Author Topic: Lathe motor question  (Read 2012 times)

Offline Eugene

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Lathe motor question
« on: June 22, 2015, 02:46:06 PM »
I plan on bringing a long bed Myford M type lathe back to life, and will start in earnest in a couple of weeks; right now it's in the head scratching stage.

I have to hand a big heavy (very) old dragon of a Birmingham built Higgs 1 HP motor with a built in reduction gear that outputs at 240 rpm. It runs sweetly enough albeit with a bit of rumble from the straight cut gears;  I think it's off a feed auger, it sure smells like it and there is ample evidence of chicken poop! The alternative to using this motor is buying a new one for around £90 something I'd like to avoid if I can.

Q1 Is there any reason not to use a 1HP motor on a lathe that usually has motors of half that size?

Q2 Given that I don't have any pulleys to hand and can therefore please myself what sizes I want // fit, is there anything to be aware of with the low initial speed? M Types top out at about 1100 rpm, bronze bearings and all that.

Thanks in anticipation.

Eug




Offline hermetic

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Re: Lathe motor question
« Reply #1 on: June 22, 2015, 03:28:42 PM »
There is nothing to stop you using it from the Horsepower point of view, it will be on top of the job, that is all. Just because the lathe will function fine with a 1/2 hp motor doesn't mean a bit of extra power isn't sometimes useful, you will certainly not do any damage. The real problem is that the lathe would normally be fitted with a 1440 rpm or thereabouts motor, so this motor would need gearing up 6 to 1 to give you approximately the correct speed on the lathe gearbox, I would look for another motor!
Phil

Offline Eugene

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Re: Lathe motor question
« Reply #2 on: June 22, 2015, 05:39:42 PM »
hermetic,

Thanks for the response.

The M Type doesn't have a gearbox, it's an all belt and pulley arrangement. I have another one in the shop with the original 1946 960 rpm motor, countershaft and pulleys.

I reckon the two countershaft speeds available are (approx, just very rough measurements)  260 and 650 rpm which doesn't seem a million miles from 240. So if I arrange pulleys to give around 1:1 and 1:2.7 ratios from the Higgs to the new countershaft I'm close to the factory issue, subject to better measurement. From there I just need to reproduce the factory countershaft / spindle arrangements.

Probably!  :scratch:

Eug








Online SwarfnStuff

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Re: Lathe motor question
« Reply #3 on: June 23, 2015, 03:19:27 AM »
Go for it. From my extremely limited experience think of the smallest diameter you want to turn and select your top speed ratio accordingly. Bottom end speed would have heaps of torque as I see it. Here speaks a bloke who owns only a 7 x 12 Seig clone so what would I know?  :dremel:  :scratch:
Converting good metal into swarf sometimes ending up with something useful. ;-)

Offline Pete.

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Re: Lathe motor question
« Reply #4 on: June 23, 2015, 05:38:25 AM »
You can't run the M too fast because of the plain cast/bronze headstock bearings. I would not put that large a motor on it either, more like a half horsepower only from the perspective that you could break something, possibly even the spindle, by over-powering a small lathe like that.

Offline appletree

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Re: Lathe motor question
« Reply #5 on: June 23, 2015, 06:21:12 AM »
Very good advice from Pete on both counts, my Little John Lathe needs a motor of a special motor with a low shaft height, I picked up a 3 hp 3 phase one to use with an inverter but ended up buying a 3/4 hp one new as I feared damaging something. I would fear what might happen using that powerful motor especially in back gear, it's all ok until it's not ok.  Just had a quick look at that well known site a firm has some motors sub £50 the listing says collection only but offer Del for £12 lower down. All done for less than £50 I know itís you money but if it was me thats the way I would go. Where are you situated?

see 121682336214 and 121682336379

Offline Eugene

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Re: Lathe motor question
« Reply #6 on: June 23, 2015, 04:10:04 PM »
appletree,

Thanks for the links. I'd trawled Fleabay for days without finding those motors. It was the cock up factor that concerned me with the Higgs; I'll go for a new one for fifty squid, that's not unreasonable.

Eug

Offline Fergus OMore

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Re: Lathe motor question
« Reply #7 on: July 01, 2015, 02:53:46 AM »
Soryy to 'come in so late' but I have been on holiday for a month. Well, I've really been on holiday for the lat 30 years :drool:

Martin Cleeve actually answered this question i 1953. He did and he actually fitted TWO motors to  his ML7.

One was a a full 1HP and the other was a 1/3rd.Of course one CAN run a lathe of this size on a 1/4HP ex washing machine motor 1440RPM and I've done it.

Mine has ( well a S7B) has gone sort of three phase but given a fair wind and tide, it is getting a 1/6th 2880rpm as well.

Really, it is all academic,  if push came to shove , you can pedal a 'M' series with a pedal and pitman. Time to buy a copy of old Sparey- methinks?

OK?

Norman