the lead tooth now. Because the lead tooth has a very definite track to follow. But unless the thread has run all along, you mustn't cut with the lead tooth. Again, see those little shavings that indicate that the chaser is ever so sharp. And there's a simple way to chase a thread. And again a good clean thread, but do you see that little escape route which allows the chase to be removed before it reaches the shoulder. That'll strip your thread. That's an easy way, but I'm going to show you another way that we chase threads. It's a little bit more complicated, but it's also much more accurate. And you'll see the reason why. But first of all we must have a way of measuring our thread size, so let me just clean up the face first. What I'm going to do is cut a small spigot to just fit inside the thread. There. Now what you'll notice is, this actually fits inside the thread. This is our guide to cutting an accurately fitting thread, we don't need to use calipers or measurements or dividers or of any gauges. Now all I do now is leave enough wood for a thread. So the spigot is really the same height as the top of the thread. Exactly, that's exactly right. That's exactly where we're going. Now all I'm doing is leaving sufficient wood now for a thread. And that's my spigot there. Now again, I made that little avenue to pull that tool up quickly, so I'm going to use the point tool. The point tool is going to serve two purposes. First it's going to cut a little groove at the back there, that's it there. And then it's going to dress up the face, so the face is all finished in one movement. There. Now you'll notice now the similarity between this, the only difference is There's the playing part which is there, there's our thread and there's our take off point. I must round this edge over again on the thread. Just rounded that over and now I'm going to work in a little more of a complicated way for chasing the external thread. The reason we'd preferred this method, this is a much shorter thread than you'll notice I ran on the outside before And obviously the problem is if I just drag this along and strike the shoulder of it before I can run the thread properly. So I'm going to work in a circular motion now with the rest well back, I'm going to put my finger underneath the rest, my index finger of the left hand supports the tool from underneath and I work in a rotational action like this. To arouse me to run little short quick threads in, every so accurately. Is it safe for your fingers under there? Oh perfectly safe because my fingers are away from the work and I'm supporting the tool just like that. Now what I watch people do is they grip the tool here. Now what they can't do is move the tool in a circle that way. Put the finger on top and that's all you do with your finger and the tool will do the same. Again let's go back to turning speed. The same speed as for the outside speed is what we used for the inside. About 300 rpm. Now here, I'm just going to touch the work gently. You'll just here the chaser touch there. And there's the thread running now look. Again the little rotating action just dropping in. Take your time, don't rush this. There's no rush with thread chasing. And now you can see the thread is developing a treat look. And I can cut with the lead chase or lead tooth now because the thread is cut on a taper. So I can drop in with the lead tooth and come in and cut the thread in a conventional manor. So how do you know when you've got it to the right depth? What I'm looking for is when the chasing tool leaves a line on this spigot. That's the witness mark that I'm down to the top of the other thread, the internal thread. It's not quite there yet, you'll see it in a second. Now there's a witness mark just starting to appear on there, but I'm just taking the taper off the thread now. Now there's a good witness mark appear and you can actually see there where the chase is. Just left a mark on that spigot. So that should indicate now that this should start. And there's our thread just going on. Now what you can see is it's slightly tapered that thread, but I've got a full depth thread. If I continue with the chaser now I'll strip the thread out. So what we do is, we turn it off with a turning tool first, go back to turning speed and put a flat on top of the threads. There. Now that spigot is finished because we've got our determined size, so we can turn that off. But as I turn that off, what you'll notice now is we have a thread coming out very sharp. Now that thread would just crumble in use. So what we're going to do is just round that edge over. There. And now I can finish off the thread, but just before I do, I just want to deepen the groove at the back, just a fraction. That's it. Just clean up that face nice and gentle. And now back to chasing speed. If you've reached this stage and your thread is looking good and you're worried about going in with the lathe running, don't. Just start your lathe and rotate it by hand because the chase will follow the groove now. I prefer to run with the lathe running because it speeds up the process. But you've got to drop in the same thread every time. Little bit of practice. There's an easy way to master this Charles. You buy a ton of boxwood, you lock yourself in your shed for a year and you come out all screwed up. And there we are look, our thread is now running, but truthfully it is only practice. And what you can see now look, we've got a good, clean thread and hopefully the two are mating together. They're still just a fraction tight, I'll just need to ease it. It's just a fraction tight, so we'll take that off now before we go any further. There's no point in spoiling it. Again, see the long stream of shavings coming off? Now just as I reach that shoulder, I must lift the tool off, otherwise if the chaser stops for a split second, your thread is just ripped out. And now what we should have is hopefully, yep. Now