How To Cut Threads In SS Backspacer/Standoffs With 2-56 Tap

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bink

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I attempted the first one by hand trying to go slow and go clockwise until the pressure increased and then counter clockwise to clear the cutter and then clockwise again. I used cutting fluid, but the tap still broke in the SS standoff and I am sure I will not get the broken piece out. Need to purchase another 2-56 tap and I have three more standoffs left in an effort to get two good threaded ones. I can only damage one of them. What is the best method/process to thread SS standoffs and the best type of tap? I purchased the .140 sized standoffs (STDOFB) with an inside diameter drilled for threading 2-56 threads per the KnifeKits site. Please help with a detailed process of how it can be done with success. Thanks in advance.
 
Are you certain they are drilled correctly? If it were me I'd re-drill them just to be sure, they may be a bit under sized. If your keeping the tap at 90 deg angle, plenty of lube, and going slow, you shouldn't have much trouble. I'd be looking really close at the predrilled holes.
 
I am not sure what the best number drill or hole size is for cutting the threads in SS. On some charts I see #50, #49, #43, and #41. I do think that might be part or all of the issue though. Any guidance on which number drill size is best would be appreciated. Thanks.
 
In a vise with a wide rubber band around it to prevent damage. Are there better ways to hold it? I did my best to start it straight. What is the best process or method when doing it by hand? Thanks for your help.
 
I use a small machinist vise that has a vee in the jaws for holding round objects. I have a hand tapper ( a device for holding the tap,with a handle for turning it,) that I set on top of the vice. This starts the tap straight in the hole. I sometimes tap my standoffs while they are still in the collet of my lathe after drilling my holes,before cutting them off of my round stock.
 
Bink, I'm guessing your building a folder, and in my newb opinion, I don't think a 2-56 has to be able to really torque down that much on something. If you're tap just feels way too tight no matter you do, I'd go up a size on the drill bit. You have to have a nice set of bits though, not just fractional sizes. You need to have a complete number set, try drilling with the bit the tap chart calls for and then go to the next number bigger. The difference will seem insignificant and you'll almost think it didn't even remove any metal, but it can make all the difference for threading. And, again, how much torque do you really need? Your not going to strip the threads by only going up one number size drill bit, again, that's just my opinion.
 
The best I can tell it looks like I should drill it with a #49 drill based on the LittleMachineShop Tap & Clearance Drill Sizes chart I found. It says 50% thread for SS for a 2-56. If that seems too tight I will try the next larger sized numbered drill (#48). I have to order another tap before I can try it again unless I can find another one in my shop. I am trying to convert a Benchmade folder with a G10 backspacer to an open design with the round SS standoffs. Thanks for everyone's help and suggestions. Any additional info is welcome while I wait for more taps.
 
For most knifemakers, tapping standoffs is a difficult job, in fact I consider it so much of a pain in the rear that I buy nothing but standoffs that are already tapped.

Depending on the grade of stainless, you can save the part by putting it in ferric chloride overnight...that will usually dissolve the tap, or at least eat enough of it away that the rest can be blown out with an air hose. (This "trick" is especially handy for a broken tap in Ti).

Speaking of Ti, nearly all of the folder parts I use now-a-days are the Ti parts from Steve Kelly. (TiConnector.com). Theres nothing out there that even comes close to the tolerances Steve keeps on his parts, and for a lack of a better way to say it, your folders will just sorta "fall" together with his parts versus most others.
 
I don't consider myself a knifemaker yet (I would like to do that in the future), but trying to tap standoffs has been a pain. I think I tried this once before and gave up. I want to master it this time. The ferric chloride sounds like something neat to try. Looks like I can get that from Radio Shack if their stuff is concentrated enough to do the job. Thanks Ed.
 
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