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  1. #1
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    Default Tips, Techniques and Theory

    Iíve been thinking we should have a separate thread where, in the spirit of this challenge, you can all share problems, solutions & general tips. Rather than clog up the ďjudges cornerĒ thread, I thought it would be better to have a separate thread which Iíve labelled ďTips, Techniques & TheoryĒ.

    Iíll kick it off with some observations on cap irons Ė Matt (Simplicity) saw this in another thread & thought it might be helpful to some of you. I do not profess to be a guru of plane making, there are many, past & present, who have forgotten more about plane-making than Iíll ever know, so take any opinions or advice I offer with a pinch or two of the proverbial.

    What I have found in making planes is that itís often the subtle details that can turn a tolerably functional plane into a superb one. While I try to reason things out from basic principles, I can easily come to wrong conclusions (even for the right reasons!), so donít be afraid to offer counter-opinions. I think we are all here to learn, and anyone who learns something useful is a winner.

    OK, enough guff, letís get the ball rolling with a short discussion on Ďtheory & practiceí of cap-irons.

    I think enough has been written & said about cap-irons for most of us to accept that they are not just to stiffen thin blades & provide something for screw adjusters to hold onto, but will help to control ďtear outĒ when properly fettled &set. They are, therefore a desirable feature in any plane designed for fine work, when it is practical to include one.
    If you do wish to include a chip breaker/cap iron in your masterpiece, there are plenty of factory made blade/cap-iron combinations available. However in the DIY spirit of the challenge, you may wish to roll your own & itís not that difficult to do. The only extra tool that you might not have on hand is a tap for a retaining screw (unless you plan to use a ďlooseĒ cap-iron as on Japanese planes).

    I like to use stainless steel for cap-irons because it polishes up nicely & doesnít corrode, but mild steel will work (itís what the vast majority are made from) and ideal thickness (imo) is 2- 2.5mm. You may find 3.2mm is easier to obtain, itís a little harder to bend, but will do the job. Anything thinner than 2mm is going to be less stiff, and gives a very shallow thread for the retaining screw. (Iíve measured quite a few cap irons off Bailey type planes and they are usually around 1.75mm thick, which is probably the minimum practical thickness.)

    Cutting & shaping is straightforward Ė use a hacksaw or cuttoff disc & tidy to the lines with files.

    Now for the bend.
    You can do this a couple of ways. The easiest is to clamp about 5-6mm of the end in a vise & push it over. Use a solid lump of wood to maintain pressure across the metal & keep the bend even. This tends to produce a rather sharp bend, which you can fair into a curve by filing.

    To produce curved bends a bit more controllably, Iíve made a crude jig with some scrap steel & 19mm bar. I welded the two pieces of bar to the steel, but they could be bolted if you donít have access to a welder. A third bar acts as the bending dolly & by choosing different diameter bars I can vary the sharpness of the curve : 3.jpg

    (continued...)
    IW

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  3. #2
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    Default Cap-irons continued

    Although crude & simple, my jig does the job, and produces a cap-iron that does an adequate job: 1a.jpg

    Now, for a blade assembly retained by a wedge, a single-bend cap-iron is perfectly satisfactory because it presents a straight, flat surface for the wedge to bear on. This style is what youíll see on old woodies, but they also used very thick blades, so the thick, single-bend cap-irons donít cause them to bow when the retaining screw is tightened. For a thin blade, a heavy, single-bend CI can cause a very pronounced bow in the blade when the screw is tightened up which in some cases, may cause you problems getting your blade to bed well: 1b.jpg

    You can use this style of cap-iron with a lever-cap, but itís often not ideal because a single-bend cap-iron/blade assembly is like a wedge, so when you tap your blade to increase the cut it loosens. This is less noticeable with wooden wedges, the compressible nature of wood usually maintains pressure to hold thins firmly for the short amount of blade movement, so your blade & cap-iron are unlikely to come shooting out of the mouth. Not so with a metal lever-cap, which is bearing on the blade assembly at just two points which means even a gentle tap often advances the blade far more than you intended. Itís a minor problem and I used single-bend cap irons for a long while, but they can be particularly frustrating when you are trying to set for that perfect 1 thou cut.