you can see the pencil line we struck earlier, you can see they don't meet. So what I need to do is take a bit off one face or the other. I've got a couple of choices now. I can either take it off this face here, or I can take it off this one. The danger is if you take it off this face and if you have two or three shots at it, you're moving away from the thread and you end up with a blank piece. But I prefer to take it off this one, so we're always working back into a thread. Now before I do that, you'll notice there's just a little tiny piece of rubbish just at the back the thread. Don't leave that. Go in with the point tool and we'll just clean that up. Because to me, if you're going to do threads, now notice I went back to speed there? The reason I went back to speed, Iv'e been caught with this before. If I go in with a point tool at this slow speed, it'll pick up on the thread and it'll just rip the thread out. So by going back up to speed, there's less danger of picking up on the thread. There's less danger of striping out your thread by going back to speed. Now then, as I said earlier, I like to take it off this face, rather than this face. So we'll just re-turn that other piece back into the chuck. And we'll identify how much is to come off. When I screw that into there now, we'll see how much there is to go around. And what we can see is, I've got about three quarters of a turn left. So that tells me I've actually got three quarters of a thread to take off this face. Now I can go back to using the scraping tool here Back to turning speed across the face there. All I 'm going to do is take off three quarters of a thread. And try again. There's no substitute for patience here. You just keep going until you get it and don't take too much. Now you can see we're down to less than half a thread to go for the line to come around. These threads, here that squeak? When you polish your threads, that actually goes away. Now I'm just going to take a little bit more off this. Again don't be too ambitious at taking it off. And again, just round over that sharp corner. But you see by working it this way we're actually taking it into a thread, rather than working away from a thread. Just the dust in there. That's fine. Now this should, if we've got this right this time, it should go where it mates together. Right now then, you can see where the line now is approximately three quarters of an inch away. I would leave that at this stage until I'd completed the box, because it might just move around a fraction more as you shape your box. So at that point I'd be satisfied with that. But what I can do now is go into a project and show you how to make a project very quickly, but you've got the principle of threads, but we'll include the threads in the project that we're going to make. Excellent Allan, thank you very much. Just one little point while we're talking, we often want to make threads where we can't use an internal chaser and it's one little valuable point. There's an easy way to overcome the problem. What you'll see is that's a very fine quarter inch thread. The outside chaser did that, but we have no access for the internal chaser for there. So the way the problem was overcome, we actually drilled ant tapped it with an engineers tap like that. That tap actually corresponds with my number twenty chaser. So when the threads are all screwed together, what we finish up with is a very nice, tidy little knob that's finished like that. But it's screwed in into any situation you want to place it. So you used a piece of boxwood there, which obviously takes a thread very well? There must be timbers that you can't cut a thread on? There's many timbers that won't take threads. For example, soft woods won't take threads, so it's going to be a dense hardwood such as African Blackwood, Boxwood as you saw is an obvious one. So what do you do with a piece that you need to cut a thread in, but you can't because of the nature of the timber? The one thing I learned in the trade, there's always a solution to the problem and is one of the solutions that overcame the problem. For example, on this walking cane we have a thread on the end which shows what we've done. We've put an insert inside and the insert is Boxwood which obviously takes a good thread. So again, it's overcome a problem for us. Well that was absolutely brilliant Allan, thank you very much. You've shown us the basic principles of thread chasing, but now we've come to our little project, this acorn box. I notice that this is made of two different timbers. Ya, the choice was deliberate. Obviously it looks more like a genuine acorn. I chose Lignum Vitae, which takes an exceptionally good thread as you can see. And I chose Boxwood for the base, which would look like an acorn and also take a good thread, so the two timbers take an exceptionally good thread. Well I'm going to leave that with you and let you get on with it. Thank you Charles. For this little project to be a success, we must follow a certain set of sequences. I'm going to roughly shape the top section of the box itself. That's the first section we're going to do. And I'm going to do that shaping with a 3/8" spindle gouge. And that's as much as I need to do at this point in time. We're now ready to hollow out the inside of the box. For that, I need to take the tool rest across the face of the work. What determines the height of the tool rest is the size of the tool you use. In this particular case I'm using a 3/8 gouge and it must be able to conclude on the center of the work. I'm going to clean up the face first and you'll notice the way I've supported the tool with the little finger and the thumb braised against the blade. My right hand then grasps the lower end of the handle. Make the entry and clean up to the center of the work. One of the dangers at this point is when we hollow out, if the gouge skids sideways, we've wrecked the surface of the work and