Lee Jones 6 | 19/05/2020 13:56:09 |
258 forum posts 125 photos | The current set-up is currently limited to ~1mm DOC before things get too loud and shaky. However, I'm planning to rectify that shortly: Stabilising a Milling Machine How hard should it be possible to push such a machine during various types of operations? |
JasonB | 19/05/2020 13:58:01 |
![]() 25215 forum posts 3105 photos 1 articles | DOC in what? How wide a cutter 3mm or 80mm facemill HSS or carbide? Cheap cutters or decent? |
Lee Jones 6 | 19/05/2020 14:10:59 |
258 forum posts 125 photos | In steel, with both 50mm carbide facemill and 10mm HSS endmill. CHEAP! :D |
Lee Jones 6 | 19/05/2020 14:12:16 |
258 forum posts 125 photos | Posted by Lee Jones 6 on 19/05/2020 14:10:59:
In steel, with both 50mm carbide facemill and 10mm HSS endmill. CHEAP! :D Chinese facemill/inserts. |
Dave Halford | 19/05/2020 14:13:46 |
2536 forum posts 24 photos | Saw your other post Lee. What do the inserts look like? Have you checked the holder for runout? Some ER's are a bit grim. It sounds like something is slack enough to go knock, knock when you pull on it. The head should not shake independently from the column. My Centec 2A sits on a wheeled tool trolley and stays put so should yours. Edited By Dave Halford on 19/05/2020 14:17:36 |
JasonB | 19/05/2020 14:25:21 |
![]() 25215 forum posts 3105 photos 1 articles | Go search the forum for facemill, I posted how bad a cheap 50mm facemill was, the reasons why and how I cured it. Also look at StevieGTR's recent threads where with the right inserts his facemills worked well, the cheap 50mm one did not but all in the same machine Get some half decent milling cutters to, could do worse than these
Edited By JasonB on 19/05/2020 14:27:39 |
Martin Connelly | 19/05/2020 16:33:19 |
![]() 2549 forum posts 235 photos | What is you definition of push? You can't just crank the handles as fast as possible and rev the tool as fast as possible. Martin C |
HOWARDT | 19/05/2020 16:43:27 |
1081 forum posts 39 photos | I have a SX2P with 3MT spindle and the original ball bearings about three and half years old. Running a 3MT 25mm diameter 2 tooth insert cutter with TPUN inserts at full speed, 2500 rpm, I can getaway with 2mm depth of cut on pretty much a near full width cut. Ways have to nipped up a bit otherwise the clatter becomes a bit much. It does cover the machine and bench in hot chips very quickly. |
Lee Jones 6 | 19/05/2020 17:00:36 |
258 forum posts 125 photos | This is what the inserts look like: Not checked it for run-out, but the loud noise and vibrating happens with different cutters. [Although, it has also just transpired that I have not been using my collet chuck properly!] I'll do that Jason, thanks. By push it, I purely mean DOC. I don't have 2500RPM to play with. My machine tops out at 1600RPM.
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Lee Jones 6 | 19/05/2020 17:02:32 |
258 forum posts 125 photos | Posted by JasonB on 19/05/2020 14:25:21:
Get some half decent milling cutters to, could do worse than these I just bought one of their roughers - arrived today. Might give it a spin tonight (with my newly de-burred collet set!) and report back. |
JasonB | 19/05/2020 17:10:27 |
![]() 25215 forum posts 3105 photos 1 articles | So here is the thread with my posts about one of the very cheap facemills and very cheap inserts. Starts off with the vibration you mention shown by the light moving about, later posts shows head is a loose fit on arbor and later still what a difference better quality inserts make. That was a couple of years ago, since then I have tried out the reasonably priced facemills and inserts from ARC, if you can get your hear running true then their inserts would be worth fitting. With those things sorted I would say a good starting point would be 1mm DOC over 80% of it's width so 40mm wide passes at 750rpm in steel and 2000rpm on aluminium. Stevie's finding with a similar very cheap one, other cutters work well with decent inserts Edited By JasonB on 19/05/2020 17:29:30 |
Ron Laden | 19/05/2020 17:48:12 |
![]() 2320 forum posts 452 photos | Posted by HOWARDT on 19/05/2020 16:43:27:
I have a SX2P with 3MT spindle and the original ball bearings about three and half years old. Running a 3MT 25mm diameter 2 tooth insert cutter with TPUN inserts at full speed, 2500 rpm, I can getaway with 2mm depth of cut on pretty much a near full width cut. Ways have to nipped up a bit otherwise the clatter becomes a bit much. It does cover the machine and bench in hot chips very quickly. Thats a bit more adventurous than me Howard on my SX2P I run the 25mm 2 insert cutter at 1500 rpm with an APMT insert with a max cut of 0.5 mm on steel and 2500 rpm on alu with the APKT inserts max cut 1,5 mm but more often at 1.0 mm. I do adjust those settings to suit the width of cut but I am not brave enough to even consider 2.0 mm cuts in steel. If you are getting away with it and the machine is happy then thats fine but I dont think my SX2 would be happy with it or at least I wouldnt expect it to be. Edited By Ron Laden on 19/05/2020 17:52:45 |
