Thread: Making planes & making mistakes

Well, I was packing up, prepared for a long holiday from plane-making, but quite a while ago I'd cut out a pair of sides for a small rear-bun smoother which I hadn't proceeded with, for reasons I can't recall. Finding the cut out sides and a blade I'd wrecked when first trying to oil-quench 1080 steel, I had a re-think.

The blade had been tossed aside as wrecked when in my frustration at not being able to get it to harden in oil, I'd dunked it in salt water instead. NOT a good idea, the blade cracked at the junction of the red-hot metal & the cooler metal above it: cracked blade a.jpg

I was about to bin it, when it occurred to me that I could flip it around, cut it off at the split bit, and harden the top part instead (sensibly!). No sooner decided than done, & I had a new, though somewhat attenuated blade. I've had much more success at hardening the 1080 steel since I adopted the routine of dunking the hot metal in oil until it stops bubbling, then cool the last 200 deg. or so in water.

Right, so with the blade sorted, I proceeded with the build. A few planes ago, the idea occurred to me to glue a guide block to the sole to facilitate filing the bevel instread of clamping it on. Ordinary PVA glue left to cure overnight hold remarkable well and it avoids having clamps get in the way & the block is less likely to move during the process. It makes filing a nice clean bevel much easier: 2.jpg

The next job was to bend the sides. This is one step I have not managed to work out any formulas for - I just have to go by experience & guesstimation to figure out how much extra "bend" to put in the form so the sides will come out matching the sole curve when released. This is how much extra curve I put in the form for the sides (which are 170mm long): 3 form shape.jpg

And this is how much spring back occurred: 4 springback.jpg

The sides matched the sole almost perfectly: 5 sides bent.jpg

I think this is as close as I've ever managed to match a side on the first attempt. I wish I could say it was all due to careful calculation but it was just guesswork based on prior experience - if I ever do another curved plane, I can almost guarantee the sides won't come this close first try! Note also, that I haven't cut the "scoop" beside the throat part out. This is a tip I got from a Bill Carter video, to prevent the sides kinking at the narrow part. It does seem to help a lot, I haven't had any trouble since I adopted his suggestion. The dip was cut out after bending, a bit more awkward than cutting a flat piece (note I cut the dovetails before bending, not only would it be more awkward to cut them, it would be more hassle filing the bottoms of the slot dead-even unless I made a curved jig).

I was in two minds about including a blade-block, the thinnish (3mm) blade would have sat on the sole without the block, but only just, so I decided to do it "proper" and add it. The block was duly made & riveted to the sole. I took exceptional care in drilling the holes and am pleased to report the block lined up perfectly (or almost). I've had a couple that managed to squelch out of alignment a bit during the riveting, but this one remained where it was supposed to:
6 blade block.jpg

After that, the body was assembled & peened up, which all went very smoothly: 10 pins done.jpg

..and I was starting to feel a little smug & thinking how I'd got this plane-making business pretty well sorted, so it was inevitable that trouble was just around the corner.....

more to follow shortly

I wanted to use a chunk of Solomon Is. ebony I'd found a few weeks back when looking for something else, for the infill. I had a small, solid chunk for the front bun, and got that fitting very nicely. There was a longer piece than needed for the rear bun so I cut it in half & started on one piece. There were a couple of fine cracks that I thought would not matter, but sure enough, a chunk split out of the rear end just as I was getting it to fit nicely! It was an ugly split that would have been extremely difficult to glue invisibly so I decided it would be wiser to start over on the second piece. That was going along nicely enough:
12 stuffing.jpg

... until another chunk split off along the side. I decided the wood was trying to tell me it didn't want to be stuffing in a plane, so I switched to some Acacia rhodoxylon. That went far better - "western rosewood" is not the easiest wood to work, but it is a quantum leap on SIE! What with the practice & the more pedictable behaviour of the WR, I got a very nice fit.
14 stuffing c.jpg

The only glitch was I over-cut the rebate for the blade block slightly, which left a small gap where it met the blade-block, which I fixed by glueing a strip in the rebate

But now, the most inexplicable blunder of all. I'm usually extremely careful when fitting the lever cap, I try to ensure the toe sits as close as possible across the top of the curved part of the cap-iron, but somehow it ended up a few mm behind the peak of the curve. The relative positions were like this: 15 LC a.jpg

The result was that the plane was near-impossible to set for a fine shaving. The merest, slightest tap would spring the blade assembly forward far too much, and it would go from not-quite cutting to a coarse shaving, time after time . Damn!

No-one would wish to live with a plane like that. I tried "flattening" the top of the curve of the CI by filing it off, but there was only so much I could do without thinning the metal too much. The bit I could take off improved matters a little (supporting my diagnosis), but it was still too touchy for comfort.

The only real cure was to make a new Lever-cap. Here's the roughed out new one behind the original, the pivot points are aligned, and as you can see, the new one extends about 4mm further at the toe: 17 LC c.jpg

That completely solved the setting problem, I could tap the blade for a fine shaving easily: 18 first shavings.jpg

... but the plane didn't feel properly 'solid' the way an infill should, it felt like it wanted to chatter when hitting a knot. That was soon traced to the underside of the toe of the LC not making full contact with the cap-iron, something that has happened more than once before. I could get a feeler gauge under about 1/3rd of the width on the right side. A bit of careful filing & sanding got that sorted and bingo! - a set-able plane that can take even, full-width, 2 thou shavings: 19 LC straightened.jpg

I'm sure there are other blunders waiting to be made if I ever make any more planes, but I've certainly clocked up plenty in my ~12 year career. I'll edit the relevant section of my "manual" to emphasise that the lever-cap needs to end up in the "right" position!

Cheers,

Glad to see you have fallen off the wagon agsin . Lovely!

Originally Posted by Mountain Ash

Glad to see you have fallen off the wagon again...

Not exactly, MA, I plead that I was just finishing off something I started probably a year or more ago, m'lord.

I might remake the thumbscrew for it, I think I still have a piece of brass bar just long enough to hold in the lathe chuck & get at it with the knurling tool. The current thumbscrew is one I made as a demo for my 'manual' to show how you can make a TS without a metal lathe. It's a piece of 8mm SS bolt stuck in a head made from a cutoff piece of 5/8" brass bar, the "knurling" was done by hand with a fine file. It's ok, but a properly knurled head would look better.

I now have nothing but small scraps of brass left, there is nothing big enough to make sides even for a violin plane, just a few bits big enough for wear strips on some marking gauges, maybe, but I don't have any bar for making thumbscrews so I can't even do that unless I find a bit as the clean-up progresses. For the foreseeable future, that's how I want to leave it - absolutely no temptations until the serious shed clean-out & cull is finished....

Cheers,