Motive power for a toolpost spindle

I was just seduced by the marketing figures (see Ketan's post on motors). My experience is based solely on using the 120W motor. I'm pleased to learn that the 90W motors appear to be adequate, there's certainly no lack of torque milling steel with a 1/4" tool in my set up.

Cheers,

Rod

It's similar to Ketan's post Brian. I'm sure I have seen older sewing machine motors that give input current and output power. I spent some time looking around to find something suitable - then suddenly remember a couple of sheep shearer motors I bought some years ago. I only mentioned them as sheep are sheared all over the place so people might get lucky. I'd guess that they are a bit expensive if bought for repairing one.

I bought a much larger one recently off ebay. Didn't know it at the time but when I asked the person selling it some questions they said for sheep shearers and they had been on the shelf for ages so he wanted to get rid of them. Too big and heavy for toolposts but I am not entirely happy about the drive on my Pultra. The other option would have been a treadmill motor - it looks to be cheaper to buy and entire broken treadmill locally than a used motor off ebay. These are over rated in terms of the power they will give. Some put current, volts and power on the plates or labels.

John

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Edited By John W1 on 14/10/2015 17:06:22

I went for a sewing machine motor when I motorised a Potts spindle I made from castings years ago. The motor is rated at 9000 rpm no load which gives a useful 1500/2500 rpm with the pulley castings supplied. The motor mounting is made from a scrap piece of channel attached to a collar on the back of the spindle. The motor mounting will rotate 360 degrees and is locked by a grub screw.

I put aside the Potts mounting base and turned and threaded a parallel end on some square bar so it can be mounted in the QCTP. I can fit it in place in seconds for drilling cylinder covers etc. Using the vertical slide and rear QCTP, it can be set up as a light vertical mill which should be useful for cutting clock gears etc.

Edited By Andrew Moyes 1 on 14/10/2015 21:26:02

As the owner of an unused Potts, that's a very good idea Andrew,

Would you consider doing a brief write-up for MEW?

Neil

I like Les's and Neils geared units on page one.

A while ago I butchered a perfectly good Machine Mart 1/2" capacity air drill to get the reduction unit out of to convert my air tapper to electric.

Reason was, to use it I have to run a big compressor for probably only a few holes so it tended to not get used. Now it's on electric it ready for just one or two holes, also the air one struggled a bit on M12 holes but the electric one can do M14 which is as big as my collets go.

But, and seeing these pictures and thinking about it I have some of these.

Desutter self feeding air drills which to be honest are not worth much second hand.

Plated bit is the gearbox and the black tube behind is the air motor and it sups some and more. Inside the control casting is the air cylinder that pushes the chuck and drive shaft out.

So chop it off behind the gearbox and fit one of these spurious 300w / 350w 450w 500w Chinese C2 / C3 mill motors and control board and you have a very nice unit ?

John, that looks suspiciously like one of these:

It was in a far off galaxy.......................................

The er16 collet holder arrived today. There are only a couple of ebayers selling er16 C16 200mm extensions. I went for the one with a hex nut to avoid special spanners. Much to my amazement the shaft is only a few microns out from 16mm. -5 at one end -1 at the other and a bit of a bulge in the middle that may be +1. The end where the main bearing would go shows the least error.

Only thing is that 16mm bore ball type bearings are thin on the ground. Weird as there are loads of 5/8". There are needle rollers but given how well Pultra bearings last if looked after I am wondering about sintered bronze. Maybe over 16mm bore and include a wear sleeve. That would just need a collar and thrust bearing at the other end. There are plenty of 16mm oil seals about.

John

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Edited By John W1 on 21/10/2015 13:44:48

Edited By John W1 on 21/10/2015 13:45:53

actually they were built in cardiff john so i suppose you are almost correct and for a write up they were made using a cut off saw a myford ml7 and an axminster 25 mill in conjunction with a 6 inch rotary table mounted on an mdf jig for the angled holes.

bri

This little scratch-built lathe includes a neat drive arrangement for the cutter spindle.

MichaelG.