    Enter the ďdouble bendĒ cap iron. By bending the end of the cap-iron up and over in an arc, you can have your cake & eat it too. Now, the bulk of the cap-iron lies flat on the blade, (pic 2) and causes no flexing when they are screwed tightly together. The curve in the CI acts as a spring, and if you get the conformation right, the lever-cap compresses the curve just enough that moving the blade back & forth a mm or so doesnít materially alter the pressure of the cap-iron against the blade (this is one reason why a Bailey type plane is easily adjusted without backing off the lever cap): 2.jpg

    OK, but of course itís harder to make an accurate double bend with primitive gear, & to ensure that the top of the curved section will be precisely under the edge of the lever cap. Thatís really only a problem if you are making a new cap-iron for an existing plane; if you are building the plane from scratch you simply fit your lever cap so it bears down in exactly the right place.

    It takes a bit of fiddling to set up the blank for each bend, particularly the second one (& moreso for a skewed iron as this one is being prepared for), but with half a roll of duct-tape and a few choice expletives, it hangs together while I get it in the vise for a good squeeze: 4.jpg

    I first press a curve at the end, flip it over, and put the second bend in. Watch each bend and squeeze until you think you have the right amount of curve. Release the pressure carefully and watch how much it springs back Ė if you think itís not curved enough, just give it a bit more of a squeeze Ďtil itís done to your satisfaction: 5.jpg

    With careful setting up, you can get a pretty accurate bend but even a slightly wonky bend can be straightened up with files and sandpaper (use a hard, flat block to back the paper). Refining the mating edge is the most critical part. It needs to be filed down until the cap-iron can be pushed down flat on the blade, applying plenty of pressure along the mating edge, without causing any appreciable flexing of the blade. Trial & error will eventually gey you there, & once youíve got a nice fit, you can pretty up the rest of it. 6.jpg

    I donít usually drill & tap for the retaining screw until the bending & shaping is finished, so that I can place it accurately at the end of the blade slot & ensure a maximum amount of usable blade. 7.jpg

    Bending doesnít always go exactly to plan, and I may end up needing to chop more off the edge when tidying up the bend than I expect to. Or worse, Iíve had the bend go completely off the rails (like bending the wrong way for a skewed iron!), so I usually donít cut the blank to length & shape the upper end until the bend has been formed in case I have to start over.

    Polish the front of the curve up as clean & smooth as you can get it; this helps even the fluffiest 1 thou shavings shoot up the escapement instead of compacting themselves down in the throat: 8.jpg

    It has taken me quite a few years & quite a few planes to figure out some of these finer points of cap-irons, but itís getting such small details right that turn a good plane into an absolute crackerÖ

    Cheers,
    IW

  4. #3
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    Default

    Ian, I think this thread is a great idea.

    And I would like to share a variation to your cap iron bending jig. A while back I got a Stanley #2, but the cap iron wasn't right. I ended up making a new one out of an old #4 cap iron. That involved flattening the #4 iron and cutting to width. After that I had to roll a new bend at a different position.
    I remembered Ian's jig but did not have any steel and welding abilities to make one. So I made one of hard wood by simply cutting a wide groove into it. And then using it the same way as Ian with a thick steel rod I had in the vice.



    After that I just had to cut it length and fitting to the blade.

    Now the plane works a charm.

    Sent from my SM-G950F using Tapatalk

  5. #4
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    Default

    Excellent, Ck, a good solution! I suppose you could rout a rounded groove in your block with a cove bit to match the required bend. But your simple jig worked, so no need to fix what ain't broke.

    That is just the sort of thing I had in mind for this thread - how to get something done with what you have to hand...

    Cheers,
    IW

  6. #5
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    Default

    My lever cap design thoughts !

