Attaching a buttcap *UPDATED WITH PHOTOS PLUS FINISHED KNIFE*

jwesthurl

jwesthurl

Joined
Sep 17, 2013
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430
I'm trying to figure out the best way to attach a wrought iron buttcap to a hidden tang knife with a bog oak handle. I've come across a few ideas but I'm looking for a little advice on what might work best. I can't tap holes and I'm probably not going to be soldering anything, so what are my options?

*****UPDATE*****

Here are some photos of my solution plus images of the finished knife

1/4-20 bolt sans head welded onto the tang
i-SbRz7VZ-L.jpg


Here is the tapped buttcap, the 1/4-20 tap and the modified tap for tapping the blind hole
i-X9dLPZw-L.jpg


The finished knife: My take on an ancient Irish scian
The knife is part of a raffle for the 20th anniversary of the Metropolitan St Louis chapter of the Emerald Society which is a fraternal organization of Irish police officers
13" overall, 8" blade
1084 with bog oak handle, wrought iron fittings and G10 tricolor spacer
Emerald Society pin inlaid in the handle
I antiqued the blade with salt and vinegar then an etch in FeCl
i-CcG37Bh-XL.jpg


The knife on the custom stand inlaid with an Emerald Society challenge coin
i-Sd4wP8D-XL.jpg


Closeup of the guard and spacer
i-rNbSf9p-L.jpg


The infamous buttcap!
i-rvzTTfH-L.jpg


Thanks again for all of the help and advice from everyone!
 
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Peen it?

~Chip
 
Hard solder a barrel nut or cut down corby on the cap and either thread the end of the tang or fabricate a clevis using a piece of bolt or all thread. That is if you want a hard connection. Another option is to came the tang about 80% of the length of the handle and with the other 20% hard solder a little "tang" to the buttcap and secure both with epoxy from each end. A possible third option would be to make the tang reach the end and then secure the buttcap with "registration" pins and epoxy. if you can't or wont tap or solder, then peening may be your only option. With that said, the simple tap and die see sold at Home Depot and Lowes are more than sufficient for this purpose. You can even drill through the cap, thread it and peen the stub or just grind it flush.
 
It's not a through tang so I can't peen it. The idea I'm leaning toward is drilling two blind holes in the cap and matching holes in the butt and epoxying everything together with threaded rod in the holes. Is this a good plan?
 
Only if you're threading the holes in the butt cap. Or they will be significantly deeper than I imagine.
 
It's really better to have the tang extend, and attach to, the buttcap. You can make a tang extension pretty easy... by brazing or other methods. If you use threaded rod as your tang extension, that makes it convenient to fit a butt cap to it by one of two or three methods.
I don't plan a butt cap on a knife unless the tang extends all the way to it...
 
I made the turquoise into a donut by using two different size hole saws. I drilled two holes through the turquoise and end of the handle. The brass cap was a toe button from an old piano peddle . It has a ring of " fingers " that held to the only peddle. I epoxied the turquoise under the knife handle then filled the hole of the doughnut and set the brass button into that. This is my personal Knife and it has remained a good tight fit.

Having a tough time posting pictures ...... Maybe I'll figure it out later.
 
Just out of curiosity, what prevents you from drilling and tapping the pommel?
 
Whenever I do a buttcap, I'll braze a piece of threaded rod on for last inch or two of the tang, and have the buttcap screw on.
I'm not sure why tapping a hole would be an issue. You can buy a single industrial quality tap in the size you need from either a local industrial supplier or a machine shop supplier such as KBC tools. In the sized I'd use for a buttcap (1/4-20 or 5/16-18) you'd be looking at $10-15 for the tap, and it would be a real high quality tap that will work well, rather than hardware store cheese grade
 
Ok so you guys have me rethinking this, lol. The reason I wanted to avoid this was because I've never tapped blind holes and I don't know how to braze or weld.
For this knife it seems the easiest way to do this would be to attach threaded rod as an extension because it's a straight tang and I do have a 1/4-20 tap. Can anyone point me to clear instructions on how to attach this extension to my tang? Do I just need a torch and brazing rod? Also, will a blind hole work in the buttcap (will it be deep enough)? The wrought iron I have for the cap is approximately .40 in or 10mm.

*Edit* I just reread jdm61's post about soldering a barrel nut onto the cap. Would that be easier than trying to tap a hole?
 
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Tapping a blind hole in a buttcap is always gong to be a bit trickier than one going all the way though. Brazing is not that hard IF you have shot enough torch. Since you are gong with a thick buttcap, you could drill a hole the diameter of the barrel nut or corby head about halfway deep or more, so that you had good support for your nut.
 
