Cutting the slot on a slotted guard?

[Jason Fry]

I've done a bunch of guards on a knife with shoulders, like on an ABS style knife. I'm having fits with a slotted guard, where the guard is cut all the way from one side and pinned. What's the best way to cut the slot where the sides are parallel and square? I've boogered up two or three lately by using a mill to relieve the back and file fitting like a pressed guard on a stick tang. Having trouble getting the fitup acceptably tight while also getting the pin hole to line up. I'd like to be able to essentially press fit it rather than trying to fill a gap with solder, another technique I haven't any experience with.

 

[Willie71]

I mill it slightly undersized. I mill a slightly oversized slot in the back but don't go all the way to the spine. Carefully file to fit. I drill the pin hole in the tang oversized, but tight between the guard and pin.

 

[HSC ///]

Are you using a .002 undersized press fit on the slotted guards?


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[Jason Fry]

My mill's not that precise, Harbeer, nor is my filing. On a stick tang guard, I typically can peen the edge of the slot in a little if I end up oversized.

Willie, I can see how the pin hole oversized in the blade would be helpful... next time. I'm only using a 1/16" pin in 1/4" stock, not much margin for error.

 

[john april]

sounds like you are doing a loveless style guard ? you boogered them up on the hand file fitting or the milling part? i have a bottom of the line grizzly mill, and i mill the slot out one thousandth of an inch wider than the tang, measuring with dial calipers. with my mills slop/error it usually ends up about 2 thousandths bigger but it is a nice close fit. if i am doing a flat ricasso edge instead round, i use a blind file, it has all the teeth ground off the faces, only the sides cut. that way you do not dig into the sides of the slot you took so much care to get a nice fit. once it is fit, i clamp needle nosed vise grips around the open side(spine) of the guard so it wont move, clamp the guard in a drill press vise and drill the pin holes.

 

[MBurks]

I have been searching around for this very thing. I want to do a Loveless "inspired " guard for a few hunting knives and want to avoid any potential pitfalls if I can.

Is there a good WIP somewhere relative to this style guard/bolster?

 

[MBurks]

I don't have a mill, I'm sure it's possible with hand tools right?

 

[Jason Fry]

I have a Rong Fu 31, but I have no real education with it other than trial and error and some youtube. I ended up on this knife using one of my earlier attempts and soldering. I've not soldered a guard before, but I have done stainless bolsters to stainless liners for slipjoints, so I have the right solder and flux. After three tries, I think I got it acceptably cleanly soldered.

Is there a precision way to do this? I envision a surface ground ricasso to an exact tolerance, then some kind of slitting saw to cut a dead-nuts straight slot at the exact same tolerance?

 

[J. Doyle]

I'd do exactly as John April mentioned.....drill the pin through the guard and tang all at once...after the guard is fit.

You must have got a dud with your mill.....or I got really lucky maybe....my RF 31 is amazingly accurate. Much more than I expected. Though I had heard pretty good things about them before I bought mine, for what we knifemakers do with them.

 

[HSC ///]

I have a Rong Fu 31, but I have no real education with it other than trial and error and some youtube. I ended up on this knife using one of my earlier attempts and soldering. I've not soldered a guard before, but I have done stainless bolsters to stainless liners for slipjoints, so I have the right solder and flux. After three tries, I think I got it acceptably cleanly soldered.

Is there a precision way to do this? I envision a surface ground ricasso to an exact tolerance, then some kind of slitting saw to cut a dead-nuts straight slot at the exact same tolerance?

Jason have you checked the accuracy of your mill by making cuts and measuring? Is everything clean? and swept and Indicated in? Do you know the basics of how to square up a block? How square Can you get it?

I think you need to know about the equipment you are working with if you want to get everything out of it.

We Are milling small slots in soft material. You should be able to get within .002 on your slot for a press fit.


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[Jason Fry]

That's the issue. I've not even got the basics down for the kind of checking that's necessary. I agree entirely that the equipment is more limited by me than I am by the equipment.

 

[mknife]

Jason,

this is my way, excuse my English help me with Google translator

Help me with the band saw, cutting due parallel lines that end up in the hole.

I finish with the milling machine, bringing the internal measurement to be 5 cents greater than the thickness of the blade plate (at this stage (pre HT) of the blade plate is worked to 600 grit).

I put the guard, it is often necessary to force the entrance but the result is good. The guard already has the side toward the blade polished or otherwise finished

therefore realizable the hole for the insertion of the pin that will stop the guard on the handle

After HT, I finish the blade, mount the guard (am slightly conical hole on both sides of the guard) and I say the plug.

I prefer not to solder the guard, if everything is done right the space between guard and blade is invisible. Another way expected to finish the blade make the hole for the passage of the guard pin, then HT the blade...finish the blade and then realizes the guard. In this second case it is necessary to pay great attention to make holes on the guard so that they are corresponding to that done on the blade.

the result without soldering is this

______________________
Riccardo Mainolfi

 

[Jason Fry]

Nice tutorial, Riccardo!

I've solved the problem for the knife in question. For next time... Fit the guard and drill the hole before heat treat. And learn to use the mill.

 

[Charles Vestal]

Jason,

Get a small piece of stock the same thickness as the knife you are working on and use this piece to check how close you are on your slot. This is a lot easier than taking the guard out of the vice and having to make sure you have everything set up as before if you have to take a little more off.

Take care

Charles

 

[Jason Fry]

Good idea, Charles.

Here's what I ended up with this time.

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[Karl B. Andersen]

You should be able to get within .002 on your slot for a press fit.
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With a dial indicator on the side of the table, I can get within .0005". And I have a round column Griz.
I'm thinking he just needs to keep at it until he learns the machine.
This is right off the mill, no back-cut on the ricasso - tapped into place after relieving the slot ends.

 

[HSC ///]

With a dial indicator on the side of the table, I can get within .0005". And I have a round column Griz.
I'm thinking he just needs to keep at it until he learns the machine.
This is right off the mill, no back-cut on the ricasso - tapped into place after relieving the slot ends.

Same here. Right off the mill.
Cold press fit. No solder or jb weld required
Gap less than .001

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[Karl B. Andersen]

Find the center of your guard slot with your end mill.
Place a dial indicator on the side edge of your table and place it on zero.
Measure the thickness of your knife.
Subtract the diameter of the end mill.
Divide the remainder by two.
That's how far on either side of the center line you need to go.
Go that far.
Tap it on.

 

[Jason Fry]

thanks, Karl. Been watching a bunch of youtube, learning simple things like how to use an edge finder, how to square up a vise, etc. Getting closer, and getting a pretty long tool list again.