Tools, Sharpening and Power Machinery - RPM for drilling 304 stainless
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bigtonyicu
09-30-04, 07:21 AM
Hi I have to drill a 1 inch diameter hole 4 inch deep in 304 stainless, I'm working with a metal lathe and a 1 inch diameter Prentice Bit I 'm woundering what rpm I should be runing at, and what type of pressuer light medium heavy. and of course tuns of cutting oil
Shopman
10-01-04, 06:11 PM
Hi,
I have 26 years experience working in a machine shop with primarily stainless steel parts. 304 stainless is a gummy material, and a good cutting fluid or oil is very useful. Do not use a lubricating oil, as this will make things worse instead of better. 304 and 316, when using high speed steel tools, you need to run at around 40 to 50 surface feet per minute. At one inch diameter, using 45 sfm this would be 172 rpm. ( 45/ (dia. X .262) ). As for the feed to use, if cranking a tailstock I'd cram it for all it's worth. The correct feed, if you have a way of using the carriage to feed the drill in, is around .010" ipm. If you ran the speed any higher than recommended you'd run the chance of work hardening the material. 304 does not severley harden as some metals do though. Drilling as deep as you are you'll have to clear the drill often to keep cutting fluid at the tip. If your lathe has a coolant system flush as much coolant as you can, aimed right at the hole. For home use I recommend a synthetic coolant, since they can go a long time before before being overtaken by bacteria. Any questions regarding machining will gladly be answered. Andy
I just joined the forum today after finding an answer on google (from a post on this forum) to a compressor question. My extension cord was too long.
I have 26 years experience working in a machine shop with primarily stainless steel parts. 304 stainless is a gummy material, and a good cutting fluid or oil is very useful. Do not use a lubricating oil, as this will make things worse instead of better. 304 and 316, when using high speed steel tools, you need to run at around 40 to 50 surface feet per minute. At one inch diameter, using 45 sfm this would be 172 rpm. ( 45/ (dia. X .262) ). As for the feed to use, if cranking a tailstock I'd cram it for all it's worth. The correct feed, if you have a way of using the carriage to feed the drill in, is around .010" ipm. If you ran the speed any higher than recommended you'd run the chance of work hardening the material. 304 does not severley harden as some metals do though. Drilling as deep as you are you'll have to clear the drill often to keep cutting fluid at the tip. If your lathe has a coolant system flush as much coolant as you can, aimed right at the hole. For home use I recommend a synthetic coolant, since they can go a long time before before being overtaken by bacteria. Any questions regarding machining will gladly be answered. Andy
I just joined the forum today after finding an answer on google (from a post on this forum) to a compressor question. My extension cord was too long.
GregH
10-01-04, 08:28 PM
Andy,
Glad you found an answer to your problem and thanks for your expertise.
Glad you found an answer to your problem and thanks for your expertise.
bigtonyicu
10-07-04, 12:24 PM
the minimum speed on my lathe is 525 rpm that's going to be a problem
mmurray70
10-08-04, 08:16 AM
That will be to fast. It will probably work harden.
And i think shopman made a mistake with the feed. I'm not sure if hes suggesting 0.010" per flute or 0.010 per revoloution (0.005 per flute). But defenatly not 0.010 per minute.
If he meant 0.010 per fulte the feed would be 3.44 IPM at 172 RPM. Be sure to use a decent feed with stainless.
And i think shopman made a mistake with the feed. I'm not sure if hes suggesting 0.010" per flute or 0.010 per revoloution (0.005 per flute). But defenatly not 0.010 per minute.
If he meant 0.010 per fulte the feed would be 3.44 IPM at 172 RPM. Be sure to use a decent feed with stainless.
bigtonyicu
10-08-04, 03:21 PM
any idea suggestion on waht the best way to reduce the rpm on a taig lathe to those speed
marcusl
10-09-04, 12:14 PM
Your Taig micro-lathe is intended for small jobs. Drilling a 1" hole in stainless is a job for a full-sized shop lathe.
bigtonyicu
10-10-04, 07:29 PM
what about drilling a starter hole and expanding it with a boring bar?
mmurray70
10-12-04, 10:27 AM
That just sounds like a nightmare. I have a Taig lathe myself and they do come in handy but i wouldnt want to tackle a job like that on mine.
Forget about doing it with a 1" bit, just aint gonna happen.
A starter hole and boring it would be your only choice. And that aint going to be fun with a 4" depth. id say youll have to bore 2", flip it and bore the other 2".
I'd say your best bet is to head on over to http://groups.yahoo.com/group/taigtools/ . Post your question there and they should be able to help you. I dont really have much experiance in Stainless so its better to get another opinion.
Forget about doing it with a 1" bit, just aint gonna happen.
A starter hole and boring it would be your only choice. And that aint going to be fun with a 4" depth. id say youll have to bore 2", flip it and bore the other 2".
I'd say your best bet is to head on over to http://groups.yahoo.com/group/taigtools/ . Post your question there and they should be able to help you. I dont really have much experiance in Stainless so its better to get another opinion.