Files for guard slot?

[Runthemall]

What files do you use for a 1/8 inch slot? I'm making my first hidden tang knife, and my Harbor Freight needle files aren't working too well. I want a press fit. Is this too jacked up to be salvaged?

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[S.Alexander]

I use a flat chainsaw file. It came with a file guide (which I just threw away) and is only about .09" thick. I filed the sides to a taper so it fits in most of my guard slots. Another good thing about them is that they have smooth sides.

Here's an example of a similar one: http://www.chainsawspares.com.au/1-x-flat-file-depth-gauge-guide-6-150mm-chainsaw-f

 

[treewizzard]

needle files or a modified (ground down to fit the tang slot) file is what i use. you can taper your tang to get a better fit, if your tang is 1/8" all the way and your guard fits a little loose when you put it on the tip of your tang its going to be lose at the shoulders of the blade. with a tapered tang the hole for the finished guard is larger than the end of the tang so the guard goes on easier and while you are sliding and fitting the guard up the tang it gets tighter gradually and you slowly remove material instead of trying to make a really big hole with tiny crappy files all at once.

i think that a big problem with doing guards like this is the area of material being filed, the inside of a guard usually takes me a long time to file and its so easy to screw up the ridgelines at the edge of the tang slot, they have to stay sharp just like the ridgelines of a blade. there are a few more things i can recommend. finish the front end of the tang slot last, the rest of the guard has to fit but it doesnt have to be seamless so get the front close and jam it on if its copper/brazz/bronze i would finish steel or wood with a file, they dont seem to jam as well, if there isnt too much material left it should form to the tang. another thing you can do to make attaching guards is to drill out most of the guard from the back, maybe 3/4 of the way through, and then you only have to fit 1/4 the length of the guard.

if there is a gap between your tang and guard when its all finished up you can hammer around the tang slot to push some of the metal back into the tang slot and then probably press fit the guard, afterwards you will need to grind the front of the guard flat to get rid of hammer marks.

 

[Willie71]

For a better fit, use a 3/16" drill and drill 3/4 the way from the backside toward the front. You have less metal to file to fir on the front side then.

I use chainsaw files. You can even use the round ones if you grind a flat spot on the sides to get the correct width.

For needle files, go to Lee Valley. They are 4x the price of the harbour freight or princess auto files, but they work.

http://www.leevalley.com/en/wood/page.aspx?p=32950&cat=1,43072,43089

 

[i4Marc]

Runthemall,

I get cheap sets of diamond coated needle files at local gun shows. I use those and Harbor Freight/Sears etc. type sets of needle files as well. They work fine. As the others have said, drill the holes from the back side of the guard a little wider than the front. It doesn't need to be sloppy wide, just wider than the ricasso. Get the hole opened from the front with the needle files until you can get a 6" flat file into the slot. They are typically 1/8" thick. I get a handful of them at the big home stores. Use that to straighten out the lines of the hole opening. Easy does it. Take a few strokes and check your fit, repeat. Shoot for a press fit if possible on the first go. As the others mentioned the thickness of the tang should be SLIGHTLY tapered up until about 1/2" or so from the blade shoulders. Otherwise you will never be able to get a seamless fit. To get that kind of fit you need three things, the guard press fit along the sides of the tang, straight and flat blade shoulders, and well cut radii on the short sides of your guard hole. If you get the guard on very close to being seated but there is just a tiny gap left at the top, bottom or both the likely cause is not a smooth enough transition or radius from the inside of the guard to the face surface. Sometimes it takes very gentle strokes blending up onto the face surface to get that seamless fit you want. To make that happen you will want files with "safe sides". When you are new at this there are certain tools that raise your game to another level. A decent grinder of course, carbide-faced file guides and so on. Files with safe sides are one of those tools. Get yourself a few 6" flat files from your local hardware store. Take one of them and surface grind the teeth off the wide flat faces and leave teeth only on the thin edges. Be careful not to overheat the file while doing so. Now you can cut those radii in the guard slot without also inadvertently widening the slot. If you have filed the slot too large as in your picture, all is not lost. That gap is fairly large but you can save it if you are careful. Take a tack hammer, or a larger hammer and a medium sized pin punch to peen(Pein) around the edges of the hole. This will cause the surface to spread and start to close up the hole. You may have to do several rounds of peening to get the hole closed up sufficiently to allow a press fit. Again, easy does it. The bigger the dents you put in the guard face the more material you'll have to remove later to get it flat again.



PS. It's hard to tell from your picture but the corners where your tang meets the blade shoulders at the ricasso should have a small radius. This helps to spread out stresses. A square corner there is a no-no. This will cause a weak spot as the sharp corner will cause stress risers and may lead to failure of the tang.