[RCaffin]

Interesting. For many purposes 0.1 mm would be quite sufficient. Yes, I would agree with the use of a spring pass - I do too.

Cheers
Roger

[extent]

even 10k is pretty low if you've got the right cutters. I think the slowest I run is around 16k with a 1/8" 2 flute, typically run between 20 and 24k with 1/4" Oflute and 2 flute cutters. Plenty of times even then I'm running out of RPM, I wouldn't run larger than a 1/4" cutter though. I don't do any tight tolerance stuff on it that I've bothered checking, but taking a nice light finish pass is mandatory

[RCaffin]

Ah - I am making stuff to work with liquid propane on a semi-production basis. There is no room for mistakes with that stuff. I aim for 0.01 mm accuracy, and get close.
Different worlds.

Cheers
Roger

[Mmpie]

I don't think anybody will be using an OMIO for necessarily tight tolerance stuff. You can make it make parts to within 0.01 as I've done it as mentioned above, that part was the first thing I sold and I was keen to do as good a job as possible, that included measuring the cutter diameter and changing to a brand new polished tool for the finish pass. It was long winded and lasted for about 3 parts and ultimately unnecessary as there was no obvious improvement to the finish anyway.

In terms of speeds I regularly drill between 6k to 10k and mill at 10k+, I usually use a cheap 10mm 3 flute at 10450 rpm because it seems to chatter less than 6mm tools. I used to use 24k with a 6mm single flute all the time which I believe is the reason the bearings started to complain on my first spindle. I have used around 6k on an 8mm 4 flute bit to do a finish pass on aluminium because at the time it was the only tool I had with enough flute length to go full depth. It did it happily without issue (and created a nice finish too).


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[NickB00]

Hey Guys,
Looks like Omio have cut me off from their website and wont let me look around or buy anything.
I may have looked like a serial pest hovering around their website putting items into the cart to see what options
are available for each machine and to see how much delivery would be to Australia over the last couple of weeks.
I have tried to email them but that did not work. Oh well looks like an ebay machine for me unless someone else knows of a
seller of similar quality machines that they can point me in the direction of.
Oh well, its their loss. Not happy.
cheers
Nick

[Mmpie]

Hey Guys,
Looks like Omio have cut me off from their website and wont let me look around or buy anything.
I may have looked like a serial pest hovering around their website putting items into the cart to see what options
are available for each machine and to see how much delivery would be to Australia over the last couple of weeks.
I have tried to email them but that did not work. Oh well looks like an ebay machine for me unless someone else knows of a
seller of similar quality machines that they can point me in the direction of.
Oh well, its their loss. Not happy.
cheers
Nick

Doesn't sound right. They'll be your best friend and promise you the world til you give them money.

Then they'll cut you off.


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[RCaffin]

hovering around their website putting items into the cart to see what options
are available for each machine and to see how much delivery would be to Australia over the last couple of weeks.
I hate it when you have to do that. I tend to leave such web sites and not return.

Cheers
Roger

[NickB00]

Dudes,
thanks for your support but I just tried to buy off them again and it went through.
Looks like they let me in again.
So I just ordered a X4-800L machine with 800W air cooled spindle, with Paypal,
so if they decide to play funny buggers at least I have a chance of getting a refund.
Hopefully though that is not the case, they look like a respectful crowd to deal with,
maybe I just overstayed my visit with them?
Will post back when I get him.
cheers and thanks
Nick

[Mmpie]

Talking of accuracy, it just so happens I had to make something with a bit of accuracy today. The bushings are an interference fit so the holes needed to be about right on. I milled them slightly undersize (9.98mm) to start with and kept skimming 0.01mm off the diameter until a cutter shank that measured 9.998mm could be pushed into the hole. This was rather predictably at 10.01mm. Then I turned the bushings at 10.04mm OD, I didn't really know what size to make them as I've never made anything to fit like this before so just had a guess. Bushings went in the freezer, jig went on the radiator, 20 minutes later voila they fit together nice and snug.

So yes you can do quite tight work with it.




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[zeeflyboy]

Nice. Just incase it helps in future - when I need a super precise hole for eg bushings/dowel pins I tend to mill or drill to eg 9.8mm then run a 10mm spiral machine reamer on a super slow drill cycle (eg 30mm/min) with spindle off and spin the head by hand (lowest rpm on these spindles is still way too fast for reaming).

