New motor for a Myford super 7

[HollowpointParticipant @hollowpoint]

Hello guys.

A friend of mine is wanting to sell his lathe but it needs a new motor. Can anyone point me in the right direction for an affordable (£100ish?) motor to suit a Myford Super 7. Either single phase or three phase is fine. It just needs to be an easy fit.

Any motor and website recommendations are much appreciated.

[Michael GilliganParticipant @michaelgilligan61133]

Where are you ?

If you can get to North Wales to collect it …you can have the original motor from my ML7R

Caveat … you would need to do something clever with the shaft … the previous owner let it run with a loose pulley, so the shaft will need cleaning-up and a sleeve  making.

MichaelG.

[duncan webster 1Participant @duncanwebster1]

I’ve got one that needs the centrifugal switch sorting, free in Cheshire. If interested I’ll dig it out and check the details.

[HollowpointParticipant @hollowpoint]

Thanks for the generous offers guys! Unfortunately both a bit far away. The lathe does have a motor that could probably be fixed, but he/we are trying to avoid having to spend too much time or effort since it is to be sold. Also it needs to be reliable for the new owner of course.

[DiogenesParticipant @diogenes]

I’ve used a couple of ‘TEC’ brand motors (?some years) – although at the lower end of the market they have been reliable, smooth and quiet.

The last one came by courier from Flowfit Hydraulics, 4-pole, 0.55kw, on a B3 foot mount, which I guess of the kind of thing you are looking for.

Tech Spec haflway down the page. No connection other than as a satisfied customer.

https://www.flowfitonline.com/categories/electric-motors-and-drives/electric-motors/single-phase-electric-motors/0-55kw-single-phase-230v-electric-motor-4-pole-1420-rpm-b3-foot-mount

[egaParticipant @ega]

Hollowpoint:

Are you near enough to Medway in Kent where  I have a “correct” single phase Super7 motor available?

[John HaineParticipant @johnhaine32865]

The next owner might want to fit a 3-phase motor + VFD which will transform the lathe, so maybe rather than spend effort time and money sell it as is?

[southernchapParticipant @southernchap]

As John says, There is an argument for not necessarily jumping into buying another motor.

That said, if that’s all that is problematic about the lathe and it is going up for sale, nothing slashes the desirability of an item like a core part of it non-functional.

John definitely makes a good point about someone wanting to stick a 3 phase motor + VFD on it (although to be fair to the 7 series lathes, their belt changes are about the most convenient on any similar sized lathe, if it’s convenience that’s driving the change from 1 ph to 3 ph), but even someone intending to change out the motor is going to expect a significant markdown on the price.

If you want to sell it with a working motor, maybe an idea would be to preempt the desire to have variable speed, by installing a 3 phase motor and include a cheap VFD.

https://inverterdrive.com/group/Motors-AC/ac-Motor-550W-550-Watts-4-pole-B3-71-TEC-IE3

and

https://inverterdrive.com/group/AC-Inverter-Drives-230V/WEG-CFW100C04P2S220G2

Okay, yes, that’s about £188, so not strictly speaking £100-ish, but the ‘infinitely’ variable speed almost ‘out of the box’ for the buyer, could be quite a draw.

If you just want single phase, then I reckon take look on eBay for used (don’t bother trying to filter by anything other than “single phase” and “induction”, half the sellers don’t seem to know what it is they’re selling, and the variability of the description including HP or Wattage to describe the power, never mind including the number of poles, means you just have to trawl through the listings), or probably more sensibly just use @Diogenes link, as that’s a pretty good deal for a single phase 3/4 HP (0.55KW) 4 pole motor.

[John HaineParticipant @johnhaine32865]

In my experience with a new S7 the high speed range was virtually unusable because of the motor induced vibration. I fitted a TEC motor plus N-T VFD and it became a pleasure to use at high speeds. The variable speed is a bonus.

If the current motor is a single-phase induction motor (which it will be if original equipment) and it isn’t working practically the only things that could be wrong with it assuming a winding hasn’t burned out is the capacitor and/or the centrifugal switch.  New caps are very cheap. What are the symptoms?

[John Haine]

On John Haine Said:

The next owner might want to fit a 3-phase motor + VFD which will transform the lathe, so maybe rather than spend effort time and money sell it as is?

Could you please explain your statement  –

” which will transform the lathe”

to us lower beings of lesser knowledge?

[John HaineParticipant @johnhaine32865]

See previous post.

