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SC2 mini lathe pops RCD when turned on? Willis Farmers Engine in 2″ scale Buying a quick change tool post – Which one? JPEG Slide Show Stuart Dynamo A Huge Thank You from the Melbourne Society of Model and Experimental Engineers! Chinese Mini-Lathes/Mills – DC Motor Controllers DTI Glass Boxford Replacement bearings Lathe headstock bearing access

Search for: Home › Forums › Materials › Topics Viewing 25 topics - 1 through 25 (of 25 total) Topic Voices Posts Last Post SC2 mini lathe pops RCD when turned on? 1 2 Started by: andy198712 in: General Questions 8 38 10 October 2024 at 15:58 andy198712 Willis Farmers Engine in 2″ scale Started by: Luker in: Work In Progress and completed items 5 7 10 October 2024 at 15:54 Luker Buying a quick change tool post – Which one? Started by: Volans in: Workshop Tools and Tooling 2 2 10 October 2024 at 15:48 Clive Foster JPEG Slide Show Started by: Vic in: The Tea Room 3 3 10 October 2024 at 15:45 SillyOldDuffer Stuart Dynamo 1 2 3 Started by: Steve Rowbotham in: Beginners questions 13 69 10 October 2024 at 15:39 Robert Atkinson 2 A Huge Thank You from the Melbourne Society of Model and Experimental Engineers! Started by: dhendley in: Model Engineer. 1 1 10 October 2024 at 15:25 dhendley Chinese Mini-Lathes/Mills – DC Motor Controllers Started by: Andre ROUSSEAU in: Help and Assistance! (Offered or Wanted) 6 10 10 October 2024 at 14:47 Robert Atkinson 2 DTI Glass Started by: Chris Crew in: General Questions 2 2 10 October 2024 at 13:53 AStroud Boxford Replacement bearings Started by: Bernard Reilly in: Help and Assistance! (Offered or Wanted) 1 1 10 October 2024 at 13:37 Bernard Reilly Lathe headstock bearing access Started by: Mike Hurley in: Manual machine tools 8 12 10 October 2024 at 12:40 mgnbuk Hot rolled angle problems Started by: Mick Bailey in: Materials 7 22 10 October 2024 at 12:22 Hopper New guy from Norway, planning a Bonelle grinder 1 2 Started by: Fulmen in: Introduce Yourself – New members start here! 17 38 10 October 2024 at 10:50 John Hinkley Sizing of 1/4” hex shanks Started by: Bill Phinn in: Workshop Tools and Tooling 14 22 10 October 2024 at 06:57 JasonB What did you do Today 2024 1 2 … 16 17 Started by: JasonB in: The Tea Room 62 401 9 October 2024 at 22:40 Nigel Graham 2 My very own Quick Change toolpost 1 2 Started by: Iain Downs in: Workshop Tools and Tooling 15 30 9 October 2024 at 22:07 Huub Thiel Nassovia vertical metal saw Started by: Sonic Escape in: General Questions 8 23 9 October 2024 at 12:18 not done it yet About cheap grinders 1 2 Started by: Sonic Escape in: Workshop Tools and Tooling 18 33 9 October 2024 at 12:03 Tony Pratt 1 Racing Motor Cycle Adhesion 1 2 Started by: Peter Cook 6 in: The Tea Room 18 35 9 October 2024 at 11:27 Hopper Bed for 6040 CNC? 1 2 3 4 Started by: Steve355 in: CNC machines, Home builds, Conversions, ELS, automation, software, etc tools 12 90 9 October 2024 at 10:20 Steve355 Deleted messages Started by: jimmy b in: New Forum Software questions, comments and Test Threads 1 1 9 October 2024 at 08:49 jimmy b Chester Super Lux advice 1 2 … 5 6 Started by: Taf_Pembs in: Manual machine tools 18 134 9 October 2024 at 05:22 Michael Gilligan Weather Started by: Michael Gilligan in: The Tea Room 1 1 9 October 2024 at 05:11 Michael Gilligan Arnfield Gravity Escapement Started by: Michael Gilligan in: Clocks and Scientific Instruments 6 21 8 October 2024 at 22:29 Michael Gilligan Tich Loco. A sad tale. Can anyone help? 1 2 Started by: simon1479 in: Introduce Yourself – New members start here! 10 29 8 October 2024 at 22:23 duncan webster 1 Making a tool holder for lathe inserts Started by: Steviegtr in: Workshop Tools and Tooling 9 17 8 October 2024 at 17:06 old mart   Viewing 25 topics - 1 through 25 (of 25 total)

Home › Forums › Materials › Notes on CNC Milling of 316 Stainless Steel This topic has 9 replies, 7 voices, and was last updated 16 February 2011 at 11:27 by Anonymous. Viewing 10 posts - 1 through 10 (of 10 total) Author Posts 14 February 2011 at 22:02 #29430 Anonymous Advert 14 February 2011 at 22:02 #64113 Anonymous I’ve recently had the need to make some parts on my CNC mill from 316 stainless steel. This has been rather a steep learning curve, so I thought I’d write a few notes on what I have learnt; the hard way of course.   The parts concerned are from 1.5mm 316 stainless steel sheet, and have complex outlines and internal cutouts. I had three off, of two parts, to make, and didn’t fancy doing it on a manual mill. The S/S used is 316 because, after machining and bending, the parts need welding.   I have turned a fair amount of 303 and 316 stainless steel with few problems and have always got an excellent finish using carbide insert tooling. I have done very little milling of stainless steel and no CNC milling of it, until now.   