Punch Hardness

[Sliver Shooter]

I have a heck of a time threading Drill rod so the threads are straight with the world. It don't help matters that my left arm is semi worthless for 6 months. Can a guy harden a Grade 8 bolt once its machined for a punch or is it not able to temper?:veryconfu

[chuckbuster]

Grade 8 Bolts are "Medium Carbon Alloy", should be hardened through in the mid to high 30's on Rockwell "C" scale. Not really "Hard" actually but a good TOUGH range appropriate for a bolt. Since they are a Carbon Alloy should be heat treatable with minimal issues after machining at least for some one that understands Heat Treating, I have a friend that takes care of that for me, he does it for a living, has taught me enough to be dangerous but not competition :)

Not sure exactly what you need in a punch but if you want PM me and I can get pretty much anything you need made, heat treated and ready to use.
Kevin

[aaronraad]

I'm specing out my punch hardness at 57-60 HRC. This should keep it just below the die hardness.

[midnight]

I have made a number of core seat punches useing ½in grade 8 bolts and didn't harden them at all. I have only used themto seat a couple dozen 375 cores and they worked fine but I don't know how they will hold up. I can case harden them here at home but have not done it yet. That wouldn't make them any stronger but they would be wear reistant. If the case is harder than the die, the die might be damaged. I had to make my own punch holders too becaues of the coarse thread of the bolt. Now that I am setting up a milling machine I will make them from W 1 drill rod and drill and tap the end to fit the RCE punch holder. If you use a variety of jackets, you can never have enough core seat punches.

Bob

[aaronraad]

Theoretically I would have thought you can go as hard as you like for a core seating punch, given the jacket is between the punch and the wall?

My 57 to 60 HRC spec is for my boat tail punch going into my point form die.

[Sliver Shooter]

I just have a time threading the 1/2" drill rod to make the derim punches. SOFMatchstaff made me a shaft for my pneumatic cylinder and it's set to use a 1/2" threaded punch. I haven't mastered threading on my minilathe and use a die to attempt threading drill rod. Drill rod tempers up perfectly for the job. I wasn't sure if grade 8 bolts could be hardened so there is no bending with use.