-   How To's and How Do You's (
-   -   Fitting Bolsters To A Full Tang Knife (

Cybertrix 27-04-2010 05:34 PM

Fitting Bolsters To A Full Tang Knife
After my last knife someone asked about how I do my bolsters so here is part one.

I am making a stalking knife that will have brass bolsters so this is how i do them.

Having made the knife to the point of it being hardened and tempered I will make the bolsters before I finish the polish on the blade. I drilled the holes for the pins when I was making the knife so make sure you decide which size pins and materials you are going to use before you do the HT.

I will be using 4mm brass pins and 6mm brass sheet, I have found that for my size knives the 6mm brass is ample.

Clamp the knife to the brass on the drilling machine so you can drill the first pin hole. Give yourself planty of room, 3 or 4mm bigger than the bolster will be, in case the blade moves a little while you are drilling. Make sure the drill bit is sharp and you have the right drilling speed.

This piece of Brass was cut on a guillotine so the edges have rounded corners and may not be very flat. Before I drill the holes I flattened the underside by rubbing it on some corse wet and dry taped to a flat surface. If your material has been cut by saw this step may not be needed but check.

After you have deburred the hole, take a piece of pin stock and put it in the hole and the knife so it holds the two holes in position. Clamp the knife again and drill the second hole. If there is a third hole do the same again so you keep all the holes lined up.

Use the pins to locate the blade while you scribe the profile of the knife onto the brass.

Scribe both top and bottom outlines.

Decide how big you want the bolsters to be and what shape the will be, mark them out on the blade with a marker so you can get an idea of what you want before you cut them out.

Now using these marks, transfer them to the brass so you can scribe them before cutting them out.

Use a can or other object of the required shape to get a good line.

Now you have the bolster marked out on the brass with the holes in the right place.

Using a hacksaw cut the bolster out and refine the shape a little with files. Be carefull not to cut too much off or you might have to start again.

After you have refined the shape, deburr the edges and make sure the face of the bolster that sits against the knife is flat. I use the wet and dry taped to a flat surface method again.

Now make your second bolster in the same way as the first.

Put the pins in place to line up both bolsters and clamp the in a vice. We don't need to worry about the top and bottom edges just yet but we have to make sure the riccaso edge and the handle edge are filed level and polished smooth.

The polish need not be to the final finish as there is still more work to do just yet, I go to 400 grit.

The edge that mates with the handle material MUST be flat and square, unless you are doing dovetailed bolsters of course. :rolleyes:

Now I try them for fit before I give the blade its final finish, after which I will tape up the blade to protect it before we anneal the pins and fit the bolsters permanently.

After I have polished the blade I will take some more pictures of the last stages.

Bernie Garland 27-04-2010 05:48 PM

Excellent post John, it will be made a sticky :thumbsup:


bigkev 27-04-2010 06:09 PM

great stuff... cant wait to see the finished article...

bushwacker bob 27-04-2010 06:32 PM

As usual John, a well written and easy to follow tutorial with great pictures.

digit 27-04-2010 06:49 PM

Thank you for an excellent tutorial :thumbsup:

Mike Bowler 27-04-2010 07:16 PM

Excellent post John

Cybertrix 28-04-2010 03:30 PM

Now for part two.

I have polished the blade to it's final finish and taped up the blade to protect it. I have annealed the brass pins so they have changed colour and will need to be cleaned up before they will fit in the holes. I just use a piece of 400 grit paper and give them a quick rub.

How to anneal brass, well I was told to gently heat the brass untill it turns golden brown and cool it rappidly. Most people treat it like copper and heat it until red and quench. I have tried both methods and they work equaly well. When working with pins it's hard to heat the whole pin and it has to be quenched quickly. I have an old pair of cheap needle nosed pliers that I can hold the middle of the pin if it's a very small one. The easiest way is to rest them on a fire brick and heat them gently so the gas torch doesn't blow them away, when they are red hot flick them into a container of water. If you miss the water, don't try to catch them. :lol2::rolleyes:

Now is the best time to polish the front of the bolster, put the pins through them like before so they are polished equaly. The outside of the bolsters will need the holes chamfering, not too much on this knife as the bolsters will be staying close to the size they are now.

Now put everything together, if you have been accurate with the drilling, the pins will be reasonably tight as we have rubbed them up after annealing. I like to leave about 2mm of pin protruding from each side. I start hammering with the ball end of a ball pein hammer around the edge of the pin. Do a little on each side to start with, don't be too gentle as I have found that the brass will work harden very quickly. The more times you hit it, the sooner it will crack and if a piece breaks off you might be left with a small void. After I have them mushroomed I hit them hard on top with the flat of the hammer 2 or 3 times only.

Now I make sure the fit is OK and the bolsters are tight against the knife.

Now I gently nip them in a vice and file them down flat.

Then I flaten them off with some coarse paper taped to a flat surface.

This is all the finish they need for now, I like to take the profile down to the steel of the knifenow but I shape them after the handles have been fitted.

I hope this helps anyone whos interested in trying.

Opal 28-04-2010 04:29 PM

Loads of respect to you for this fine tute, enjoyed it. :thumbsup:

Bernie Garland 28-04-2010 04:40 PM

Top Man John,brilliant Tutorial :thumbsup:


scruff 28-04-2010 05:14 PM

Superb tutorial sir.

Just wondering about the need to anneal though. Its possible to buy brass soft or half hard isn't it?

All times are GMT. The time now is 09:48 PM.

Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2020, vBulletin Solutions, Inc.