Drill - enlarge pin holes in tang.

D

DeerWrangler

Joined
Feb 12, 2012
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As just starting out in wanting to do a little knife finishing i have been doing fine so far BUT i recently ran across a problem. Seems that sone of the knife blanks have pin holes of 2.5mm & 3mm instead of the standard INCH sizes.
Wanting to keep hardware more standard i want to enlarge ( drill out- ream out) those MM holes to accomodate " size pins.
Have tried using standard black steel bits then went to carbide bits with no real luck. tried using a Dremmil with diamond taper bits and not even that has done more than scratch the tang.

Seems that the knife maker hardened the whole knife the same temper as the blade.

So my questions are
#1. How can i enlarge the holes more easily, Anyone know of a tool- drill bit that will cut hardened knife steel.

#2. If i can not easily enlarge the holes & have to use MM size pins does anyone know of a place that carries mm sized pins?


#3. I could use bolts instead of pins BUT my problem still remains in that the 2.5-3mm holes are smaller than 1/8" and have to be enlareged irregardless of what pin-bolt i use on the handle.

Any and all guidance would be greatly appreciated.

Thanks
 
I agree with carbide reamers

but I would use them at a specific size.

If you want to use a 1/8" pin, then I would use an oversized .126, or the number size #30 .1285

and so on


you can only cut maybe 1/32 of an inch that way, so a tapered reamer to go up some sizes, then one to get on size...
 
You didn't mention what kind of steel you're using. If it is carbon steel, you could "spot anneal" the pin hole areas and drill them with a regular bit.
 
Or you could draw the tang back and make it soft enough to drill with a regular drill. What steel. Should be able to do it with a regular propane torch and the blade end of the knife in water or wrapped in a wet rag.
 
Count,
He wants to enlarge the holes in pre-made blades to allow free passage of pins and rivet shafts. If you only reamed with an exact size reamer, you would need a full set to make the holes various sizes. The tapered reamers I use are just tapered milling tools that will open up a hole in a heartbeat. If you don't clamp the work firmly,and run them fast enough.... they will break in a heartbeat,too.
I always recommend that the tang hole be 150% the rivet size. On a 1/8" pin the .180" tang hole will allow a tad less than .030" clearance all around. If you get the size too close, any mis-alignment will make things bind up.
 
12345678910 said:
I agree with carbide reamers

but I would use them at a specific size.

If you want to use a 1/8" pin, then I would use an oversized .126, or the number size #30 .1285

and so on


you can only cut maybe 1/32 of an inch that way, so a tapered reamer to go up some sizes, then one to get on size...
Click to expand...

bladsmth said:
Count,
He wants to enlarge the holes in pre-made blades to allow free passage of pins and rivet shafts. If you only reamed with an exact size reamer, you would need a full set to make the holes various sizes. The tapered reamers I use are just tapered milling tools that will open up a hole in a heartbeat. If you don't clamp the work firmly,and run them fast enough.... they will break in a heartbeat,too.
I always recommend that the tang hole be 150% the rivet size. On a 1/8" pin the .180" tang hole will allow a tad less than .030" clearance all around. If you get the size too close, any mis-alignment will make things bind up.
Click to expand...

I get what you mean.
I suppose I didn't explain it well.

I agree that you can use the tapered reamer to fit into a small tight hole and open it up.
A carbide countersink would also work the same way.
Just using an only slightly larger drill is too easy to catch, helicopter and break a drill.

I also know that you like to go with a fairly sloppy pin fit in the tang.
I like to go with a fairly close fit to keep things aligned so they don't slip during gluing and clamping.
that way I know after glue it will be as pretty much like it did when i dry fitted it.


If it's already heat treated, then he won't have to worry about the HT making his holes shrink

The rule of thumb I use on reaming is drill 1/32 smaller than the finished reamed hole
that's probably too much of a difference on a hole that small.

so a 3mm hole is about .118"
on a 1/8" hole .010 to .1285


I expect once he finds a size he likes he would just stick with it.
one tapered reamer and one at the end size.

I agree with your tapered carbide reamer to open it up.
I guessed that he would just use one to stop at whatever size he wanted.

I wanted to make it clear that a hole drilled on the size of the pin will not pass a pin as a slip fit.

I guess that's just the way I was thinking.
 
Last edited:
Internet has been down all week so thgis is first chance to read posts.

Thanks to everone who gave me suggestions as all make perfect sense and proves once again that there is more than 1 waqy to skin a cat ( figuratively speaking) and its great to find that folks are willing to give good - solid advise to one who is just starting to learn to walk. THANKS

Here in San Antonio i was only able to find 1 tool / metal place that actually carries any solid carbide bits. Odd that for a city of this size something that i would have assumed to be less scarce is as hard to find ( locally) as the chubacabra.
 
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