Thread: Hembrug lathe on the way.

Hi all

Ever since i saw Greg Qs hembrug project at Phils some time ago I had been keen to get one but figured it just wouldnt happen, i mean how many could there be in Melbourne. But last week one came up and i grabbed it.

I wont pick it up until the weekend after next but i have already had a good look over it, the big issue is that it has been single phase converted with a cap-start motor which has reduced its speed range from 45-4000 rpm to 170-1800 and only has 8 steps rather than 24.

Originally they had a 3 speed 3 phase motor but details are thin on the ground, Peter from the Netherlands has already offered significant help but i was wondering where i might source a 3 speed motor second-hand, are they as uncommon as i assume?


Also would the speeds be 720, 1440, 2880?

I am reluctant to go down the vfd route as i want high torque at low speed.

Any advice appreciated, will post photos as soon as i have moved it in.

Ralph

I suspect that a 3 speed motor (speeds will be nominally as you have stated) will be hard to find and your best bet may be to try and find one off a wreck in Europe. Other than that specialist motor suppliers like Royce Cross here in Adelaide.

A VFD used with the gear box may not be a terrible thing - with vector control (I think that's the term) the torques on offer can be reasonable, and if you ran it at say 30, 60 and 120 Hz the low end torque loss should not be awful either. Torque is an issue with VFDs when people try to do away with belt/ gear changes all together and run them down at 5 or 10 Hz. 30Hz will get you down to around 100rpm with the motor speed you currently have; lower and you may have to put in a belt to take that down some. It may be worth taking a little bit off the top end if you really need that low end speed. (so if it currently is driven with a 2880 motor and you can get 170 to 1800, with a 2880rpm motor and a nominal VFD range of 30 to 120 Hz you would have 100 to 3174 rpm; if you used a 1440 rpm motor you would have 50 to 1587rpm)

Before making too many plans it may be worth putting a tacho on what you have now - I can't get a range of 45 to 4000 from 170 to 1800 just by putting a factor of 3 in there.

Michael

If you find a source for a 3 speed motor, you won't like the price. But, post it here if there is something out there. I'd like one myself for a project.

I have a 2 speed 3 phase motor in my pallet racking but it's something oddball - 2880/720 IIRC. Came out of an Aciera F3 mill. Not for sale anyway though I'd trade it for a 1440/720 3 phase motor. The idiot who owned my Romanian FUS22 mill before me converted it to a single phase VFD drive and *threw away* the original motor! Aaaaargh. That cost him over $500 on the sale, I was so annoyed about it.

PDW

You share a problem that some Monarch 10EE owners have when they want to replace the noisy motor-generator drive...no gearbox to regain a useful torque range.

If all else fails you can look for a hefty servo motor and drive. That could get you all the speed and torque you need. There was a lengthy thread on PM a few years back showing such a modification.

I replied to your message just now. I am wondering if your machine was a DR-1M (the Philips motronic version)if the speed range went up to 4000.

You can see a lot of AI Hembrug machines on Marktplaats.nl

Greg

Oh...if you need any replacement gears for the reversing system let me know...I think I have five sets.

Greg

Originally Posted by Greg Q

I replied to your message just now. I am wondering if your machine was a DR-1M (the Philips motronic version)if the speed range went up to 4000.

You can see a lot of AI Hembrug machines on Marktplaats.nl

Greg

The Hembrug I saw locally last year at auction was a DR-1LS and that also has the 3 speed 3ph motor that went up to 4000rpm.

I really wish I was in the position to buy it. It got passed in at $600. Needed a little work (stripped fibre transfer gears) and a repaired apron but if I had the floor space and wasn't in a rental I would have loved to have brought it home with me and just worked through it. For the price I still feel it was a steal.

Aha, looks like you found the brother to my machine, sold by the same retailer W Adams, same spec (DR1LS) and also has an antarctic division asset tag. Mine has a lot of wear in the cross and compound, but so did my Macson so heres hoping this isnt too much more difficult to solve. It has been in occasional use by a patternmaker since the early 2000's. I am also going to need to replace at least the leadscrew thrust bearings and do a mighty lot of wiring.

If I wanted to use the original motor speed-change controls (a discrete 3 position switch) would many VFDs have custom inputs for changing the frequency to preset values? I have some spare 3-phase induction motors around but they are all really quite powerful (5 or 6hp) and I would be worried about flogging the single A section belt if it stalled, is that a justified concern?

Thanks for the helpful responses - Ralph

Originally Posted by Hornetb

The Hembrug I saw locally last year at auction was a DR-1LS and that also has the 3 speed 3ph motor that went up to 4000rpm.

I really wish I was in the position to buy it. It got passed in at $600. Needed a little work (stripped fibre transfer gears) and a repaired apron but if I had the floor space and wasn't in a rental I would have loved to have brought it home with me and just worked through it. For the price I still feel it was a steal.