    Following on from Ianís thread on Chip breakers and Lever caps Cap Irons.
    My at present idea is what I think is called a hung Cap(I may have just made that up).
    Whatís everyone opinions on this type of Lever Cap.
    Pros and Cons.
    I personally like the idea because it removes the fastener(Bolts)from the side of the plane.
    Yes thereís more work involved, but itís a Zen thing.
    My plan would be to peen the ends of the cross bar(4 mm diameter),hopefully making them almost invisible!!.
    I first saw this idea on the internet and then duly forgot about it.

    Cheers Matt.

  7. #6
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    Default

    Well Matt, it’s definitely a case of great minds think alike at work here. This is the same style lever cap I am planning to use, but I was gonna keep it under wraps till the end.
    The cats out of the bag now .
    I have seen another variation where the slot for the pin is on the top side of the cap, but I like it on the bottom side, like you have depicted in your drawing because it looks like a traditional lever cap from the top.

    I also have seen on some of Karl Holtey’s planes where he mills slots into the sides of the lever cap, and has short stubs riveted into the sides of the plane for the lever cap to slide onto. I like this design also, but I don’t have the gear to do it properly, I think a milling machine would be needed.

    The only thing I would be concerned with on your design is the thickness of material left after cutting the slot, it might allow your lever cap to flex. I am using 3/4 inch brass plate for mine , so should have enough thickness to retain strength.
    ​Brad.

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    Default

    I like it; but with two notes:

    Firstly I think youíre putting the pivot too high up; all the lever caps I can think of have the pivot below the half-way mark.

    Secondly; you can reduce the amount of filing needed by cutting out the middle section. What I mean is that you only need the ďhooksĒ at the extreme ends of the caps; and probably only about 1/4Ē of ďmeatĒ at that. The bit in the middle can be carved out by whatever means you have available prior to filing the internal shape.
    Nothing succeeds like a budgie without a beak.

  9. #8
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    Quote Originally Posted by Ironwood View Post
    Well Matt, itís definitely a case of great minds think alike at work here. This is the same style lever cap I am planning to use, but I was gonna keep it under wraps till the end.
    The cats out of the bag now .
    I have seen another variation where the slot for the pin is on the top side of the cap, but I like it on the bottom side, like you have depicted in your drawing because it looks like a traditional lever cap from the top.

    I also have seen on some of Karl Holteyís planes where he mills slots into the sides of the lever cap, and has short stubs riveted into the sides of the plane for the lever cap to slide onto. I like this design also, but I donít have the gear to do it properly, I think a milling machine would be needed.

    The only thing I would be concerned with on your design is the thickness of material left after cutting the slot, it might allow your lever cap to flex. I am using 3/4 inch brass plate for mine , so should have enough thickness to retain strength.


    Brad,
    This whole thing is about caring and sharing, can you not feel the LOVE.

    Great mind think alike , I think Iíve seen the other versions as well,Brad, they look great too.

    I also lack a Milling machine, tho itís high up on the toy list.

    My thinking is the cross pin is 4 mm,that leaves 3 mm either side on the Lever Cap.
    My blade iron will be 6 mm.
    You can only tighten the bolt with finger pressure.
    I wonít be using my 1/2 inch breaker bar to tighten it lol.
    So ďhopefullyĒ thatís enough, but Iím open to being told otherwise.

    Cheers Matt.

  10. #9
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    Quote Originally Posted by Simplicity View Post
    Brad,
    This whole thing is about caring and sharing, can you not feel the LOVE.

    Great mind think alike , I think Iíve seen the other versions as well,Brad, they look great too.

    I also lack a Milling machine, tho itís high up on the toy list.

    My thinking is the cross pin is 4 mm,that leaves 3 mm either side on the Lever Cap.
    My blade iron will be 6 mm.
    You can only tighten the bolt with finger pressure.
    I wonít be using my 1/2 inch breaker bar to tighten it lol.
    So ďhopefullyĒ thatís enough, but Iím open to being told otherwise.

    Cheers Matt.
    I am using a 6mm stainless cross pin, probably why I was concerned with the the thickness of your plate, plus I also tend to overengineer everything I make .
    ​Brad.

