Do you drill pin holes 1 size up?

C

cubegleamer

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Feb 3, 2011
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I've seen a couple of YouTube videos where the knifemakers will drill the pin holes in the scales 1 size up from the pin size when using Micarta or G10.
I've been afraid to try this because I really want the pins to look like they're nice and tight on the scales. I don't want to see any gaps. However, I am really struggling when taking the knife apart during mock-up. How many of you drill your pin holes 1 size up? Have you had any problems with the fit and finish?
 
Yes! For instance, I use an "F" drill to make .2570" holes that will accept a 1/4" (.250") bolt. Those extra couple thousands allow easy fitment and they do not cause a big nasty glue-line when the handle is all glued-up and finished.

You can google a "drill chart" online, just select the next size up from whatever pin or bolt you want to use. Again, a few thousandths of an inch is all the clearance you need.
 
Always larger through the steel. Sometimes through the wood. Often I will drill the nominal size through a scrap of handle material and see how the pin fits. Then either drill 1/64 larger or sand the pin a hair thinner for a good fit if the "nominal" sized hole is too tight. I have cracked more than one set of scales trying to mock up the blade and handles (or get them apart after mockup). Which of course sucks.
 
You could ream the hole slightly with a round diamond file to give you a nice smooth slip fit.I usually notch the center of the pins as well.Harbour Freight sell the files cheap.I'm sure my ways not the best, but I also like a fairly snugish fit.No problems so far but I do use a high quality marine epoxy,and multiple pins.Good luck. Lu.
 
F drill for the 1/4" as James said and a #30 for a 1/8th. These are the two sizes I use most of the time.
 
I will sometimes drill slightly oversize in wood but never in micarta or G10 and I don't do any mock-up on standard fixed blades with bolsters (I don't do any non-bolstered fixed blades). The knife goes together one time with epoxy and I usually have to lightly hammer the pins through the synthetic scale materials. The reason I don't like anything oversized is because of the bolsters; it is too easy to get a gap between the scale and bolster material if any holes are over-sized. Everybody has different techniques, you have to find what works for you.

Bob
 
Horsewright said:
F drill for the 1/4" as James said and a #30 for a 1/8th. These are the two sizes I use most of the time.
Click to expand...

Yup! I would add a #12 (.1890") for 3/16" Corby bolt shafts and an "O" (.3160") for 5/16" thong tubes. Add a larger drill for knocking holes in/taking weight out of full tangs, and you can do all your knife work with just five good bits. Buy two of each size, and get the best. There's no need to buy a multi-piece set with lots of drills you'll never use.
 
In the handle scales, I like a smooth slip fit...not tight - not loose.

In the tang I go 25% to 50% oversize to make alignment simpler. That sounds like a lot, but on a 1/8" pin or bolt shaft, 50% oversize only allows only about three one-hundred's of an inch clearance ( 0.030"). On a 1/4" pin with 25% oversize, the clearance is the same 0.030".
For reference, 0.030" is about the thickness of two business cards.

Trust me, when drilling three holes in a tang, there can easily be that small amount of drift and misalignment. When assembling the handle, one bolt/pin will not go through without some wiggle room.( Raise your hand if this has happened to you :))
 
I was wondering something similar lately. Do you drill a size or two up in the tang as well? Seems it would let you adjust your scales easier against the bolster, but then you are relying more on the epoxy adhesion for slippage.
 
That is the point why I drill the tang oversize by 25-50%. Once the epoxy is cured, it will be rock solid and tight. A good grade epoxy is as strong as the wood.
 
Here is something ya'll might be interested in trying. When you get the pieces ready for final assembly freeze the pin before slipping it into the holes. I am an aircraft mechanic working in maintenance & restoration of WW2 aircraft and it's one of the tricks we use for dis-assembly & re-assembly of 70 plus year old 'they don't make'em anymore' parts. We can't afford the risk of breaking an irreplaceable part inserting a pin or putting tight tolerance parts back together. So what we do is either flash freeze or put a part or pin in the shop refrigerators freezer for several minute so that it will cool down and shrink enough to drop in the hole or assemble without forcing. When it warms back up the pin is tight fitting and will not come out.