You can choose your reamer to get the fit you want. H7 will give slide fit, H6 is more of a press fit.

I found a 1500-12,000rpm 80mm water cooled spindle the other day on aliexpress. Bit expensive but tempted to give it a go to open up the possibility of automated reaming and more importantly thread milling.

[Mmpie]

Nice. Just incase it helps in future - when I need a super precise hole for eg bushings/dowel pins I tend to mill or drill to eg 9.8mm then run a 10mm spiral machine reamer on a super slow drill cycle (eg 30mm/min) with spindle off and spin the head by hand (lowest rpm on these spindles is still way too fast for reaming).

Yeah, I would have reamed it if I had a 10mm reamer. I've seen you mention that technique before but I've not actually tried it myself. I usually just do it by hand with a self centring reamer through a guide block or centre the tap wrench on the drill. How much bigger do you generally make your OD than your ID for this type of fit? I could have just googled it I bet in a matter of seconds but where's the fun in that


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[zeeflyboy]

It depends a lot on whether I want the thing back out again....

In this instance assuming that the parts were a permanent fit, I'd probably just go for 10.02mm OD on the bush for a drive in fit on the 10mm reamed hole.

I bought a really nice set of H7 carbide spiral machine reamers from aliexpress in the last sale (6/8/10/12mm) and they have been great (these here)

[Mmpie]

It depends a lot on whether I want the thing back out again....

In this instance assuming that the parts were a permanent fit, I'd probably just go for 10.02mm OD on the bush for a drive in fit on the 10mm reamed hole.

I bought a really nice set of H7 carbide spiral machine reamers from aliexpress in the last sale (6/8/10/12mm) and they have been great (these here)

Yeah, I think it was a little big, I've used the heat and freeze trick with bearings and such many a time in the past and they usually just drop in but these did take a bit of persuading, still pushed in easily enough by hand though.

Nice. I've got 3, 4, 5, 6 and 8 which until now is all I ever thought I'd need. Cutwel do offers on them occasionally. Mine are all HSS as I do it all by hand, not broken one yet (touch wood).

I bet you could rig up a little detachable low rpm high torque motor with a timing belt to drive on the collet nut for stuff like this.


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[zeeflyboy]

I bet you could rig up a little detachable low rpm high torque motor with a timing belt to drive on the collet nut for stuff like this.

Weird, I had exactly the same thought... I even printed out a test pulley for the spindle neck but never got around to sorting out a motor mount.

[extent]

proper torque is important though on the nut, want to make sure you hit the right target.

I remember seeing some carousel setup where the CNC moves in a circle to spin the carousel (which then acts as a wrench) to tighten or loosen the nut. Never researched any further though, just went with the typical toolholder and drawbar setup

[dharmic]

Driving off the spindle would be an interesting balancing act. At least you've got the mechanical "fuse" I guess - the nut will simply undo at a certain torque, you'd want to make sure your cutting torque was well below that required to pop the nut.

[RCaffin]

Doubtful, very doubtful.
I use ER25 on the CNC mill. The spanners for the collet nut are well over 150 mm long. I give them a good heave to tighten them, or the cutter slips. Somehow, I cannot see a friction drive matching that.

Cheers
Roger

[Mmpie]

For reaming it would purely be CW rotation so there'd be no risk of undoing the nut and I couldn't see much use for such a set up outside of reaming. It would also be so slow I don't think balancing would really be much of a factor although deflection caused by the belt tension could cause some issues.

Yeah the neck would probably be a better place to drive it from.

Would be a fun and interesting little project anyway.


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[RCaffin]

I suspect the reamer would slip in the collet.

Cheers
Roger

- - - Updated - - -

I suspect the reamer would slip in the collet.

Cheers
Roger

[Mmpie]

I think there's some confusion here so just to clear it up, we're not talking about using a belt to tighten or loosen the collet nut, but using a high torque low rpm motor with a belt hooked round the spindle neck or collet nut to turn the spindle when using a reamer, instead of having to manually rotate the spindle by hand.

These spindles are fairly useless below 6k rpm or so, and have very little guts at that speed anyway.


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