[IanTParticipant @iant]

I’ve just ordered a new 3ph motor & VFD from Inverter Drive Supermarket, as I know my original S7 motor was not in great shape when I purchased the lathe (many years ago) and although I originally stripped and cleaned it – I’ve been expecting it to croak for some time now.

I ordered a TEC 0.75kw motor and an Invertek Optidrive E3 VFD to go with it (they are discounted at the moment). Thought I’d mention that I had some very useful advice from Peter at IDS about this set-up and also purchased a remote pendant kit, barrel fuse holder (and fuses), a 2m shielded motor cable, together with both plastic and metal cable (EMC) grommets. The whole lot came to just over £400 with shipping and VAT.

That compares very well with the “ready-to-run” solutions avaialble (the best known of which is now well over £800) but this will require some work, as the existing motor is a B56 frame and not B3. However, the new TEC motor is fully sealed. Hopefully an adaptor plate and bored out pulley will be fairly easy to do.

Regards,

 

IanT

 

 

[HollowpointParticipant @hollowpoint]

Thanks for the help guys, I appreciate it. 👍

So I had time this morning to have a better look at the motor and assess the problem/s. The problems were a break in the cable and a dodgy switch. The motor (3 phase btw) now runs as sweet as a nut!

Unfortunately that’s not the end of the problems though. The rubber “resilient mounts” have completely perished making the whole thing rock and move in its mount.

So my new question is, where can I obtain new rubber “resilient mounts”?

[bernard towersParticipant @bernardtowers37738]

As its a 3ph motor it runs much smoother than s/ph so why cant you dissemble the mount and fit two pieces of large rubber hose or large size wiring grommets?

[Grindstone CowboyParticipant @grindstonecowboy]

If you have access to a 3D printer, there’s at least one version on Thingiverse

https://www.thingiverse.com/thing:6140635

Rob

[john fletcher 1Participant @johnfletcher1]

If you visit car component/parts dealers they have some sort of large O rings which are almost identical the ones you show in your picture. A friend of mine fitted a pair two three years ago as his went soft. Not expensive either.  John

[HollowpointParticipant @hollowpoint]

Bumping this thread because I still need help with the resilient mounts!

I tried to find rubber grommets without success.

After reading about a similar problem someone else had, we tried casting the mounts with polyurethane rubber. That was a total disaster! The vendor who supplied the casting kit was totally useless as well.

I then tried contacting “Mouldcraft” who where even more useless! Ignoring my messages for over 2 weeks.

I contacted Brooke Crompton who where great, but didn’t have the parts. They told me to try Massey Colbeck as they took over part of the motor business. Which I did. Unfortunately they only had newer types.

I am at the end of my tether with this thing! 😟

 

[MacolmParticipant @macolm]

I would be inclined to try to find sheet rubber. Cut a strip to wind round to make the rubber bush. It could be two or even three turns at a pinch to fill the space, and get the clamps to close.

[noel shelleyParticipant @noelshelley55608]

Hi I will look at a motor I have and see what’s what but a section of reinforced blue silicon hose may well work and I can send you a section of that OR the miracle product CT1 is a bit like silicon but much stronger and is an adhesive so after careful cleaning a new mount may be moulded.  Noel.

[Dave HalfordParticipant @davehalford22513]

I had an ancient General Electric motor with the same type of mount. I would have thought a car top or bottom hose could provide the material though it would cost nearly half the price of a 1/2hp new motor.

[Charles LamontParticipant @charleslamont71117]

What was wrong with the polyurethane casting attempt? That would have been what I would have tried. For the spiders in some little ‘dog and spider’ shaft coupling I found a 70 Shore compound much too soft, but a 95 was just right. I bought these:

https://www.mbfg.co.uk/pt-flex-70-rubber.html

https://www.mbfg.co.uk/duroflex-95.html

[duncan webster 1Participant @duncanwebster1]

I ran a ML7 with a rigid mounted single phase motor, it was fine. 3 phase would be better.

As you’re selling it why not make some steel non resilient bushes, just tell the potential purchaser what you’ve done

[Grindstone CowboyParticipant @grindstonecowboy]

The ML7 I mentioned the other day fitted with the Machine Mart motor (single phase) has it solidly mounted, doesn’t seem to cause any issues.

Rob

[Nick HughesParticipant @nickhughes97026]

Any help here:-

 

Raptor Supplies

[Howard LewisParticipant @howardlewis46836]

How about finding two rubber O rings of suitable section?

Cut to length, and fit.

That should provide a resilient mounting.

Howard

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