also the edge of the box. So we can be in absolute control by a simple technique. By cutting from the center back out, cutting on the lower wing of the gouge, we can form a groove into the work. You'll notice what that's given us is a shoulder to work from, so now there's now danger of the gouge skidding away and losing control. It gives me absolute control at the point of contact. As I push in with the gouge, the gouge cant' skid backwards on me and down to the center of the work. Back again. At this stage, if you're not familiar with turning and you're just hollowing out for the first time, when you use the gouge, stop at the center of the work at this point. Now what I tend to do is cut backwards there and then in again so I've got a circular motion going, so the tool cuts both ways. If you're not familiar with this action, only cut down to the center and stop at that point. I continue on and cut backwards and keep working with the gouge now until we've got it hollowed out to that point. And that's how a box is prepared to introduce a second tool which is a scraping tool. And a valuable tip here is when you've freshly ground it, it will leave a burr cast upon the edge of the blade. Remove that by slipstoning the top of the blade. This will avoid the tool snatching in closed grain woods such as this. Now that leaves the question, when to leave the burr on and when to remove it? Very simply the answer is this. We'll remove the burr for any closed grain timbers, but leave the burr on for cross grain timbers such as Oak, Elm, Ash or associated timbers. But by removing the burr here, the tool will not snatch when it goes in to make its entry. I'm actually going to take the tool from the base, sweep around to the side. I'll just clean up any little marks that might remain throughout the surface of the work. But it will also allow me to cut back behind, so we introduce the curve inside the wall now. Down to the base with a scraping on the center line of the work, just go around and cut through there. It only needs a couple of passes to remove any tool marks. And now we're completed inside, ready for our final sanding process We now need to bring our tool rest around to prepare for chasing the thread. Do you remember what we did? We actually brought the rest around at an angle. And now I'm going back to the armrest using the inside tool just to square up this edge and clean it up nice and clean ready to take the thread. Now the problem is that it's left a sharp edge again, so we must remove that. Again I go back to the point tool and just gently round over the edge there. That now is completed and ready to take the thread. But just before we go in with the thread, I'm just going to sand the inside now, because if we sand after we've done the thread, we can damage the thread. So we'll just go through with a fine grade sand paper and I'll just remove any fine, little marks just before we chase the thread properly. And also what I would do at this stage, I would actually finish inside this box now. We're now ready to chase the thread properly and again notice that I've set the tool rest at an angle. The chasing tool goes on the center line of the work there and I'm using the armrest and we swing around and gently does it. The first time we touch the thread, it's so gentle it only just kisses the work. We need to go down to chasing speed from turning speed and I'm dropping down to approximatly 300 RPM. And now the very first time I touch the work with the chasing tool, it's so gently it hardly touches. And now our thread is running properly and I'm bringing the chaser around to square up the threads parallel to the work now. And there's our thread successfully run, nice and clean. And this is an easy thread to run. I didn't need to use the grooving tool because I'm working inside to hollow like a cave. Just a little tip at this point. Sometimes if you're working with a wood that 's crumbling just a little, just keep a toothbrush handy, dip it in wax and wax your threads like that. And as you wax the threads it just lubricates the wood and allows the tool to cut just a little bit smoother right there gently. It is a very clean thread. I'm happy with that. So now I can just use the toothbrush to remove any debris from the thread there. And finally just a quick clean up inside and we'll just have a check now to see what the thread is like. That's an excellent thread, very clean. You can see now while we did the polishing before we did the thread. If you're using a friction polish and you get it in your thread, your thread is going to be ruined. So they're now nice and clean. Nothing in them at all because the toothbrush has removed any problems in there. And we're now ready to shape the box a little bit more around to our final stages. So we need to move the tool rest back to its normal position. And now that we've got the inside completed, the thread chased. We can develop the shape on the outside. It's important at this stage that we don't finish the outside completely. We're just going to get the shape developed, but that's all. Back to turning speed, from the thread chasing speed. You may be wondering at this stage why I haven't completed the outside shape? I'll point that out when we come to the next stage, but this moment in time, the top is finished as far as we're going to go. The inside is complete, the thread is chased. We've now reached as far as we can go with this. The threads completed, the internal side of the box is completed, but the outside shape is not completed yet. An important point we'll pick up on later. We now need to prepare our blank for the base. And as we said earlier, we are using Boxwood for this and we virtually repeat the procedure we used on our test piece earlier on. And first of all we'll cut our spigot. That locates now inside our fitted thread and we'll now leave sufficient wood for our thread. Just removing some waste at this point. And