I also use a cans of 3M Freeze Spray to flash freeze pins while holding the pin with needle nose pliers.
 
Stacy E. Apelt - Bladesmith said:
In the handle scales, I like a smooth slip fit...not tight - not loose.

In the tang I go 25% to 50% oversize to make alignment simpler. That sounds like a lot, but on a 1/8" pin or bolt shaft, 50% oversize only allows only about three one-hundred's of an inch clearance ( 0.030"). On a 1/4" pin with 25% oversize, the clearance is the same 0.030".
For reference, 0.030" is about the thickness of two business cards.

Trust me, when drilling three holes in a tang, there can easily be that small amount of drift and misalignment. When assembling the handle, one bolt/pin will not go through without some wiggle room.( Raise your hand if this has happened to you :))
Click to expand...

HAND WAY UP!!! Drift indeed... also it seems every time i send soemething out with exacting fit it is a little tighter once it's heat treated... maybe i'm wrong but it often seems the case (anyone coment on this?) i also have never heard of "F" bits or "o" bits or #12 bits. have i been missing this all along? where do you guys get these and how do i find em?

Much appreciated
 
well don't I just feel the idiot on this one... all I ever look for is metric and imperial. Alpha numeric has just started me on a new quest for adventure... and possibly easier fitting handles with slightly less arse pain
 
Depending on alloy and HT procedures, steel can change dimension a bit during austenizing and quenching, too. On knife-size pieces this change is usually so small it's difficult to even measure, but you'll notice it when you get some blades back from HT that fit together perfectly in mock-up... but now need one or all the holes reamed. :mad:

Having a little wiggle room may be even more important when using peened pins... it hasn't happened to me yet (knock wood) but other makers have described cracking/splitting and even lifting the scales right off a tang when a soft pin swells from peening, and has nowhere else to expand.
 
yep... i seem to have to use a diamond file a fair bit after ht to get my pind to fit... looking into this new (to me) to hopefully cure this and save me that 20mins per knife. also knock wood ive never split anything peening as of yet either.
 
I guess I'm in the minority here, but I typically just grab an 1/8" bit for 1/8" pins, and 3/32" for the same size pin. Granted, I also chase with a tapered pin reamer and peen my pins, so there's really no reason for me to start with a larger size. That said, before reaming, I've never had issues with fit up. If doing a set of scales, whether fixed or folder, I'll put a couple of drops of super glue in between them to keep them together, then clamp to my already drilled blade tang, back spring, or what have you. Holes line up exactly every time.

Now, for a lot of my fixed blades, I also just use corby bolts with a corby drill bit. No muss, no fuss.
 
knife to a gunfight said:
I guess I'm in the minority here, but I typically just grab an 1/8" bit for 1/8" pins, and 3/32" for the same size pin. Granted, I also chase with a tapered pin reamer and peen my pins, so there's really no reason for me to start with a larger size. That said, before reaming, I've never had issues with fit up. If doing a set of scales, whether fixed or folder, I'll put a couple of drops of super glue in between them to keep them together, then clamp to my already drilled blade tang, back spring, or what have you. Holes line up exactly every time.

Now, for a lot of my fixed blades, I also just use corby bolts with a corby drill bit. No muss, no fuss.
Click to expand...

I always have great luck with corby or loveless bolts as well, and never had a problem as i do drill those a fraction larger... I also CA glue scales on when shaping and sanding prior to fit up. Problem i always have is on 1/4" and 1/8" holes that i am using brass tube with for making flared tube style handles as i do on my parachute knives. part of it is that the holes are super tight and of course the other part is that it's hard to get them that preceice (ie: 3 preceice holes with 3 tight fitting thin walled tubes = squishing a few tubes trying to get things tight). I don't want my scales to wiggle if the epoxy ever gives so i try to make the mechanical fastening as tight as possible. I have been fixing this by using 2 1/8" hidden pins to keep things tight and filing the 1/4" holes out a bit, but i think the "slightly oversize" drills that james and Stacy mentioned will be my new standard. Here's hoping i save 20 mins per knife... fingers crossed
 
Always. I finally bought some slightly oversized bits earlier this year after being told to do this for years. My knife making satisfaction has greatly increased. Really helps me with tapered tang fit up.
 
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