I used two cutters; a 6mm three flute centre cutting uncoated endmill, and a 2mm four flute centre cutting TiALN coated endmill, both from Garr Tool.   Looking up Machinery’s Handbook gave a surface speed of 200fpm for carbide in 316. Being cautious, so I thought, I downgraded that to 120fpm, corresponding to 2000rpm for the 6mm cutter. Choosing a chipload per tooth of 0.05mm gave a feedrate of 300mm/min. After a couple of broken cutters and another one worn out, I did what I should have done in the first place; put the kettle on and then look up the Garr Tool machining data. For 316 they give 20-35m/min and a feedrate of 0.01-0.025mm/tooth for a 6mm cutter. I chose 22.6m/min (1200rpm) and a chipload 0.025mm/tooth for a feedrate of 90mm/min. What a difference! The cutter ploughed through the cuts slowly but smoothly; yippee!   Figures for the 2mm cutter were 3500rpm and 70mm/min feedrate. That seems a very high rpm, but the diameter is three times smaller, so for the same surface speed the rpm needs to be three times higher. The feedrate equates to a chipload 0.005mm/tooth, at the lower end of the manufacturers recommendations.   I have added a few pictures in an album showing the parts and few snapshots of the machining in progress.   A few other random snippets. I used flood coolant at all times, mainly to flush away the swarf. The depth of cut with the 6mm cutter was 1.7mm, to ensure complete break through. With the 2mm cutter the same total depth was achieved in four passes, each of 0.45mm. Typically, despite breaking several 6mm cutters, I didn’t break a single 2mm one. The aluminium subplate is sacrificial. Better to cut into it than the table! Once it gets too badly mangled I’ll either recycle it or give it a facing cut. It’s scrap anyway; it was cut from a larger sheet that, due to a brain fart on my part, was ordered to the wrong size for a previous project. In retrospect I am amazed that the 6mm cutter actually worked with the original speeds and feeds; it just wasn’t sustainable for even one part. The local professional tool shop sold me some 6mm cutters with a small radius (0.3mm) on the tips as specially for stainless steel. I haven’t tried them, but can see that it makes sense, as the cutters wear initially on the sharp tips; if you don’t break them first of course!   One other thing, I also mangled a HSS drill on the manual mill too, by hesitating, and then getting it red hot trying to finish the hole. It was a vivid way to relearn the lesson of never, ever let the tool dwell when machining stainless steel. It’ll work harden before you know it. Then only carbide will touch it, if you’re lucky.   I hope this is of use to somebody, if only to prevent wallet damage. Mind is still sulking.   Regards,   Andrew   PS: Sorry about the mixed units, that’s just the way it goes, and I’m comfortable speaking both imperial and metric so it doesn’t bother me. Edited By Andrew Johnston on 14/02/2011 22:04:37 14 February 2011 at 23:54 #64117 SpurryParticipant @spurry Andrew   Are your coated toolbits HSS or solid carbide?   Whenever I have tried to machine at recommended feeds and speeds, the toolbits end up broken, so I’m not the only one to suffer.   Take care of the wallet.   Pete 15 February 2011 at 01:31 #64118 John Stevenson 1Participant @johnstevenson1 I am working with a company at the moment that is developing a hand held machinists calculator and believe me the speeds and feeds saga is exactly that. Plenty of tables out there but no one mentions a variable that takes into account the machine.   Many of the commercial cutter manufacturers assume every one has the all singing, all dancing latest Mori Seki with 5 axis as a 30,000 rpm refrigerated spindle and quotes insane speeds and feeds.   John S. 15 February 2011 at 08:02 #64120 adyParticipant @ady Did you ever try low speed high torque?   You get none of the heat issues, tooling has to be tip top and the machine needs good stiffness to compensate.   I’ve used this approach on both alu and stainless, but only as a hobbyist dood, high speed can be too nerve racking and prone to error issues. 15 February 2011 at 09:48 #64124 David ColwillParticipant @davidcolwill19261 I have some of Cutwels alpha mills and never had satisfactory results with them. I had a job to do on my cnc and decided to work out the speeds and feeds properly. I used the kennametal calculators:- http://www.kennametal.com/calculator/end_milling.jhtml All of a sudden my previously useless cutters performed brilliantly. The moral of this particular thread must be:- If in doubt sacrifice a goat before you start! 15 February 2011 at 09:52 #64125 PekkaNFParticipant @pekkanf Hello,   What mill did you use? Is it for hobby use or the to bring the bead on the table?   “I used two cutters; a 6mm three flute centre cutting uncoated endmill, and a 2mm four flute centre cutting TiALN coated endmill, both from Garr Tool.