Hss Boring bars - Hss Bohrstangen

hey welcome back to the shop I want to make a set of boring bars for very long time these are twelve millimeter boring bars that fit my trip and tool holders should these are 10 millimeter boring bars also for the tree pan holder with a reducing sleeve and these are eight millimeter boring bars that fit my will help the boring head each size has one with the cutting bit at 90 degrees for through holes and one with cutting bit at 45 degrees to machine up to a shoulder all our machine from drill rod and take a three millimeter high speed steel or carbide cutting bit and the bigger ones are the 8 the 12 and 10 millimeter boring bars are slit in front here and have a clamping screw here to clamp the cutting bit and the small 8 millimeter borne boards are drilled through and the cutting bit is clamped with a set screw from the back because I didn't have room for a clamping screw in frontier if you want to see how these are made hang around I will show you okay first step is to face the parts to length and put a nice chamfer on them so they are nice to handle okay now as we have the raw stock faced to length we're going to drill the drill and ring the holes for the cutting bits I want to use three millimeter high speed steel and carbide cutting bits so we're going to drill and remit to three millimeters I dragged out my call it block shot made of course and already clamped up one of the twelve millimeter boring bar blanks first we will do all the drilling for the 90 degree boring bars then we will do all the 45 degree boring bars and then we will do the clamping the clamping threat on the two bigger sizes and obviously we will cut the slit the clamping slit so let's go to the mill and do the setup okay when I do setup select this I like the I like the workpiece against the stop not the collet block because that way the actual stick out out of the colored block is not critical if I have it overhang that much it's the same as if I had only ten millimeters or something like that off stick out and that makes for faster working so I clamped the part in the color block I tighten it down then I just slip it up against the stop and slap it now the nice thing is I only have to loosen the nut pull out the workpiece and push in the next workpiece up against the stop and I don't have to disturb my setting on on the colored block itself and rear edge finding the center and the end of the piece okay we're going to drill and ream a three millimeter hole I moved in two millimeters - the radius of the hole we will have a 0.5 millimeter of wall thickness left to the end of the border there we go grilled 2.8 millimeters and now we follow it with a three millimeter Rema Rema of course low speed and a good amount of oil okay that's my setup for the 45-degree drills flooring bar okay that's my setup for the 45-degree boring bars just clamping down the colored block and while the y-direction still still well it the x-direction of course is yes somewhere but when I turned the parts to length I machined a pretty big chamfer on the end on the business end of the barn bar and that's what we're going to use to to get our new X x coordinate and we will just line it up by eye I have my starter drill in here and we can just move it until the tip of the drill is in the center of the chamfer okay that looks about right let's start with the spotting grill at a proper speed there we go okay I'd drilled and deep bird all of them and I have a sermon on high speed steel blank here and you can see these are the 90-degree ones with the tool where it goes to the edge but you can still not machine a flat-bottomed hole with these or machine up against the shoulder because the the boring bar itself would hit bottom for the cutting edge for that you need this style where the cutting bit is at 45 degree and it's sticking out to the side and to the front of the boring bar and with this one you can come in bore up to a shoulder and face in or face out whatever you want next we will finish the small of boring bars by by drilling them from the rear and tapping the rear end and then we will make a push rod that goes in and holds the high speed steel blank in there so let's go to Italy okay next step is to grill these boring bars from the rear all the way up to the cross hole at least the small ones and that's to clamp the cutting bit with a long push rod and set screw in back so let's do this and as you can see this approaches about 50 millimeters long and we need to drill in with a three millimeter drill and that's quite deep that's yeah a 15 times diameter deep end when you're drilling that deep with such small drills take your time pull the tool out quite often and use plenty of oil otherwise you will cease the drill bit especially when you drill deeper than your flutes and you will see that I start with the drill bit clamped up short and then I will pull it out further and further out of the drill chuck and in fact we start with a two point eight millimeter drill bit and then I will run a three millimeter drill bit through to clean it up I'm not going to ream it because I want the push pin in there to move freely and my reamers produce a very close sliding fit so I'm good I wanted to want it to slide for you okay we need to pull up drill bit more now we're camping only on the last 10 millimetres after drill bit of the shank and because of that you can't start with dribble to extended that white out because as you see it gets quite flexible okay we're through now we change to a chrome 3 millimeter drill and clean up the hole now we open up the end to three point three millimeters and tap it formul into the threat there we go okay let's take a look I drilled