Blind holes difficulty depends on the depth. If it's super shallow they can be tricky. If it's a reasonably thick buttcap it should be fairly straightforward provided you don't accidentally drill too deep.

As for attaching the rod I usually braze it with an oxy acetylene torch and a bronze brazing rod. Silver brazing works too, and is an issue of preference more than anything.
If you don't have oxy acetylene, you could potentially get by with an air acetylene turbo torch, but hard silver solder on fairly thin pieces is about the limit for those in my experience.
 
The only torch I have on hand is a MAPP torch which I'm guessing isn't going to be hot enough. I may have to ask around and see if I can get some help.
 
If your tang is thin enough and you use something like 45% silver solder rather than bronze brazing rod, it might do it. I've just never had that much luck with them for anything beyond soft low temp solder
 
Even low temp solder would be preferable to epoxy imo.

If it where me I would drill a shallow hole in the butt cap, the size of the large diameter head of a female corby bolt, and solder a copper or brass one in there, then solder an extension on the tang, or, if the tang was now long enough due to the extended reach of the corby, just thread the end of the tang for the corby. You don't have to use a corby, but it's an easy standoff most people have on hand. Other standoffs if purchased are covered in zinc or other coatings that you have to clean off to solder, and it doesn't sound like just making a steel standoff from scratch is something you want to do.
 
Thank you all for the help and opinions. I'll have to figure out a plan with what I have. I do have one more question regarding assembly with a threaded tang. Do you still assemble with epoxy or just tighten everything down with a little thread lock?
 
How long is your tang compared to your handle? It would be helpful to see a picture. The one thing you need to keep in mind is once you mechanically attach the butt cap to the tang it will be fixed at what ever angle you set. So if you braze/solder/weld/tap at some funky angle then the butt cap will sit at that angle. This is one nice thing about forging, just draw the tang out full length and forge round. Shape the tang to the curve of the handle and then run a die over it. Thread the cap and done. But in your situation it all depends how far the tang stops from the cap. This is why a picture would help.
 
Cut a V in the end of your tang... for the purposes of this discussion, we'll use 1/4-20 allthread. Grind the end of the allthread to a point to it fits the tang V. Say a 1/2" long V. Assemble them together onto a firebrick, shimmed a bit if necessary to keep the joint centered and straight, heat a bit and flux (brazing flux, available in a plastic jar in the welding supplies most harware stores) or borax works OK. Heat more, bringing your 3/32" brazing rod into contact with the joint as it reaches a medium red, watching for it to start flowing. The rod will come either coated or not, in either case really I heat the end a bit with the torch and stick it into the flux jar to coat it with fresh flux before flowing it into the joint.
Make sure you've gotten enough metal into the joint to penetrate all the way through- you should see it wetting to the surface and getting sucked into the joint by capillary action. If it won't, try a little flux applied directly to the hot joint, more on the rod, or a little more heat. All of this should be done wearing shade 5 green torch filter or goggles.
Let it cool, grind to size. You should see a clean joint with steel and brass together, no voids.
The buttcap- drill it with correct pre-bit, setting your depth stop on the press so it drills a blind hole almost through, but leaving at least .040" at the bottom so you can shape or polish just a bit without worry. You can find taper taps or plug taps at most stores, but bottoming taps less likely. Use a plug tap ideally, in the drill press manually (no motor) to start tapping your hole straight, and continue in a vise by hand, or make a hand tapper out of an old drill press, or buy one. Tap until the plug tap bottoms out. If you couldn't buy a bottoming tap, make one out of an old snapped tap or a new one- grind until the taper is gone, keeping it cool, then taper again on the grinder, just a bit, like one thread or two of taper, and then grind a little relief into the back of the tap flutes on the bottom two threads so they will cut (i.e. sharpen them from the back) and patiently finish your hole with that. You should be able to get your tang end into the buttcap by at least four threads, but do also epoxy. If misalignment is evident, you can carefully cold bend your threaded extension usually to adjust a little.
MAPP will be hot enough. I've done a fair amount of brazing with MAPP although I use oxy-ace in my shop for this.
You can make your allthread a bit long, try-fit to the buttcap when threaded, then grind some off the allthread until it fits up tight.
 
Quick update- so with all of your great suggestions I ended up welding 1/4-20 thread to the end of my tang. I drilled a blind hole in the buttcap and tapped it with a modified tap like Salem described. It needed just a little bend to sit perfectly. THANK YOU all for helping me with this. I'm definitely saving this thread for the future. I'll post pics when I can.
 
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