Viktor:
I didn't see your last question to this forum until today. I know how interested you are in all aspects of gundrilling, so I'll try to answer but it has been a while.
The coolant pressure was high as it would be on any gundrill, I suppose. Probably over 1000 PSI. I suspect that he used...
To start, we went with the manufacturer's recommendation times three.
We use a generic gundrill oil and drilled a few holes on our Mollart which would drill the job if it comes to pass.
The .312 diameter drill was from Eldorado. Standard carbide. At 1/8 feed with a 30-20 grind, about 2.5"...
The test drilling was worthwhile; we learned enough to know we can drill the holes. Having experienced operators certainly pays off!
Thanks again for the thoughts; I won't hesitate to bring other questions to this forum.
I now have a sample piece of HARDOX to try. Since we're a job shop, we try 'most anything!
Viktor - I suspect you already know the answer to your question about what grade of carbide we use. Since we're jobbing as gundrillers, we rarely have the luxury of buying drills with non-standard carbides...
I just got an RFQ for gundrilling a .312 diameter hole in material called "Hardox" (by Oxelosund) which will be at 50 Rockwell. Their website is not helpful about this process. Any suggestions about quoting (or not)and drilling (or not) will be appreciated. There wil be only six pieces...
BertusP:
Danjon Mfg. Corp. in Cheshire, CT not only makes the tooling, but can provide detailed instructions/suggestions
[to their customers, I presume] for this sometimes tricky operation. I don't know if they have an email address, but
you can ask for Mr. Metz at (203)272-7258.
