Tapping 304 Stainless, 5/8 - 11 x 1.25 deep, blind hole. Need to do 120 holes - any clues???
Tapping 304 Stainless, 5/8 - 11 x 1.25 deep, blind hole. Need to do 120 holes - any clues???
i have a few, dont know if its what your looking for tho......
on stainless, i like to drill the hole about 3-5 thou (.003-.005) oversized of what the chart says, have atleast a .03 chamfer before tapping. i like to use OSG elektraLUBE coated taps, and I use anchorlube on the holes for extra lubricity if needed. Anchorlube is a green paste and helps out tremendously. If your having chip build-up in the hole, you might have to run more depth passes like a peck cycle. I havent had the best of luck using spiral points for chip evacuation on stainless, and i hate it when i dont have much wall thickness around the tapped hole (example, 5/16-24 tapped hole in 7/16 diameter round stock).
you could also try thread milling i suppose....
I've had better luck with blind holes where you are limited to hole depth by going in after and hand tapping the hole with a "Bottom Tap". I know it will take a lot of time but is better than breaking taps. I've also used a mixture of cutting oil and Molly D.
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Thread mill them. One tool should last 120 holes. Wayyyyyy better than tapping.
Almost done with the job, I actually drilled 1/64 oversize hole, power tapped about .8" deep, then finished by hand with taper, plug, finally bottoming taps to depth. Molly dee cutting fluid. i have 24 holes still to do - haven't busted a tap yet (knock on wood ).
Just how I would have done it......Glad to hear it's working for ya.
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OSG VA3 Taps are specifically designed for stainless. I would of pecked tap all the way to the bottom with no need for the hand work. Otherwise thread milling would of been your best bet. Work smarter, not harder.
Finished. No busted taps. Thread milling not an option for me - manual equipment only. And "thanks" for the "work smarter, not harder" comment, that really gave me a boost - NOT!
I usually custom make prototype or small qty. runs. Took this job 'cos things were a bit slow at the time. Thanks for all replies.
Good Job !
A lot of people responding to these posts assume many things depending or their set-up not yours. So unless "all information" is provided you will get posts that do not relate to your particular set-up. But it is nice though that people do respond and try to help where they can. Free information and help is hard to come by when everybody wants $$ to share their ideas and or knowledge. These forums, albeit, a good source for info and help, take everything with a grain of salt and weed out the junk that doesn't apply.
We all live in Tents! Some live in content others live in discontent.
good job. sorry about the thread mill advice. you probably wouldnt have had that advice if we knew you were on a manual remember, better descriptions lead to better advise. but anyways, you should really look into the OSG elektralube taps if your going to continue to do stainless. 95% of our workload is stainless and its been a valuable lesson learned about using the right tooling for stainless.
I'm new in here, next time will provide more info. I wound up starting the hole (under power) with an Accupro three flute, spiral point tap. I only got one and it lasted thru' the whole job, although it was really "working" towards the end.
thats koo. if your going to continue to do stainless tapping in the future, i highly suggest the osg elektralube taps. i have tried alot of different fluids and taps, and if you have to tap, i reccommend them. thread milling is still somewhat new to me but it works great if you have the machine capable of doing it.