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Bolsters, where to begin?


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Ok, so my newest question of the week. Bolsters and bolster material.

 

I've been looking all over the internet for matching stainless bar and round stock--no luck. Apparently 416 comes in bar and 410 comes in round. 304 was floated by me as an option, but machinability is poor unless you want to pay extra for some added element (I forget which). Is there a stainless out there that solves this problem of machinability and material matching? If not, are 410 and 416 close enough that you wont be able to see a difference?

 

Next, I went to my local steel recycler and bought some scrap copper and brass. I recently finished my first bolstered knife with copper bolsters (see image). Three questions came of this:

 

1. Copper and brass are both very heavy, which led to an inordinate amount of weight on the bolster. This feels clunky at the bolster, and makes the blade feel dinky. Does bronze or stainless solve this issue?How thick do you normally make your bolster stock?

 

2. At the wood/copper intersection, there is a thick (.050" ish) layer of epoxy. I used standard J-B Weld. What epoxies do you use? Are they translucent, do they spread more to avoid such a thick layer? In short, how can I avoid this next time?

 

3. The close-up of the bolster shows a ring around the pin used to secure the bolster. Again, I think I blame the epoxy, but I look forward to suggestions on solving this issue moving forward.

 

Thanks for the thoughts!

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I've never used 410 for anything, but the 416 I buy does come in round stock form from McMaster, but I'm not sure they have it in flat stock. Either way, I don't think you would be able to tell the difference between them if you mixed them on the same knife.

 

You won't find bronze or stainless to be any lighter than the brass or copper. I tend to taper my bolsters forward to reduce the weight a bit. By the time everything is shaped, they tend to come out at about 1/4" at the thickest part, and about 1/8" towards the blade.

 

Controlling the epoxy lines is all about controlling the gap when the parts are assembled dry. If you dry fit everything before using epoxy, and can't see any gaps, then there won't be any once to glue it all up. Not sure what epoxy I use. It is a 2 - bottle kit I bought from a knife maker supply place. It is quite a bit runnier than JB Weld, and much easier to work with. I can see how you might have a hard time trying to squeeze excess JB Weld out of a joint.

 

The ghost ring around pins can be a bit of crap shoot for me. The most important thing is for the pins to be a light press fit. The best advice I ever got about this came from a guy on the model steam engine forums who's pins in his models are always invisible. His advice is to drill the hole, and then do absolutely nothing to the opening. Don't sand it, don't deburr it, don't touch it until you put the pin in.

Edited by Brian Dougherty
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I use 416 all the time. USAKnifemaker.com normally has it in both flat and round.

 

Edit: I find that cleaning my pins outer surface with 0000 steel wool and denatured alcohol helps to reduce the dark ring. As an add to the above procedure.

 

 

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Edited by GBrackett
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I switched from JB Weld to G-flex marine epoxy, after someone else recommended it on a previous thread. I have been very happy with the G-flex. It flows much easier into hidden tang knives and the little bit of translucence helps blend any gaps, but a tight fit is the only way to avoid that completely.

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775

tight fittup will make for less to no noticeable lines between elements on a handle

 

it looks like the pin or pins used for the bolster are huge you don't need a large pin to hold them on and three pins always align a piece better than one or two pins will were four is just asking for trouble when fitting up bolsters

 

i like to use a new drill bit or one that hasent been used for ruff shop work

that minimizes the warble/wander when drilling in or threw materials a dull bit will always make a bigger hole than a sharp bit and you might not see it till the final grinding and polish in metal your more likely to see that than in wood

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Plus it's essential to use exactly the same alloy for the pins as for the bolsters. Nickel silver is especially bad for sheet stock and rod stock being slightly different in color after a little age. Brass can be that way too.

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