Thread: Shank geometry and wedge design...

Taking another step in the restoration learning curve.

I understand the shank tapers in at least one, often two directions and is it this taper that causes, and requires, the scales to flex and bow. I am looking for explanation on how this relates to the size, shape and taper of the wedge.

Thanks in advance!

Don't quote me, but I am sure I read and have applied this theory,
that the wedge should about half the thickness of the spine & tapper so it is about a 1/8" wider then the tang before fitting pivot pin
Someone else be able to confirm this

Okay, that's a start. Thank you.

But if I am correct on the tang tapering, which I recall Glen saying more than once, than which tang measurement? The width at it's widest?

And here's the next question... Does the wedge taper in only one direction? A true wedge shape? I have a W&B where the wedge appears to taper from the inboard blade side to it's outboard edge AND from top to bottom with the bottom being the narrower part. So the thickest part is the top near the blade and the narrowest is out board at the bottom. I haven't unpinned it, but it appears as though the scales would spread both outward and open at the top, like a flower petal. It could be an optical illusion stemming from the shape of the scales at the pinned end.

You are learning this all on your own one hint Calipers are no longer expensive and can really help in finding answers

To confirm what you have written, Yes the tang tapers from front to rear and from top to bottom
Yes many vintage wedges do also taper top to bottom, I have not seen enough of a system here to call it intentional
I do however use it in my builds, and allow the wedge to taper from bottom to top the top being ever so slightly thinner.

To start your wedge if you start at about 1/2 the thickness of the tang at the pivot you should end up pretty good.. I have over the years made my wedges thinner and thinner more like the Vintage ones but so long as the angle matches you should be fine... Most every Vintage wedge measures between .045 -.065 at the end of the scales so I use that as a target again Calipers are no longer cost prohibitive...


The best thing you can do is when the old ones are apart use the calipers to measure what those old farts did, and learn from them

Glen pretty much said it. I've seen a lot of old Sheffield wedges, and they vary wildly in size and angles. In my experience it needs to give enough of an angle to give the scales some flex and be wide enough to let the blade sit where you want it to in the scales (which, on a lot of old ones, is considerably higher than many modern rescales).

Thank you all...

I have a few calipers. Just trying to determine which measurements are the crucial ones. Your responses do help a bit..

Not sure how to take this part of your response Glen, but I suppose it's meant in a good way. [/shrugs]

Originally Posted by gssixgun

You are learning this all on your own

There seems to be some black magic that I haven't uncovered yet. I've read about sizing the fat side based on where the blade should sit. Sizing based on shank measurements seems more definitive. The rest sounds more hit or miss and is eluding me. Is it more trial and error or experience, than math?

Originally Posted by MikekiM

Not sure how to take this part of your response Glen, but I suppose it's meant in a good way. [/shrugs]


Is it more trial and error or experience, than math?

Yes absolutely, the more you take apart and learn from the easier it gets, Try measuring the wedge difference from the Inside (Toward the razor) to the Outside (away from the razor) and see what you find ... I did some measurements on one I just did a week or so ago here

Also note where I wanted the razor to settle, on that build I was aiming for the Notch to be just showing, much like they did in the old days

http://straightrazorpalace.com/custo...-all-horn.html

Thanks for the insight Glen, must admit all mine with wedges and the couple I have broke down appear to all be parallel vertically, but good to know this is not always the case,
I also have agree the more you play with the more you learn. Cos reading and talking about it doesn't teach me as quick as doing it.
"It is best to learn from others mistakes as life is to short to make them all yourself "