Full tang scales not lining up

S

Skiller1nc

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Jun 27, 2016
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Working on a set of hunting knifes. I'm trying to attach handles and I'm having issues. I have 6 hardened blades with pin holes already drilled. I numbered each blade and each set of matching micarta scales. I flatten the scales and then super glue the scales together and then super glue to one side of the knife. I drilled (drill press) all 6 pin holes on each blade, adding 2 pins, one at each end and edge/spine side as I drilled to keep the blocks from shifting. I cut out the handle outlines and finished the fronts to prepare for glue up. Here coke the problems.

None of the handles now mate to the knifes. Some holes are canted, even though the drill press is square in both dimensions and my handles were parallel to each other and perpendicular to the drill bit.

Some holes don't even line up, if I put in one pin, 1 or 2 of the resulting 5 others holes are off by almost a pins diameter.

The pins don't fit in the micarta after drilling neither does the drill bit, it's like the holes shrunk. But I don't have a one size up bit for .094", so I can't even dry fit handles bc it takes a press or hammer to insert pins to the micarta and this has been bending my pin stock.

I tend to stick to hidden tang and I'm really remembering why that is but is there a step of my process that's sounds off that I can change to fix this or something y'all see that's wrong?
 
I'm not a maker just a fiddler but . . . I have successfully done it this way, so some angles gotta be off somewhere. Drill press table is canted,? Or maybe the tang or the scales aren't 100% parallel? Have you checked them all with a level and micrometer?

If you used a lot of glue that could also affect the angles, but it would take a lot . . .
 
Is this a tapered tang? If so you will need to put your knife blade in a fixture so that the flat of the taper is exactly square to the drill press. If no taper then re-check all your angles with a known good square. I reserve a really nice square for just this purpose.
 
fishface5 said:
I'm not a maker just a fiddler but . . . I have successfully done it this way, so some angles gotta be off somewhere. Drill press table is canted,? Or maybe the tang or the scales aren't 100% parallel? Have you checked them all with a level and micrometer?

If you used a lot of glue that could also affect the angles, but it would take a lot . . .
Click to expand...
It was just a few drops of glue nothing to change angles and i guess the scales could be non parallel, I need to measure them.
 
seanj said:
Is this a tapered tang? If so you will need to put your knife blade in a fixture so that the flat of the taper is exactly square to the drill press. If no taper then re-check all your angles with a known good square. I reserve a really nice square for just this purpose.
Click to expand...
I used a machinist square to check the drill press before I used it.
 
You mention that it's possible the scales are non parallel. What I do is tape a piece of sandpaper to a my surface plate and then sand the scales flat. That ensures they are totally flat..
Hope that helps
 
Jobber length bit wandering?
I prefer screw machine length bits.
 
seanj said:
You mention that it's possible the scales are non parallel. What I do is tape a piece of sandpaper to a my surface plate and then sand the scales flat. That ensures they are totally flat..
Hope that helps
Click to expand...
This is what I did, I guess what I'm saying is even if I do both sides and they are flat it doesn't mean they are parallel.
 
fitzo said:
Jobber length bit wandering?
I prefer screw machine length bits.
Click to expand...
I guess, but on a .094 bit does it make a lot of difference, it's going to flex no matter what? That said, i was staring the hole with the tang holes supporting the bit, ie drilling through those holes so it shouldn't be able to wander
 
Micarta can shrink back a bit from what I have seen, so I always make sure to drill it twice and make sure the dust and debris is out. Did your scales get flipped over, ie the 2 sides that were together when they were drilled are now apart? I always make the holes in the tang bigger than the pin and use an oversized pin to make sure there is a good fit. 1/8" pin doesn't fit into a 1/8" drill bit hole; the hole usually needs to be reamed or slightly oversized (ie use a #30 drill bit for a 1/8" pin). Not sure what the oversize bit is for .094", maybe .100"? With a bit that thin, I am guessing it is flexing a bit while drilling? Can you enlarge the holes in the tang (Dremel works well for this usually, depending on the steel) or are the holes in the scales off from each other? I clamp and drill, using the tang as the template, adding pin stock to the holes after they are drilled. If I need to reclamp, I clamp everything in place with the first clamp on, get it tight, make sure the pins slide through freely like they should before removing the first clamp. I stack up my scales and clamp them together to the tang before drilling, using 1 C Clamp.

Superglue will make the scales sit unevenly and you need to sand the glue off of the tang and scales and it's possible to make things not flat a parallel doing this, too.
 
Gah! Don't sand super glue off, for that very reason - instead hit it with acetone and it will soften and then cut/scrape it off with a razor blade
 
Your drill bits flexed and walked. You have already been given the answer above by Devin

A 1degree deviation over an inch is .017” off. So if your drill wandered even half a degree, your scales alignment will be off.

Don’t drill the scales stacked
Use stub length drills
Finish with a reamer if you can, I believe it’s a #41 for a 3/32”

and yes absolutely a .094” drill will wander even using the tang hole as a guide
 
This might seem like a stupid question, but did you mark left/right and glue the scales inside to inside? I also superglued last couple of scales and didnt have any problem with it.
 
Skiller1nc said:
Some holes don't even line up, if I put in one pin, 1 or 2 of the resulting 5 others holes are off by almost a pins diameter.
Click to expand...
This is impossible if you do everything as you say ...........Maybe somehow you mixed scales ? Are they are same color ? Do you have pictures ?

Drill one hole , insert pin , drill other hole insert pin , drill other hole insert pin .....drill all other hole ..........job done .
Cooper pins , peened
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This method 100% guarantees all pins will align when reassembled.
Here is how to avoid the issue:
Glue or clamp one scale to the tang.
Drill the holes from the tang side, placing pins through the holes as you go.
Remove the pins and clamp/glue the other scale on.
Drilling from the already drilled side, drill through the second scale, placing the pins in the holes as you drill.

Other tips -
Drill the tang holes 15-25% oversize. This prevents binding when inserting the pins.
Use sharp and short drill bits.
The pins should slip through smoothly, not tight, not loose. Select the right size bit and use a reamer if necessary.
 
FredyCro said:
This might seem like a stupid question, but did you mark left/right and glue the scales inside to inside? I also superglued last couple of scales and didnt have any problem with it.
Click to expand...
Yeah I obsessively mark everything, inside, outside, what blade it matches etc.
 
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