Martin Connelly | 19/05/2020 18:37:12 |
![]() 2549 forum posts 235 photos | A good starting speed and feed for the 50mm 4 insert cutter on steel is 450rpm and 225mm/minute. A good starting point fort the 10mm HSS cutter is 800 rpm and 100 mm/min per flute, for a 4 flute that is 400mm/min, for a 3 flute 300mm/min. Faster feed rates will cause a lot of vibration and noise. Slower feed rates will cause rubbing not cutting which also causes vibration and noise. Do you have power feed or are you turning handles? Martin C Just spotted your other thread regarding stabilising the machine and I see it has a power feed unit. I would suggest finding out what the feed rate is for each setting of the speed control knob on the power feed and create a table to set it to known feed rates. That way you are also able to repeat setups that you know work or avoid ones that don't. Edited By Martin Connelly on 19/05/2020 18:42:47 |
Clive Foster | 19/05/2020 19:13:01 |
3630 forum posts 128 photos | If my morphologically similar VFD controlled Chester machine (not the usual Lux) is anything to go by what you have is, for all practical purposes, a benchtop Bridgeport. When it comes to cuts rather than work envelope of course. Standing out in the open like that the practical limits are more to do with hot, or even cool, metal shower than fully exploiting the machine capabilities. When I got mine I already had a couple of the old style cardboard slide'n cutout window calculators that the cutter makers used to issue for, mostly, publicity purposes. I knocked about 1/3 rd off the figures for comfort and called it good. Since moving to a Bridgeport I've seen no reason to change the approach. Mit and flood coolant on board means I could easily but, frankly, the extra mess is rarely worth it. Do remember that, despite its impressive to ME eyes size and weight a Bridgeport is, in industrial machine tool terms, very much the 9 stone wimp wot gets sand kicked all over him. So taking around 2/3rd of this table values might be a reasonable starting point.
But I find it much easier just to tweak what Mr Osbournes slide rule says. Somewhere on t'net there are some nice simple graphs of speed, feed and cutter sizes. I have one for lathe working laminated and pinned to the wall. Clive |
Ian McVickers | 19/05/2020 20:05:53 |
261 forum posts 117 photos | I think your asking a lot of the machine if you want to push it more than 1mm DOC in steel. I had the GH universal and ended up stripping down the headstock and quill and fitting decent bearings to make it quieter. It used to rattle like hell before I did the refurb. Had to use bearing fit on some of the bearings because the recesses were oversize which really doesnt help. Refilled with H32 oil and it definitely improved things. Mine was sat on vibration feet and didnt jump about but was noisy. |
old mart | 19/05/2020 20:31:59 |
4655 forum posts 304 photos | I'm also of the opinion that if you want to cut a lot of metal, get something with some power. |
JasonB | 19/05/2020 20:39:27 |
![]() 25215 forum posts 3105 photos 1 articles | From what has transpired in lee's other posts I think his best option would be to reassess the vibration and inability to cut more than 1mm after a half decent milling cutter has been correctly held in a collet and again some half decent inserts fitted into a true running cheap facemill. |
HOWARDT | 19/05/2020 20:51:10 |
1081 forum posts 39 photos | Remember those roughing cutters are HSS not carbide. I have them in 8 to 16mm, most awaiting a regrind. They shift metal but need to be kept cool and lubricated. |
Lee Jones 6 | 19/05/2020 21:49:31 |
258 forum posts 125 photos | Spent some time on the mill this evening. Firstly, I've put it on some interlocking foam matting, which has helped a lot. However the over-all noise reduction has highlighted what I think might be a bigger problem. Have a listen to the video below. The knocking coming from the gearbox is quite disconcerting. Edited By Lee Jones 6 on 19/05/2020 21:50:20 |
Martin Connelly | 19/05/2020 22:00:54 |
![]() 2549 forum posts 235 photos | You have your 50mm cutter on H1 which is 600 rpm. This is about 1.5 times as fast as I would be running it. Try the next lower speed. Your workpiece looks to be about 150mm wide. At 600rpm and going at the feed it looks like you have (about 150mm/min) you are probably alternating between cutting and rubbing. The burr being pushed ahead of the tool also looks like a lot of rubbing and not cutting is taking place. The same feed with 280rpm should cut on each tooth for the whole cut. Martin C Edited By Martin Connelly on 19/05/2020 22:03:39 Edited By Martin Connelly on 19/05/2020 22:14:31 |
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