Author Topic: Lathe Milling Spindle Motor  (Read 6475 times)

Offline tangler

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Lathe Milling Spindle Motor
« on: August 29, 2013, 09:31:07 PM »
Although I have a nice milling machine, setting the dividing head vertically is something of a trial due to restricted headroom so I tend to use the Headstock Dividing Attachment and a milling spindle in the lathe for jobs such as drilling cylinder end plates.  I have a Myford swivelling vertical slide and an Arrand milling spindle and set up using this arrangement:



or this



While satisfactory, this arrangement is a little cumbersome to set up quickly - it would be nice to have a self contained arrangement that could be bolted to the cross slide as a single unit.  The opportunity came with the purchase on ebay of a Myford fixed vertical slide together with another Arrand spindle.  I was then looking around for a small motor of 1/8 or 1/6 HP.  It seems that the days of compact small induction motors has gone and sewing machine motors are usually thought to be a bit marginal in power.  However, I came across this :

http://www.ebay.co.uk/itm/350453897010?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649.
 
This 120W package seems to be widely available from the sewing machine trade (though not necessarily described in such an enterprising manner).  Taking my courage in both hands I ordered one.  I decided to get the package with the foot pedal.

All I had to make was the bracket to hold the motor






Using a the spindle (which has a 1MT) I restrict myself to a 1/4" mill or drill.  So, heart in mouth I did some tests.    I have a cheap laser tachometer.  With the foot pedal fully depressed the speed of the motor alone was 20,000 rpm.  Attached to the milling spindle the no load speed was 4,100 with the supplied 3/4" pulley on the motor and the larger 1.75" pulley on the spindle.  Trying the worst case  I was able to mill a 1/4" diameter slot 25 thou (0.025") deep turning a 2 flute slot drill at around 2500.  Drilling using a 1/4" stub bit again dropped the rpm to about 2500  (1800 with real pressure but this did not feel comfortable).



I am satisfied that the motor is up to the job  and would also be satisfactory driving a small lathe of the Cowells type size.  I don't think the simple resistor speed control offers anything to me, I was just using it as an on/off switch.  Whether a thyristor speed control would be beneficial would be an interesting experiment and I would welcome comments.

I hope these notes may be useful, I'm certainly pleased with the outcome  :)

Rod



Offline Jo

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Re: Lathe Milling Spindle Motor
« Reply #1 on: August 29, 2013, 09:41:27 PM »
 :thinking: Looks interesting Rod.

How about using it on the UPT to power the drilling attachment.. Would it be up to that? It seems to have the necessary speed for small drills. Otherwise like you show in your photos I have a spare Parvalux and it might be destined to power my Xmas present (that I know nothing about  :naughty:)

Jo
Usus est optimum magister

Offline IanR

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Re: Lathe Milling Spindle Motor
« Reply #2 on: August 29, 2013, 09:46:08 PM »
Very nice. I recently bought a somewhat bulkier motor for the same purpose, but at least have the consolation that it was 1/4 the price.
If it's got enough oomph to do light milling, it ought to be plenty good enough for the UPT. Didn't GHT recommend something similar?

Offline tangler

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Re: Lathe Milling Spindle Motor
« Reply #3 on: August 29, 2013, 10:02:23 PM »
I'm sure it would be fine on the UPT.  My original solution was to use the "flying" 1/6HP motor in the first photo, shared between the UPT and the milling set up but, wanting a dedicated motor, I plumped for the cheapest grinder I could find - 3000 rpm is quite a good speed for driving small drills.  Any body want a pair of bargain basement grinding wheels?

One of GHT's options is to fit a motor at the top of the pillar which would be quite neat but it doesn't want to be too heavy - this 120W motor would seem to fit the bill.

Rod

Offline Don1966

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Re: Lathe Milling Spindle Motor
« Reply #4 on: August 30, 2013, 12:19:27 AM »
Rod I just purchased a Bodine 1/8HP 10000RPM universal motor to power my UPT. I will be using my Foredom foot control for the speed control.
This control would work with your universal motor. http://www.grizzly.com/products/Router-Speed-Control-15-Amp/G3703 and this http://www.rockler.com/product.cfm?page=10760&site=ROCKLER

Don