2mm endmill help

Some feedback on the Usovo ER11 spindle conversion...

The owner has clocked sub 1 thou runout on the spindle itself and on a cutter in the collet. The bearings that came with it did not find favour due to noise and suspected play and were replaced with better off the peg sealed ball races.

Interesting upgrade

**LINK**

https://www.usovo.de/shop/advanced_search_result.php?MODsid=ff390ij4amcv6lfpo3468mjn21&keywords=tuning-spindle&x=0&y=0

MichaelG.

I've had a busy weekend in the workshop:

I didn't manage to run the CNC , but I did manage to re-spindle it:

Looks interesting. What is it?

Many years ago I needed to do some very small precision drilling, so I bought one of ARCs ER16 high speed spindles.

That project got done and as part of workshop tidy the spindle got packed away for “later”.

I don’t think they still sell them, but similar spindles can be found out of China.

it runs of an invertor, 750w and 4-24k rpm IIRC

Bit overkill for this mill I suspect, but already in the workshop and should solve the runout issue.

Seemed worth a try for the time investment

Dave

Thanks. I had a shufty on fleabay and found several variations. I suspect this option will only be attractive if you already have one of those kicking around.

My next step will be to try making a better fitting collet for the Proxxon spindle. It's not top of the 'to do' list though and I need to sort out a skinnier slitting saw before I can do it.

Good news!
My CNC failed to snap my last 2mm endmill last night
The Job started:

and then it progressed some

As it was all looking good I even went and sat in the garden with a beer, keeping an ear out for the noise.
I was back to watch the pocketing process, as the rest of the cuts were small width, and this was the full width, after all the other milling.

took just under 2h20.

End result of the roughing pass:

Somethings gone wrong here, the pocket is supposed to be a curve:

Turns out the recycled bearing on the X Axis has collapsed/ jammed.

Must have happened pretty much at the end, as the other shapes look OK.

That's why I took the stock off - cant run the finish on it until the leadscrew is sorted, which means stripping the table out...

Still, massive progress, and the new spindle seems to have made a difference.
I think its now in the 'tune' stage, rather than the throw things at it stage

Thankyou all

Dave

That looks a big improvement, did you have a similar amount of tool stick out or have some of the flute inside the collet?

It will be interesting to see how the raised features measure up once the final cut has been run.

I stuffed the endmill into the collet further - as I could do now its ER16. This spindle is loads quieter, both cutting and idling.

I'll run the job from scratch once the bearings are sorted, but I am also interested - that should allow me to tune which is where I started this whole thing.

Dave

6mm is a good size for solid carbide for a machine like that and can use the speed.

I also have an MF70 and decided to check the play and runnout. Measuring on the shank of a 3mm endmill I got a play of around 0.02mm and runout of around 0.04mm.

**LINK**

So far I have only broken one 1mm end mill when cutting a keyway in a silver steel shaft. This was mostly my fault. The first cut just put a flat on the shaft and the second cut was a full slot and was too much with the depth of cut I had chosen. Reducing the depth of cut resolved the problem.

Cheers Roger.

Sounds like you are doing better than Dave or myself, you have about half the runout that we have measured. I think I've broken three 1mm cutters, one of which was from a stupid mistake. Dave has broken several 2mm cutters prior to his total spindle transplant.

I'm waitiing for a thinner slitting saw to arrive and will try making a new collet to see if that improves the runout on my MF70. If not then I will consider my options again - my rate of breakage is manageable for the work I want my MF70 to do but it would be better if it didn't happen and I could consider running sub 1mm cutters to get into tighter spots.

As I only have a cnc router, not a proper milling machine, a little job came up utilising a 2.00 diameter cutter. The requirement was for square 7.00 and 7.50mm sockets to suit a 1/4" drive ratchet. They do not seem to be available anywhere, so decided to make some from brass (as it was a plumbing job).

Having made a small fixture, the brass blanks 20mm long x 15mm diameter were mounted after through-drilling 5.50mm. A single flute carbide router cutter was used at a feed of 0.5m/min, depth of cut 0.50mm, step over 50% , rpm about 22,000 to machine the square holes 8.00mm deep.

The 1.00mm corner radius was not a problem for the plumbing drain tap, nor the ratchet, so there was no necessity to over-cut the corners.

Pete

.

Very impressive result, Pete

MichaelG.

Hi

I have just been looking through this as I need to cut a couple of bits out of 2.4mm mild steel sheet with a carbide 3mm 4 flute end mill. I have an 1800rpm top speed on my mill an SX3 which is why I am asking as most of you on here are using much faster spindles. I very rarely use such small cutters and I don't really want to start snapping them. It's a slot I would be cutting using the full width. Can anyone give me some idea what sort of depth in mm I should be cutting and at what sort of feed in mm/min? Does it matter if I go shallow depth and feed a bit quicker or deeper and slower feed etc.

Thanks.

Top play safe with a light chip load use say 0.01mm per tooth and do it in 4 passes of 0.6mm deep.

1800 x 4 x 0.01 = 72mm/min feed.

Edited By JasonB on 05/02/2021 20:41:09

I looked up what I did a few months ago on the CNC mill with a 3 flute carbide cutter in hot rolled steel cutting a 4mm wide slot 2.38mm deep. I ran at 5000rpm, 120mm/min feed, full width when roughing and 0.48mm deep per pass. Coming down to 1800rpm and going up to 4 flutes gives a feedrate of 57.6mm/min. Seems I was pussyfooting around.

I hate using small cutters on a manual mill. It's only too easy to momentarily overfeed and then ping!

Andrew

Ok many thanks I will give it a go at about that and hope it survives.

APT is a good firm in the UK supplying carbide cutters and all other tooling.