DOC in what?

How wide a cutter 3mm or 80mm facemill

HSS or carbide?

Cheap cutters or decent?

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

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

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

I'm also of the opinion that if you want to cut a lot of metal, get something with some power.

**LINK**

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.

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

I have seen the whole video now and edited what I wrote.

Martin C

You need to cut not rub. I was judging the width of the material by the fact it looked about 3 times as wide as the cutter. A 4 insert carbide cutter at 50mm diameter being used on steel should be running at about 450 rpm for the correct surface speed on steel. Slower is better than faster so you need to run at 280 rpm. At this rpm to have each tooth cut 0.125mm per rev you need to travel (feed) at 140mm/minute. Carbide inserts can be quite blunt compared to HSS so not feeding fast enough causes the insert to slide over the surface rather than digging in and cutting. The curling burr on the top of the cut is evidence of a lot of rubbing rather than cutting.

Find the power feed setting that moves the table 140mm in 1 minute and use that with 280 rpm and see if it all works more like you expect. The suggestion of new inserts of known quality may help as well.

Martin C