if you remember a priority we discussed earlier was to form a groove again to allow the tool to be removed. We'll do that again with the point tool with the end of the thread. And we'll just clean up our little shoulder. We round it over the leading edge, ready for the thread and now we'll reduce the turning speed of about 300 RPM again and using our outside chaser, move the rest back and I'm going to work in a circular motion as I did before and cut the outside thread there now. Now we can see the thread being formed. Again I'm still not using the lead tooth. The lead tooth is only scratching the surface. Now the thread is running without any problem. And I see that I've left just a little too much wood on here. There isn't a witness mark appeared on the spigot yet and I don't want to go any further with the chaser for fear of stripping the thread.So we'll just have a test fit first. First thread is just picking up, so we can reduce it now to size and complete the thread. Re-introduce the groove at the back so the chaser has time to remove from the surface of the work before it does any damage. Back to chasing speed. 300 RPM and we'll re-cut the thread again. Again nice shavings coming off the chasing tool, which indicates it's sharp. We can see the witness mark appearing now on the surface of the wood there. Good witness mark so hopefully our thread should fit. And there's our thread. An excellent fit. We just now need to remove the spigot, because it's no longer of any practical value to us because it's served its purpose. It's given us our size. Back to turning speed and we'll just remove the spigot. Don't forget at this point to round over that leading edge so we don't have a sharp thread coming out that can crumble. Any now we can just try just a fraction tight. We can ease out now quickly with the chasing tool again. But just take off the crown of the thread so that we don't damage the thread by using this chaser to take it down to size. And now we just quickly just run that thread in finally, ever so gentle. And there's an excellent thread run. Very clean, no damage to the thread whatsoever and we can fit. And there's our lid fitted. But you can see why I didn't complete the shaping when it was on the previous chucking system, because now I can work the whole unit together. Clean up the face. I'll just introduce a little bit of shape to the base and this will help me to define the outside shape of the whole acorn. Just want to reduce that a little. And now you see I can develop the whole shape, so I get the balance to the total job, rather than just shaping one piece at a time and it might not fit with its related partner, where now we can see the shape develop completely from base to top. So now I can see the top needs reducing a little. Just develop the top section here now. Scoop the gouge through. Instead of coming right onto it's back, we take the gouge in at its side at the conclusion of the cut there. Normally we'd have the gouge on its back at that point, but we can't get into that sharp corner. I can develop the shape around on the top of the acorn now and I can redevelop or refine the shape on the base. We can now see how the overall shape has developed as a unit. I can just do any refining process. I've picked up a longer bevel gouge just to give me access through this little shaping here. And the point tool is invaluable just into that corner. That's our acorn, virtually complete on the outside shape. I now need to sand and finish at this stage. Finally just a light wire or steel wool. And now the top section is complete ready for hollowing out and finally finishing the base. We're going to use the gouge in exactly the same way as we did for hollowing out the top of the box. We'll set itjust like we did before and we'll hollow out using the rest as support for the tool. Final cutting now with the gouge. And finally just clean up the inside with a scraping tool. And there's the inside ready. We just need to finish the base of the acorn, so we need to part that off first. We've reached a stage now where it's hollowed out, the top's finished and matches the base, but now we need to complete just this final section around here and the way this is achieved is opening up the base of the waste piece of wood. That's fine. And now we can go down to chasing speed and when we chase an internal thread in here we have an excellent chucking system. We can actually get away with that now. We can now shape that while it's on its own chucking system with its own thread around to completion. And that's the base finished, ready for light sanding. You'll notice that is hasn't been polished at this stage. We're going to polish it separately and independent from the lathe. And as you can see, there's our base finished ready for a little light sanding. The two should fit together now and give us the opportunity for the perfect fit on our thread there. And that concludes our box ready for polishing now. We're going to use an old-fashioned way of polishing by using a polishing mop. So we'll just take the chuck from the lathe, we'll go to a drill chuck and all we have in here is a little piece of wood. And I'm actually going to chase a sixteen thread up that piece of wood and you'll see the purpose for that when it's completed. Thread chasing speed of again approxamatly 300 RPM. Just setting the rest so that it's at the right height for the chaser. A little bit higher because I want to be trailing slightly down. That's it there. And now I just chase a sixteen thread up here now. Having that spine, we've actually got a clean thread run up there and now the purpose of that thread is as you'll see will locate our mop onto the lathe. Just a point at this time, when you choose a mop, choose a loose leaf mop. It's very usefull that we use a loose leaf. If you get the stitch mops, they're a little bit too hard. And we can start our lathe and we can either have it