Preparing the chip breaker for use

no bench plane is going to work well unless the chipbreaker front edge is properly prepared and it's an unfortunate fact that they don't come fully finished from the manufacturer now I find this a little bizarre and I rather wished manufacturers would tell you that the front edge of chipbreaker is not actually quite ready to work so let's have a look at this one this is a new one and we'll have a little look and see what we've got now this style was introduced by Lee Nielsen a number of years ago they call it the new improved chip breaker and I like the design a lot under the front edge here we have a lip which has clearly been machined the front edge of this lip must make perfect contact the prepared back of our blade and that was one of the main reasons for us to get the back flat in its width if we get this flat in its width and if we can arrange to tilt this surface by about one and a half degrees we'll have a perfect job now you may wonder why I'm talking about tilting the surface another way of putting it is we're building in a little bit of a clearance angle and it's an engineering trick to ensure that the front edge contacts if we try to make the whole thing flat it would be much more difficult to arrange why does the front edge need to fit it needs to fit so that shavings which climb up the blade can't get stuck underneath the edge a chip breaker not fitting its blade is one of the principal causes of choking which is where the shavings stake and then they build up and then after a short while the plane stops working all together and people are often a bit mystified about this and they find that moving the chip break our way back out of the way she was the problem but the chip breaker actually has a function in planing and usually it wants to be pretty close the old texts tell us to set it about a sixteenth of an inch away from the edge for heavy work and as close to the edge as possible for the fine finishing of difficult Timbers now many text books will show somebody working the underside of a chip breaker on a stone I've chosen to use a diamond stone just for convenience it means I can work away if necessary and not have to constantly think about flattening it now this stone is about 9 millimeters thick and this little wooden prop I've got here is about six millimeters thick it says 6.2 but we I think we can ignore the point - some years ago not very many years ago I had a very nice pilot on a short course and he taught me the one in sixty rule and I believe it's something that they fall back on if the landings aren't going too well if you think of a triangle 60 units one way and one unit to the side is almost exactly one degree now I'm exploiting that rule because it so happens that the chip breaker here is about 120 millimeters long I'm cheating a little bit it's actually a little bit longer so if I have a wooden prop it's approximately three millimeters lower than the stone I'm putting a clearance angle of 1.5 degrees on this front lip and that will be very convenient because when we did the work to make with the ruler trick we are in fact imposing a very small back bevel on the blade and I've done the trigonometry and work to have the sums and the little polished surface is at an angle two thirds of one degree so by ensuring that the front lip of the chipbreaker is one and a half degrees clearance angle I know that it's the front edge that will touch the blade now it's a it's not very good practice to do sharpening on your bench so I'm going to move things over to the charming match [Music] I'm going to use a red DMT stone this is what they call fine but I think this is in very good condition visually and I'm not expecting to have to do a lot of work I'm not going to put my prop sideways and that would particularly apply to old planes because quite often there is a twist the twist of course is sucked out when it's screwed onto the blade but it might upset us here so I'm using the three-legged stool principle now this interesting mixture is just an anti rust cutting fluid it's water with a net additives and I don't know what the additives are but it doesn't rush things I'm going to put pressure only in the center my objective for this job will be to get a prepared surface perhaps half a mil wide between half a mil and a millimeter be quite enough I don't have to clean the whole of the lid this chipbreaker is in excellent condition and I've nearly achieved my band of metal which is at one and a half degrees to the surface I'm nearly done it already I'll just do a few more rubs some old planes this can be quite a job but the machining here is excellent apart from polishing it up a little bit that underneath surface is finished I now transfer my attention to this top surface Lee Nielsen grind their chip breakers of 25 degrees but all the planes I've worked with and Stan Lee were clearly aiming at 45 degrees for the last hundred years or so a 45-degree edge on the front of the chip breaker is one that is not likely to cause choking when the shaving comes up and goes up vertically it won't file the front edge of the throat which is vertical so I like to put a little 45 degree bevel on here huh I'll polish it quite a bit because all future shavings are going to come sliding up over this surface now there is in fact a small square edge on the front of this if I set up at 45 degrees in a honing guide and I take some strokes the presence of a wire edge on this surface will tell me that the bluntness of the square edge has gone it's just like in ordinary sharpening so here we go I've set this bevel up it's a 45 degrees a little trial and error I should arrive at 45 degrees that looks pretty much spot-on to me a little bit more cutting fluid and I will black this top surface because I want to try and make it reasonably neat and even but my main signal is going to be the presence of a wire edge on this top surface and I've got a small square edge to get rid of now we can see the surface that I'm beginning to produce no sign of a wire edge yet I think I'm going to be adventurous and try forward and back strokes very unusual for me I get my beginners doing cool strokes only because they're less likely to dig into the stone and I just sort of got stuck with out have it I'm looking to see if this is even really just for aesthetic reasons sometimes we press much harder with one side than the other and that could cause a crooked result here's a wire edge here's a wire edge here's a wire edge continuous wire edge all the way across that tells me we're getting to the sharp stage now the beauty of these little techniques of mine are as I can now go to a finer stone without taking this out of the honing guide I can put it on the prop and just do a very few strokes that was five tiny little two and froze having done that the wire edge would have been pushed back to the beveled side where I can feel it so again I'm going to do five very gentle strokes possibly even three the wire edge flips back to the other side chip breakers are usually made of soft metal and what we've got here is something that I call a persistent wire edge it doesn't drop off in the pleasing manner that it does with a hardened steel so what we have to do is we have to work from side to side with less and less strokes on finer and finer material until we persuade it to fall off now it's still there a little bit but it feels quite weak to me so I'm going to switch to doing an old technology which is to strop this on my hand this is what we always used to do when we sharpen Don oil stones we're just bending the wire edge backwards and forwards till hopefully eventually it falls off and it has done so just one final step I think I've talked about shavings going up over this surface the more it's polished the better and this little technique as I'm about to show you it's very very good for routine maintenance or sometimes you'll work timbers with a very high tannin content and what you'll find is you get a blue-black stain building up on the chip raker and four knots while wool and a little metal polish this one's very good I'm sure there are lots of good metal polishes it's a very good way of maintaining and polishing things I've pressed it onto the MDF and lifted it slightly to protect that sharp edge I don't really want to blunt it and I'm gonna rub like hell I'm going to do a little bit to the underside as well because it's a 45 degree edge I'm going to lift this up to about 50 final step no 2 2 or steps this may be extremely sharp I'm going to allow myself one little rub in each direction just to remove the extreme sharpness and then I'm going to polish with paper do be careful not to cut yourself this thing is sharp now and this is why you always see craftsmen being so careful when they remove a chipbreaker and they pull it back from the edge they slide it across its partly to avoid damaging the edge but it's also to avoid damaging this precious edge on our chip breaker

Channel: David Charlesworth

Views: 10,294

Rating: 4.9889197 out of 5

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Id: 26MIz2ywD04

Length: 16min 28sec (988 seconds)

Published: Wed Apr 15 2020