both of the boring bars the small boring bars completely through and I tapped the end for an m4 thread then I cut off some drill rod three millimeter drill rod which slides freely into the end of the boring bar like this and the same for this one with only one difference I filed the end to two angle of 45 degree because the hole in this one is of course for the first degrees now we will assemble them first we take the push pin we drop it in the end and we take one of the four millimeter set screws we're screwed and we take a high-speed steel bit this is three millimeter steel cobalt 12 that's 12 percent cobalt one of the highest grades high speed steel you can get obviously these are too long I have to cut them down just with a small cutoff wheel then it goes in here and when we tighten down the set screw back here we push the pin inside the boring bar to the front and obviously lock lock the cutting bit in position and when we lose Indy setscrew like this we can of course pull it out and get it back in back out change our bits get it back in we grind it whatever we want put it back tighten the setscrew doesn't need much not much torque I'm just like this and this should be more than strong enough to take that small cutting forces and what when you wonder what I need these eight millimeter boring bars pretty short ones yeah now it's obvious huh for my bowl of the boring head which takes ignominy tooling and of course a boring head you want a short as possible stick out and that's 35 millimeters working depth I think yeah about 35 millimeters and that's for a lot of jobs good enough I have some borne bars that are long or with eight millimeter shank also some carbide insert boring bars but the inserted boring bars have the problem that they introduce a lot of cutting pressure and with boring hand that always a bit of problem and the 45-degree one works just the same we take the pushpin get in front take our cutting bit set screw and back and cut it down and the 45-degree end on the pushpin aligns itself of the cutting bit and should lock it yes locks it in position with just a little bit of torque and releases it also so you set up your cutting bit like this so it it pre cutes slightly above the edge of your boring boring they're good to go and you tighten the setscrew back here when you want to change the bit you loosen it and you pull it out so these are the real locking boring bars but obviously we can't do this to the long boring bars for lathe because that looks because that will call for some serious deep hole drilling and that's 110 millimeters deep and drilling hundred and ten millimeters deep with a three or four millimeter drill bit that's really no fun without special setups so we will set them up on the milling machine again we will drill a drill tap a hole 90 degrees offset to the to the first hole and then we will slit them so we can clamped a complete front and down with a single set to a single screw I didn't want to do this with the smaller boring bars because there is not much material for a fork screwing but we'll see 1012 minutes this should work this should work out fine okay I set the code block up high above device and now we will drill and tap the clamping hole thread thing and then we will slip it 90 degrees and we drilled the relief for the slot and then we will slip it back and cut the relief slot with a slitting saw so let's get started first of all we need to to align it so that the the crust hole for cutting with this kind of square and for that we can of course use a cutting bit and I will look down from this side and just eyeball it level and I will almost tighten down the the collet nut just just eyeballing a buff to cutting bit and lining it up boo Joey with the with the color-block doesn't need to be 100% on come on a boring with 6-minute and mill and if I didn't mess up anything we shouldn't break with the cardboard into the cross hole but we will see carbide end mill 500 rpm and some cutting off yeah maybe like this still doesn't feel very good let's slow it down a bit more okay yeah I should have run it from the get-go very very very slow yes okay I just cross-drilled the boring bar that's the side with the drilled and tapped hole counterbore for a socket head screw and that's the relief for the saw cut we're going to put in there so let's flipped around once once once more against the stop and now we're going to use our more SEPA - saw Harbor that we made in a previous video with one millimeter fine pitch saw blade slitting saw okay I send out the slitting saw we're running it at 95 RPM I will take a shallow pass across and we will come back and feed it oops okay you saw that was very uneventful and we did a nice straight cut as looks so piece of cake and I could feel it pretty fast and once you get some water on of a appropriate feed D the noise of the saw blade also goes to a more subtle noise and net not that Kirk Kirk Kirk then it's more like hum be on this channel special sound effect okay um that's the first of the Bourne bores finished and let me take out the screw you see that the slip goes all the way through the 45-degree hole into the relief hole and the cross the cross drilled the hole for the screw with the thread passes barely against the hole for the cutting bit now when we put in the screw we obviously can tighten down this and when we now insert a three millimeter high speed steel blank like this and tighten unscrew squared briefly doesn't really need much it's it's safe in position no no way to move no way to move this and we have overhang to the side and to the front so we can and the drill when we grind an appropriate cutting insert or cutting bit we can use this for to work up