Drilling and tapping questions

L

lesoleilnoir

Joined
Jun 15, 2001
Messages
149
Alright,

So I working on my first knife. It's a boot knife and kinda tactical looking, so I'm going to use exposed caphead screws to fasten the scales. The blade is 3/16 440c

I was planning on using 6-32 screws does that sound reasonable? What size hole do I need to drill. I assume I need to tap before HT, correct? Do I need to use an oversize tap, or the exact size.

Also, I was going to tap straight through and just reverse-thread the screws on the flip side? Is this stupid?

Feelin' kinda lost here, so I any help is appreciated.

Thanks guys,
Dan
 
Thanks Mike, that does help.

I'm still wondering about the tap needing to be oversized or not. The steel will change dimension ever so slightly during HT won't it?

Anyone?
 
The steel will be dimensionally altered slightly during heat treating and tempering. If you have an OLD tap to just run through the threads that would suffice to clean them up somewhat. Be sure to use some cutting fluid or oil to keep it from sticking. If you have used foil to treat the blade, there should be little or no scale to worry about. Basically, I suggest trying it on a piece of scrap so you get a feel for it.

On threading: Get yourself a machinists handbook. There are tons of stuff in there, but most importantly you will find tables which give the percentage of usuable thread from tapping with certain diameter starting holes. Most of the time, 75% is about all you can expect to get from a tapped hole. Any grain growth will only squeeze up your hole (keep yer minds outta the gutter, boys) and make the threads fit tighter around the fastener.

Good luck, and tell us how it came out!

Jeff
 
There are varying degrees of clearance for a given tap size, I believe it is the H number. If you heat treat the blade only, I don't think you will need taps with greater clearance. Tapping straight through won't require reverse threaded bolts one side (if I understand what you are asking), it's no different than a nut threading on in either direction.
 
Dan, If you want to screw the scales into threads in the tang you will need to drill and tap a hole for each screw. If you have time you can bring your knife over and we can work something out with it. We could make speacial fasteners to fit your knife. I am between jobs again so I have some free time durning the week.

The NVKC is meeting Thursday night 8pm. This will be a social meeting so bring knives. Dan you welcome to come to the meeting. Bring your knife project and we can talk about it at the meeting.
 
the easiest thing to do is drill a .188" hole and stick a cylinder in the hole that has been drilled and tapped for whatever size screw you want to use, then drill the handle material the same size and countersink on top/cutting the cylinder to a size that is shorter than both handle thicknesses and blade thickness..............www.halperntitanium.com has pivot pins like this that are very cheap. This is the easiest way and will save you a lot of trouble.
 
Tom,

I'm not quite sure I'm following. Are you saying to use the pinstock as a type of spacer inside the tang as a barrier between the two screws?

Dan
 
Dan, NVKC meetings are at 8:00 pm, third thursday of each month at 105 N. Maple Avenue, Falls Church, VA.

If you want to come by I will show how to drill and tap the pins on the lathe for your knife handle.
 
Im sure Ray could help you with this...........but at halperntitanium.com they sell the following:

Stainless Steel Pivot Pins (Two Styles Available)<-these are just precision cut cylinders with holes tapped thru the centers.

1/8" x 1/2" x 2/56 ($2.00 ea)
3/16" x 1/2" x 4/40 ($1.00 ea.)<- I use two of these, thru two .188" holes in the handle material AND the the blade tang, with a .225" countersunk hole near the surface on both sides of the handle holes for the 4-40 screw heads...........I cant draw on here but it is the simplist way to attach a handle that I know of.
 
Tom,
That is just an excellent idea. It sure is a lot less fooling around. I never would have "thunk" it.

C Wilkins
 
electrical standoff's make it even easier, many sizes & thread choices, as well as materials, brass, stainless, etc. I use 1/4" long by 1/4" diameter, 4-40 threads, press fit into tempered tang, counterbore the inside of your handle slabs, approx. 1/16th" on a 1/8th" tang, as Mr Mayo suggested, you're home....I buy them here:

www.amatom.com

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