open by being loose leaf and get into the mop like that, or we can take the speed up and have it as hard as we want, so it puts us in control. I'm just going to put a polishing compound on the buffing wheel or mop. It can be anything you want. Carnauba wax, anything at all. And now we'll actually polish the base section first and include the threads within the polishing and that lubricates the threads and makes them extremely clean and now we can polish this section. About this finishing, if the work gets handled and it needs to be re-polished at any time, you just put it back on the mop. And there's our base section done, including the threads. So now you should find that the threads slide up very easy once they're located and they should just spin around and go completely. Now we can polish the top on the base. And again you can see the beauty of this compound. It really does polish the work well. And again we'll slow the speed down so that I can get right into the buffing wheel as we polish and the mop will get around all the little tiny areas that the hard stitch mops won't get into. And there we have one finished acorn box with the threads all polished. There's no squeak in the threads because the threads have been lubricated and polished and now we have a perfectly threaded little box. Now that's a lovely piece of work Allan and you've managed to incorporate all of the chasing techniques into it, but one thing did occur to me. These chasing tools, how do you sharpen them? That's a very good question and unless they're sharpened correctly and very thoroughly, you will not get good clean threads like that. So let's show you how to sharpen them for the future. Before we even switch the grinder on, let's look at safety. You get one pair of eyes, wear a pair of safety goggles. Now we are going to sharpen the outside chaser first and the only part of the chasing tool that we actually touch at all is the top section. We never ever touch the teeth under any circumstances, otherwise we'll them. And by sharpening on the top, we form a slight hollow in here, which if we're working ivory or very closed materials, we can slip stone that and work with that a long time before we re-grind. Switch the grinder on and let it build up to full speed before you put the tool onto the surface and then we search for it just like we search for the bevel of a tool and we just run onto the surface and there what we've got is a lovely clean and fresh grind that's ready to go again. And that will last for many threads before we need to re-grind. In the meantime, we could slip stone that and just continue working much more before we need to go back to the grinder. That's the outside chaser done. Now we'll do the inside chasing tool and again the same rules apply. We must never ever touch the teeth under any circumstances. The only part that we grind is the top surface of the blade here. And again turn on the grinder and let it build up to full speed before you put the chaser on and we'll just put the flat on and run across and what you'll see again, is we've got a clean, fresh grind there without touching or destroying the teeth or their form. And now it's ready to go again and we could slip stone that again to get a very close material to get that perfect thread. So that's thread chasing, now let's look at the top points. First, the chasing tools themselves. On the external tool, I always remove the half tooth (if there is one) on the leading edge to prevent catches. On the internal tool, I alter the profile to make the cutting head narrower. I can then get into more confined spaces. Then a reminder about the grooving tool which has its end ground like a scraper and a riveting edge which cuts the groove in the bottom of the female piece to allow the chasing tool to be removed from the cut safely and at the same time round over the edge of the threaded portion. We also noted the point tool, which was used to round over the leading edge of the female piece to allow the chaser to make a smooth approach. This tool also cuts the V groove in the male piece. This allows the chaser to lift off at the end of each pass. The key point for both chasers is that the lead tooth merely scratches the surface of the work as they move forward and that gently does it. Correct positioning of the tools in relation to the work is essential. The rest set to an angle to the work, while using the armrest and the internal chaser, working at center height. All corners where threads are to be cut, must be rounded. Finally, remember the two methods of striking and chasing male threads. Either by a right to left action, keeping the chaser in one plane, or the rotary action which has better control. Thank you very much Allan for what's been a sparkling lesson. Iv'e learned a great deal and I'm sure that any woodturner who watches this video will want to try their hand at the gentle art of thread chasing. This has been the first in a series of mater classes by Allan Batty. You may want to look out for the next one which will be on the subject of the skew chisel. Goodbye for now.
The first 20 minutes show the tools and technique with a simple working model, then he goes into making a functional display piece.
I'm simply amazed by the hand held tool rest he's using to work the inside of the piece. I've never seen anyone use it. So much more control than just rotating the rest to be perpendicular with the piece.
EDIT: i just made it to the end when he turns the stump of wood left in the chuck into a tHreaded cap to secure the bottom of the box and finish it - mine blown.
Has anyone done this at a higher speed? My lowest speed is 450. I've been looking at doing this for quite a while but haven't pulled the trigger because I'm afraid that just won't be slow enough, every other video I've watched recommends around 250. In this video he says its okay between 200 and 500, but I'm just not sure how comfortable that would be.