against the shoulder like this design and I didn't come up with this design I saw this for this this basic design with the screw in front here in a German forum published by Dominique so thank you for showing us that it's pretty good design and I liked it so I copied it yeah and this design with D to push artists of course courtesy of George H Thomas so I will finish the remaining boring bars off camera because it's it's always the same process drilling drilling and running the sledding saw into it and we will be back with grinding the insert the cutting bits okay now it's the boring bars or finish we are grinding the cutting bits that go in there and I already have peace for I already ground cutting bits for these four boring bars and I will show you how to grind them on on the bigger boring bars as an example the raw material is high speed steel cobalt 12 that's the good stuff twelve percent cobalt these are high temperature and very hard even if they get blue on grinder doesn't matter still hard as you can't anneal this with normal measures same for her cobalt 8 and cobalt 5 so always make sure you get high-speed steel with cobalt without waste of time in my mind yeah and the dust from the high speed steel grinding is toxic and will you and cobalt this bad for health and so on its own and of safety briefing these are some lip cutter planks that's the reason why they are already split to half at the end but doesn't matter for us we just want round high speed steel blank but I'll start with the boring bar with the 45-degree bore with this one and to make the grinding easier we can use the boring bar as a holder so we take one of the high speed steel pieces clamp it in the boring bar and so we have something to hold on when you're working at the grinder well let's go to Grandda okay prep the grinder this is an old bench grinder with 150 millimeter wheels and first step is to to split the end of the high speed steel to half thickness they're just going to hold it like this against the grinding wheel and I will tilt it slightly in that direction so we get a bit of rake and the splitter to have it's not super critical okay now we grind the front rake we want clearance to the center so we tilted that way and clearance to the bottoms of we tilted back okay and now for the side clearance we want clearance in that direction so we tilt it that direction and back cleanse so we turn it slightly that direction and that's it that's all the grinding that has to be done on the bench grinder let's go back and hone the address by hand okay I hope you are able to see this this is the cutting edge we just produced and we have clearance to the center like this and back clearance like this and some back rake here and here so only the cutting edge is protruding everything else is ground back and now we're going to hone the edge slightly I like these small triangular stones for this this is a aluminum oxide stone and I just work site I hold both parts at freehand not resting anything on the bench only resting my hands on the bench and I I tilt the stone on the surface and you feel when it sits flat on it and then you just worked the surface just like this doesn't need much when like when the cutting edge gets shiny you're good to go don't doesn't need anymore no need to get the whole surface cleaned same down here looks a bit awkward because I'm working around tripod and same here cutting edge got got shiny and now for the top surface we can do the same we just hit it lightly with the stove now we can put a small radii on the edge I like to hold it that way and you grind away from the cutting edge so take so you don't pull out the bird onto the cutting edge you want to pull the burr back then you chip do this and this is really hard to see on camera but there is a teeny tiny small radius on the edge now you only want the radius on D on the cutting corner not on the cutting edges because when you put a radius on the cutting edges you dolt - it's not going to cut or at least not with low pressure and now we need to to cut it to length for that we could use it a toy like this with the small cut off wheels but as these are rubbish they cut so slow and so earth better way faster first we have to determine the final length of the cutting bit so we pull it back clamp it and we take our felt pen and make a mark here pull the tool out we got a big mess and a mark how long the cutting bit needs to be so let's go to the bench grinder and cut this out okay to cut them off we just grind a nick all around on the edge of the grinding wheel yes you should not grind on the edge of the cutting wheel but I do it anyway then you just go to your bench wise clamp it up and snap the overhang off it's bit faster than using the tiny cutoff disk then you can clean up the end on the bench grinder again okay that's old boring bars I hope that was somewhat useful oh by the way when you asked about the angles on the boring on the cutting bits yeah doesn't matter five degrees seven degrees 10 degrees 15 degree it works so it's only a matter of to life and surface finish I generally shoot for 10 degrees in all direction so 10 degrees clearance angle 10 degree top rake angle and 10 10 degrees relief relief can be a bit less or back relief yeah you know a tool chest should cut that not rough so try it out I'm not a big fan of advocating angles on cutting tools because at the end of the day it doesn't matter so thank you for watching see you next time

Channel: Stefan Gotteswinter

Views: 95,283

Rating: 4.9545698 out of 5

Keywords: boring bar, boring, slitting saw, sägeblatt, ausdrehstahl, bohrstange, innendrehmeissel

Id: O9d_I0A4kzg

Length: 36min 43sec (2203 seconds)

Published: Mon Feb 01 2016