Thanks; More Detail (CAUTION-long-winded)
Thanks everyone for your time and input, I appreciate it.
Ok, here's the saga (CAUTION-a bit long-winded):
The project required this #55 drill to do a step in a dental lab process. The labs all use 2.35 mm collet rotary handpieces (and don't ask them to use anything else...). Those handpieces will not accept anything over 0.095 (3/32+), they will accept a considerable tolerance under 2.35 mm.
So, since we were just doing small quantities for development, we cut ferrules from 3/32 hypo tubing (turns out the ID was just right). Glued the ferrules with 7649 primer and 609 retaining compound (don't believe the literature that you don't REQUIRE primer for ss/hss). Dispensed these with small droppers with syringe needles. The drill bits are standard Viking HSS bright-finish. We started needing a lot of these (250/month), and the cutting/gluing is a PITA. Can get ferrules made, but the gluing is still a PITA.
I had started looking for someone to make custom a custom drill (again decent quantities 250-400/mo) for over a year and have been mostly unsuccessfully; I've contacted and sent drawings to around 15 companies.
Have not found anything off the shelf in HSS/cobalt/stainless, with the right diameter, and that has the required flute length of ~0.7" min, and 2.35 mm shank. Carbide is too brittle.
Went to the small adapter shown below (has an advantage that it can be re-used also with any #55 bit), which we are getting made. This adapter has a tight concentiricty spec and the bore is at the tolerance limit for the stock drills. With this relatively short adapter, the setscrew flexes the bit (even with moderate pressure), and even though the tolerance is tight, the distance between the screw and nose is so short that it often creates excessive additional runout at the end of the drill. I do have a longer design of that adapter, but it's sort of defeating the purpose with regard to runout and compactness, and we eventually need someone to just make integral 2.35 mm shank drills anyhow.
So, we are back to gluing the drills in those adapters while still looking for a vendor to make stinking simple HSS bits with a 2.35mm shank. So, I was inquiring if perhaps there might be a collet gizmo somewhere (I knew the chances were slim).
Thanks so much for everyone's input, if anyone knows of some sources for custom drills (hss, or stainless), drop me a PM, the quantities are probably 250-400/mo, and we also have another larger drill (3/32) with a pilot point (been grinding those from a stock Viking 3/32 on a TC grinder in the shop). We are not nickel-and-diming these drills, but the price should be reasonable,and good quality (similar to an off-the-shelf Viking drill).
This is another example of how "simple" things in a project can be a real PITA, never thought it would be a major operation to find vendors to make a simple HSS bit.
Thanks again for everyone's time.
