Do many people run 2 Milling Spindles

[Alan KinseyParticipant @alankinsey80963]

My extra router spindle gives me up to 24K RPM as my CNC converted mill was limited to 2250 before. Good for 3D scanning! I added counterbalance weights to offset extra weight.

[Alan KinseyParticipant @alankinsey80963]

[BufferParticipant @buffer]

Alan, I don't but I have been thinking of doing this for some time on a sieg x3 that I have converted.. Could you put up the details of what you are using and how it's going etc. Thanks.

[Anonymous]

Short answer is yes. The main spindle on my CNC mill goes from 100 to 5100rpm in two overlapping ranges. For small cutters I have added a high speed spindle that goes to 24000rpm .

Andrew

[Phil PParticipant @philp]

I cobbled up a die grinder onto my Alexander mill if that counts.

[David George 1Participant @davidgeorge1]

I ran my spindle to engrave a dial and the spindle was getting very hot so decided to make an engraving spindle mounted to one side of the spindle.

David

[JasonBModerator @jasonb]

With 5000rpm from my spindle I've managed so far and as I seem to do more work with steel and iron than aluminium I'm not that far below optimum speed for most of the cutters I use. I have engraved and cut ali without problem if a little longer run time

If I do much more pattern making then I would consider it as there is usually a lot of small stepovers for that combined with being wood or aluminium I cut from it would speed things up. I've a Makita Laminate Trimmer that would be easy to fit provided my ears can take the increased noise.

I'm not sure how it would be at long run times as it is generally quite short amounts of use that it usually gets, certainly not water cooled like yours looks to be

[Les RileyParticipant @lesriley75593]

Not two spindles on one machine but two separate machines. Small converted XY table with Kress router on the Z for engraving and small work. A Bridgeport Interact converted to Mach 3 for heavier stuff at slower speeds.

[Iain DownsParticipant @iaindowns78295]

What a fine idea (David George 1). I'd been wondering about adding a spindle to the side of my biggish mill, but it won't quite fit.

This is a great way to get high speed for the occasional need.

Iain

[John ReeseParticipant @johnreese12848]

My RF45 mill is limited to 1500 RPM with the 4 pole motor supplied. Small diameter cutters work best at much higher speed. I have been considering adding a high speed spindle to use the small cutters efficiently.

[RobinParticipant @robin]

That's the trouble with machine video's on YouTube… Everyone else's machine looks better than yours.

Helps if you ask yourself how they would cut a 20DP gear in cast iron

[JasonBModerator @jasonb]

Posted by Robin on 08/02/2023 12:54:52:

That's the trouble with machine video's on YouTube… Everyone else's machine looks better than yours.

Helps if you ask yourself how they would cut a 20DP gear in cast iron

Not sure what videos you are talking about as no mention further up the thread?

However if it was how someone with a high speed spindle may cut a 20DP gear in CI they have a few options

Cut it with the gear vertically using a small dia ball nose cutter after first roughing, manual or electronic 4th axis. Or depending on thickness cut it horizontally, again rough out and then finish the roots with a small cutter no need for a means of dividing..

Biggest advantages of doing it that way is you can get the correct involute for the number of teeth and not one that falls into the range of involute cutters, you can cut any pressure angle you like and one cutter does all so no need to keep buying a cutter for every DP, MOD and Tooth count or any tooth profile that you need to cut

Edited By JasonB on 08/02/2023 13:23:04

[John HaineParticipant @johnhaine32865]

I'd really like a higher speed than 5000 rpm on my Novamill but the table is too short to add an auxiliary spindle to the side as I would lose quite a lot of X travel.. As it has a BT30 taper and 12mm spindle bore above that I have toyed with the idea of a subsidiary spindle with bearings in an adapted taper and a coaxial shaft to the top of the existing spindle so the drive motor fits on top. Has anyone seen anything like this please? The alternative of a motor and spindle beneath the head wouldn't work because there isn't enough headroom.

[John HinkleyParticipant @johnhinkley26699]

John,

Would it be possible to incorporate a captive spindle in a BT30 shaped housing and mount a high speed motor alongside the head, driving the spindle via a belt and pulleys? That way, you can preserve the table motion limits at the expense of a little headroom.

John

[John HaineParticipant @johnhaine32865]

Thanks John – telepathy at work! I was just standing in front of the machine and thinking the same thing! Actually looking at a typical BT30/ER16 chuck I needn't lose too much headroom. Now how do I design a captive spindle….?

[JellyParticipant @jelly]

Posted by John Hinkley on 08/02/2023 16:48:53:

John,

Would it be possible to incorporate a captive spindle in a BT30 shaped housing and mount a high speed motor alongside the head, driving the spindle via a belt and pulleys? That way, you can preserve the table motion limits at the expense of a little headroom.

John

 

 

That sounds very do-able and quite neat.

 

You can buy replacement spindles for Taylor-Hobson pantographs which will take straight shank cutters up to about 8mm, about £700 and good to 30k RPM.

They're a sealed cartridge design intended to be modular, and come with three speed pulleys for round PU belting machined into the spindle.

The cartridge is slightly too long to fit inside a the body of a BT30 taper, and leave room for a drawbar thread (pull stud would be ok if machined from solid), but the shell is rigid enough that you could clamp one in an ER32 collet without any drama, only losing about 1" of headroom for the pulley.

Add a brushless motor in a bracket which clamps to the spindle nose and you'd have a *very* good high speed spindle from commercial off the shelf parts!

 

That said when I last needed a spindle like that, I made my own with a high precision ER11 straight shank holder from APT, some bearings from Accu, and a shell and pulley I machined myself.

I still have the drawings and cad files somewhere if anyone wants to adapt them (the obvious thing to do would be buy a blank BT30 taper and bore that out as the shell of the spindle).

Edited By Jelly on 08/02/2023 17:23:41

[John HaineParticipant @johnhaine32865]

Jelly, I think the TH option is a bit pricey, but I'd be very interested in your design if you could share it please.

John.

[simondavies3Participant @simondavies3]

I do as well – I locate the 2nd HSS spindle using the main MT2 bore so that high speed (~12000rpm) and low speed (2450rpm) are co-located in X and Y planes.

Like this (apologies for the enormous amount of clutter!):

[Author]

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