Very stuck set screw 3/32

Athanasius said:
Summary: Very new machinist student gets 3/32 set screw very stuck in apparently poorly tapped hole in R8 fly cutter project.





My father-in-law and I tried the steps for an EASY OUT, but I warned him that set screws were grade 8 hardware. Obviously run of the mill drilling didn't work.


Thank you for your consideration
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Grade 8 fasteners are not very hard, around 40 RC I believe, you should have no problem drilling such a screw with a HSS drill of decent hardness.
 
It doesn't look like there is enough room to get a wrench on a nut even if you weld one on. I would first try drilling to the minor diameter and pick out what is left then run a tap thru. If that doesn't work then drill for a helicoil and install.
 
the trick here is to get a better weld job on the what is left of the old stud. get a heavy washer that just fits over the stud . weld it to said stud. you get more weld this way to the stud. when you weld nut to stud you are welding down thru the nut to the stud just the top of stud get welded to nut. get a good weld on this part of the . then weld your nut to the washer.weld all the way around. and the heat mite help jar it loose and bingo job done gotogojo
 
I would replace all the set screws with SHCS as long as the head fits in the counterbore. They are less likely to strip out.
 
Set screws are harder than grade 8. They won't drill with HSS bits. You most likely need a cobalt bit to drill it. I would drill it out to the thread minor diameter and re-tap the hole. I have had good success doing that.
 
If you dont have a cobalt bit, ive had luck with small screws and broken tap removal using a dremel with an inexpesive diamond bit set you can get at harbor freight. really does not take that long.as long as you can find one smaller than the tap drill size. good luck
 
rusty reamer said:
If you dont have a cobalt bit, ive had luck with small screws and broken tap removal using a dremel with an inexpesive diamond bit set you can get at harbor freight. really does not take that long.as long as you can find one smaller than the tap drill size. good luck
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Hint if you are using the diamond tools is to keep the cutting area flooded with water or oil. The grit on the tool will last much longer.
 
mark_f said:
Set screws are harder than grade 8. They won't drill with HSS bits. You most likely need a cobalt bit to drill it. I would drill it out to the thread minor diameter and re-tap the hole. I have had good success doing that.
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A "cobalt" tool is HSS .
 
What size is the set screw? 3/32 doesn't sound right.

Is it pre hardened 4140 or did you have it hardened after machining?
 
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