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    Quote Originally Posted by Ironwood View Post
    I am using a 6mm stainless cross pin, probably why I was concerned with the the thickness of your plate, plus I also tend to overengineer everything I make .
    I to am constantly being told I over think over engineer everything, lol.

    My cross pin will be Brass, so you may win out on being stiffer there using Stainless Steel.

    Cheers Matt.

  12. #11
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    Quote Originally Posted by Chief Tiff View Post
    I like it; but with two notes:

    Firstly I think youíre putting the pivot too high up; all the lever caps I can think of have the pivot below the half-way mark.

    Secondly; you can reduce the amount of filing needed by cutting out the middle section. What I mean is that you only need the ďhooksĒ at the extreme ends of the caps; and probably only about 1/4Ē of ďmeatĒ at that. The bit in the middle can be carved out by whatever means you have available prior to filing the internal shape.
    Chief, you are on the money with the position of the pin, the lower it is, the more mechanical advantage you will get when tightening the screw.

    I like your idea of just leaving the hooks at the sides, I think I will use that on mine if you donít mind.
    ​Brad.

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    Quote Originally Posted by Chief Tiff View Post
    I like it; but with two notes:

    Firstly I think youíre putting the pivot too high up; all the lever caps I can think of have the pivot below the half-way mark.

    Secondly; you can reduce the amount of filing needed by cutting out the middle section. What I mean is that you only need the ďhooksĒ at the extreme ends of the caps; and probably only about 1/4Ē of ďmeatĒ at that. The bit in the middle can be carved out by whatever means you have available prior to filing the internal shape.
    Chief,
    That was a five second sketch , but I agree Iíve got the pivot point too high.
    Also I agree it wonít need much meat to hook on and stay in place.

    An also I like your point about hogging out some of the Fat from it.
    Just last night I put some stuff together like so(components)
    Itís getting heavy already,and thatís not the end of it.


    Cheers Matt.
    I think there might be some more fancy filling coming, in the name of weight reduction.

  14. #13
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    Quote Originally Posted by Simplicity View Post
    My lever cap design thoughts !

    Following on from Ianís thread on Chip breakers and Lever caps Cap Irons.
    My at present idea is what I think is called a hung Cap(I may have just made that up).
    Whatís everyone opinions on this type of Lever Cap.
    Pros and Cons.
    I personally like the idea because it removes the fastener(Bolts)from the side of the plane.
    Yes thereís more work involved, but itís a Zen thing.
    My plan would be to peen the ends of the cross bar(4 mm diameter),hopefully making them almost invisible!!.
    I first saw this idea on the internet and then duly forgot about it.

    Cheers Matt.
    I like that design and have seen it before as well. If you have a drill press and can drill through from the side and then use a hack saw to cut to the hole, then the filing can be reduced.

    But anyway I have a more general question to lever caps. There seems to be some anxiety around fitting lever caps and I do not understand why. Maybe because I have not done that yet myself. So maybe someone can elaborate a bit more on the pit falls when it comes to lever caps?

    Sent from my SM-G950F using Tapatalk

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    Was just thinking, if you are using thinnish brass plate for your LC, you could probably braze a couple of tabs on the back to cut the hooks into.
    ​Brad.

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    Quote Originally Posted by Cklett View Post
    But anyway I have a more general question to lever caps. There seems to be some anxiety around fitting lever caps and I do not understand why. Maybe because I have not done that yet myself. So maybe someone can elaborate a bit more on the pit falls when it comes to lever caps?

    Sent from my SM-G950F using Tapatalk
    I think where the concern is, if you donít get pivot holes lined up perfectly parallel with the face of the blade, you will have trouble getting even pressure across the blade applied by the LC .
    I am a little concerned with this because I am going to drill my holes in the sides before I bend the sides and pein them to the bottom plate. I will be meticulous with my marking out and cutting, hopefully I can avoid any pitfalls. I will also allow a bit of extra meat on the end of the LC where it will contact the blade, so I can do a bit of fettling once itís all together.
    ​Brad.

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