I have uploaded a small 19KB .GIF file to rapidshare showing a drawing of a simple adjustable spring anchor I am making from a 10-32 screw. Here is the download link...
Regarding the drawing, an extension spring hook goes through the .098" hole, and the other end of the screw gets a hex nut that can be no larger than 5/16" flat to flat, such as part # 90760A411 from www.mcmaster.com. Due to space limitations, the hex nut must be adjusted with a box end wrench.
The .359" to .390" OD spring ( similar to the #80583 www.centuryspring.com) uses .08" diameter wire, but the problem I ran into is that the hole is not really large enough for the spring, due to the curvature of the hook.
Can a machinist cost effectively just make a .098" wide slot in the screw, about .145" to .155" long, instead of a .098" hole?
I know slots are generally easy to do, but since it is so small, I wanted to get some feedback. If the slot can be made cost effectively, It will work well with the spring.
If the slot cannot be made cost effectively, then I must use a larger screw that will allow for a hole of about .145" OD. A 1/4-20 or 1/4-28 screw would work great, but I could not find a nut that is 5/16" flat to flat max, and that has a 1/4-20 or 1/4-28 thread.
I did find a 1/4-32 nut (part # 91862A516) from www.mcmaster.com, which is only 5/16" flat to flat, but then I can't seem to find a screw for it. Mcmaster also sells a 1/4-40 nut that would work, but same problem, I cannot find a screw.
I would appreciate any feedback anyone can provide. Hopefully, just creating a slot in the 10-32 screw is viable and cost effective.
Thanks for your help.