Hmmmm - must have missed that one or I'd probably have bought it as a curiosity piece if nothing else.

Wonder where it went - I'd still like to have it.

PDW

I'm not sure where it went PDW, it was referred to the vendor and I followed up on the Monday after the auction and they advised they had sold it to the only bidder for an undisclosed price.

It was at Mannheim in Brighton. The chucks and quick change tool post were worth the price on their own.

Like you, if I could have just stuck it in a corner I would have but I just couldn't justify it with the cost to move it (multiple times). The bore size was on the small side and the headstock quite long so for my gunsmithing interests it just wasn't really the right lathe and I needed something that worked straight off the bat, not a project with an unknown timeline. But as I said, if I could have stuck it in a corner and tinkered away with it without the need to shift it again (I live in a rental).

I have a few pictures of it but not many of the overall lathe.

Originally Posted by caskwarrior

... the big issue is that it has been single phase converted with a cap-start motor which has reduced its speed range from 45-4000 rpm to 170-1800 and only has 8 steps rather than 24.

Originally Posted by Hornetb

That further confuses me...
If you only have 170 to 1800rpm, it looks like you have a motor that is running at 1440prm and are 'stuck' in the II range - but that should give you 2000-90 rpm. Some of these plates can be rounded off for convenience (so the low range at the end is 45, 90, 180 but further along is 112, 224, 450 - it sort of doubles).
Is the 170 to 1800rpm measured? There can be a difference between measured and nameplate speeds (partly rounding and partly revs dropping under load)

If you arranged auxillary cooling for the motor you might be able to run a 1440rpm motor at 25, 50 and 100 Hz. Motor power has two parts - one is losses in the motor and the other part is the power available at the shaft - so a larger motor will have a higher no-load draw but if you only need 1 hp to do a cut then that is what you will get. The belt will slip & glaze if you throw too much power at it.

Michael

Originally Posted by Hornetb

I'm not sure where it went PDW, it was referred to the vendor and I followed up on the Monday after the auction and they advised they had sold it to the only bidder for an undisclosed price.

It was at Mannheim in Brighton. The chucks and quick change tool post were worth the price on their own.

Like you, if I could have just stuck it in a corner I would have but I just couldn't justify it with the cost to move it (multiple times). The bore size was on the small side and the headstock quite long so for my gunsmithing interests it just wasn't really the right lathe and I needed something that worked straight off the bat, not a project with an unknown timeline. But as I said, if I could have stuck it in a corner and tinkered away with it without the need to shift it again (I live in a rental).

I have a few pictures of it but not many of the overall lathe.

Oh well not like I needed it anyway. And small spindle bores are annoying. I've my eye on a big bore lathe ATM, problem is it's in South Australia and not cheap - overpriced IMO so I'm waiting to see if there's a price movement downwards.

I know where there's a pristine Hardinge HLVH locally with pretty much every accessory. It might come on the market one day. Doubt I'll be bidding on it though as it doesn't suit the sort of work I do. I do know someone who'll run the price right up there.....

PDW

Yeah they only have a 26mm spindle bore, I intend to have this almost permanently set up with a collet chuck and use it for all the high accuracy small stuff. With its cast-in gap I cannot get the saddle really close in to the headstock on my macson without coming off the ways to some extent, and the low overhang of a collet chuck would make this worse, also 1000 rpm is just absolutely insufferably loud on the big gearhead.

Originally Posted by caskwarrior

Yeah they only have a 26mm spindle bore, I intend to have this almost permanently set up with a collet chuck and use it for all the high accuracy small stuff. With its cast-in gap I cannot get the saddle really close in to the headstock on my macson without coming off the ways to some extent, and the low overhang of a collet chuck would make this worse, also 1000 rpm is just absolutely insufferably loud on the big gearhead.

I'm sure they are an outstanding lathe and you'll be very happy, everything I read up about suggested they are excellent. Also very quiet being belt driven. The ones on Youtube are very quiet.

The local one had a good crash. Don't do this to yours

Nice lathe, one of the best, I think you might struggle to find a 3 speed motor, even if you do, it will be over $1000 or more, what it will be is 2,4,8 pole switchable,

The way it's done for two speed motors is to have 8 pole delta, with taps on the middle of each leg of the delta, then you switch from 8 pole to 4 pole by shorting together all the mid points, and you get 4 pole star connection, same voltage twice the speed.

I'm not sure how it's done for 3 speed single winding. It might have to be dual wound.

I measured the speeds but only with a crude RPM meter and watch, your maths are likely much closer to the truth, the single phase motor in it is 1440 rpm I would think. Ill look for a decent quality 1440 3-phase motor in the lower horsepower count, ill post a wanted ad tonight. there is a decent size grill behind the stand for air-in, have to find somewhere to let it out though.