Alpine model DM20 mill/drill

[keith davisonParticipant @keithdavison69089]

Can anyone help I have purchased an Alpine DM 20 and require some spares parts. Also a manual or copy of one.

I am a total beginer . So what I think is wrong . Backlash in the X , Y hand wheels.

Drive motor on the bed.burnt out. Are these obtainable.

And would anyone have a wiring diagram for a Forward and reverse setup with I think micro switches fitted to limit travel.

Thanks.

[keith davisonParticipant @keithdavison69089]

User manual and spare parts

[RobboParticipant @robbo]

Probably one of the generic "Taiwanese" mill drills. Have a look at the Rong-Fu 20/25 here **LINK** and see if it looks familiar.

Or have a look at Grizzly.com and select a similar looking from their mill list. they have manuals for lots of machines sold under various names.

If this is the one in Wigan which was on ebay recently, then as far as I recall the seller said the power feed was not wired up but could be run from a separate supply.   If its knackered then that's misdescription.

I looked at this one and considered it, but having had a similar mill once I bought something else.

Edited By Robbo on 09/05/2015 09:35:29  – why can't this computer spell??

Edited By Robbo on 09/05/2015 09:49:45

[MuzzerParticipant @muzzer]

The feeds I've seen for the generic mill/drill are basically the same as sold for Bridgeport-type milling machines, with an adaptor to fix them on the end of the mill/drill table at 90 degrees (so they don't hang down and get in the way).

The power feeds are generally designed for 120Vac, so it's entirely possible someone has "tried" it on 240V with inevitable results.

If so, IIRC, John Stevenson recently gave details of a place in the UK that keeps spares for these drives. Whether or not it's worth trying to repair (ie swap the electronics) is your call but the backlash is a matter of adjustment presumably.

Murray

[MuzzerParticipant @muzzer]

Typical manual here, with circuit diagram on page 11. It's a little confusing until you realise that all the diode symbols are missing their triangular elements (4007, 5404 etc). Looks as if the semiconductor devices are all SCRs (2) and diodes, with a sprinkling of caps resistors, VDRs etc.

It's possible that connecting to 240V would blow the fuse without damaging the active devices. If so, make sure to replace the fuse with one of a similar speed and current rating.

[keith davisonParticipant @keithdavison69089]

Thanks all for the responces. Robbo It is the machine from Wigan and I was aware that the power feed was not working and was not expecting to use it . It did operate when I picked the machine up but was smoking, it only motored in one direction on the x axis, travel was limited via a micro switch . Sorry I did mention the X & Y but the drive is only on the X.

I stripped the cover plates of today and had a look It is a 230/250 volt motor with a reduction gear box it drives a gear attached to the right hand side of the bed where the hand wheel use to be. The drive is engaged / dis engaged by a manually sprung pin . The handwheel on the left of the bed is used to operate the bed manually.

I sripped down the motor and the insulation had failed on one of the windings end wires and am unable to repair this. It is an old style motor so could be re-wound if these are not available anywhere .?

The motor has the start and run windings wired out so could be wired to run in both directions. I cannot understand why this was not done. There is no speed control.

All in all do you think someone has just put this together.?

Also I have an ABB electronic motor controler. Has anyone used a digital controler on the main motor I suppose it just takes away the effort of changing belts. ?

[Clive FosterParticipant @clivefoster55965]

Unidirectional power feed is a strong indication that a basic commercial motor and gear unit has been adapted to drive the table. Any commercial feed drive would be bidirectional but if going DIY single direction operation avoids the complications needed to ensure that the motor has to be reversed if its up against the limit switch. Simple enough with low voltage DC motors if you understand diodes but a 240 V motor needs relays or, better, contactors to safely control the higher voltages. Is there a brand name on the motor?

Consensus seems to be that a car windscreen wiper motor does an adequate job at the power feed business for these small machines.

You will need to swop out the single phase motor for a three phase one to use a digital VFD controller but the effort is well worth it. My slightly larger square column mill came with a VFD controlled 3 HP motor and two speed belt drive. Speed ranges were 125 to 1400 and 250 to 2800 which were quite acceptable in use as the considerable overlap in the middle meant that the belt position rarely needed to be altered. Good thing too as it was a right faff to do. That said a lower bottom speed, say 50 rpm or so wouldn't have gone amiss. The reduced overlap would not, in practice have been much of a worry. The VFD driver box was inside the casting with no speed display. Just a plain knob on a potentiometer with no markings on the head front panel. I replaced the plain knob with a skirt type collet knob from RS Components having 12 clearly numbered divisions on the skirt. A laminated label stuck to the front of the machine translating the division numbers into speed settings for each of the two ranges made it very easy to set the desired speed. Frankly I actually preferred that basic system to the common digital speed display..

Clive

Edited By Clive Foster on 09/05/2015 21:46:19

[MuzzerParticipant @muzzer]

The DIY power feed has been a few times on this forum. Here's some pics of the one I did. I used a 24V window winder and a 0-30V bench PSU from Rapid Electronics (similar PSUs are available from Maplin).

Not sure if it's really worth putting a VFD and 3-phase motor on it. Personally, I'd save the money and use it to buy something bigger, if anything. It's already got plenty of speeds available and the limitations are more to do with its size and rigidity. It's a start though.

Murray

[RobboParticipant @robbo]

The power cross feed motor was a Parvalux, a name that sticks in the mind. They often came with nifty built-in gearboxes/right angle drives so would be ideal for the job, except for being mains voltage – though some were low-volt.

So I guessed the power feed was a home brew.  Also it was fitted to the right hand end of the table, most commercial drives I have seen have fitted on the left.

As the OP states "I am a total beginner" I would suggest forget the power feed and conversion to 3-phase for now, and just get on with some milling, having cleaned and adjusted the machine.

They can do good work, when I got my old Ajax version it came from someone who had used it for 20 years building locos. He sold it as he had the offer of a dovetail column mill, the round column being a bit of a drawback.

Edited By Robbo on 10/05/2015 09:15:25

[Author]

Posts