DSG Motor, again.

Hello all, a few months back, I asked about the electrics on my DSG13/30 lathe, well I have another question, this time about the motor.When I bought the lathe , a new 5 hp TEC motor had just been fitted at the factory that previously owned it and to cut a long story short, had fitted it very badly.Not only sloppily bolted to a bit of plate on 3 spacers, the 4th perched on the lathe bed below the headstock, ???. The drive pulleys were 3/4 inch out of line, but worse, the pulley was loose on the motor shaft.

The new motor shaft size is 28 mm, the old, 1 3/8inch, just over 1/4 inch smaller. Im just in the process of trying to get the mutilated pulley off. It looks like the chap (##ob) sawed 3 inches off the old motor shaft, bored it out 28mm, but oversize !!, bashed it back into the pulley and ploncked the whole lot onto the new shaft, drilling through the " new" reducer, and securing it all with a grub screw. Ive got a nasty feeling that the shaft has been damaged by the pulley being secured axially, but loose.Because he mangled the pulley boss fitting it to the bit of old shaft, its on that bit rather tight !!.Right, to the question, to have saved all this heartache and disgusting language, are there reducers or adaptors available for the changing old motors for new ?. I emailed TEC, but had no reply. Many thanks.

In short no.

Motor suppliers and rewinders either have their own machinists that can do this or farm it out.

I do literally 1,000's of such conversions per year [ no typo ] and for someone geared up to do this it's a very simple job.

Where are you located Roger ?

Hello John, thanks for replying. Im located in Teignmouth, Devon. Im not a machinist myself, so am a bit unsure the best way to do the job, presumably some sort of bush with a key slot on the outside and another on the inside, a bit beyond me I think !. Ive got machines to have a go, but thats as far as it goes. Now if you fancy an ice cream, and a look at some half decent motorcycles !!!!!!!! Roger.

That's an expensive ice cream !!

Pictures of the existing shaft and pulley would be nice as there are always different ways to attack these, maily depending of damage.

Taper lock bush system is the quick "professional" answer to this sort of problem. The system uses a split bush with parallel bore and taper outside. The pulley has a matching taper bore into which the bush is driven by cunningly arranged screws thereby causing it to contract and grab the motor shaft. Hard! There is an equally cunning extractor arrangement.

The system is, apparently, by no means as spendy as it used to be. For example the Bearing Company offer bushes and pulleys at relatively reasonable prices. See http://www.thebearingcompany.co.uk/product.php?id_product=5293and http://www.thebearingcompany.co.uk/category.php?id_category=29. There are plenty of other suppliers, not to mention a certain auction site. (Heck I may have one on the white elephant shelf as I bought wrong size in error some time back and had to get a different size but whether 28 mm was the right or wrong one I dunno!)

Obviously a suitable pulley needs to be available. The range is wide, but not exhaustive, so some compromise on speed may be needed.

Clive

PS sorry can't get the link to truncate.

Edited By Clive Foster on 11/05/2013 13:15:08

Edited By John Stevenson on 11/05/2013 13:54:00

Sorry Clive I can't either ?

Yes taperlocks are ideal but there is a limitation on what will fit where. The 1610 has an OD of 2.25" and more is needed for the screw holes so unless the pulley is more than say 2 5/8" across the bottom of the belt vees, they won't fit.

They will even fit damamged shafts if still running true as thay will close up a good 12 thou or so.

Hello Roger,

As Clive says, taper lock fittings are very forgiving and I have used such fittings on agricultural drives many years ago with success.Certainly worth looking at

I am always saddened to hear of grotty workmanship like this waiting for a new owner to discover and put right, very unfair. I can't help you directly either with living in North Yorkshire and would want the ice cream factory as well travelling from there!

Regards Brian

Hi Roger

If you are looking to learn how to use this fearsome beast, making a decent adaptor would be an ideal starter project.

All you need to do is use a shortend of steel some 1/4" larger than the pulley bore. Bore it to fit the shaft and turn the outside to a press fit in the pulley. Part off leaving a short flange at full diameter.

To sort out the keyway just cut a neat slot in the tube you have made, but not the flange. Press into the pully with the slot aligned with the keyway. Or turn it undersize and use a retaining compound to hold it in the pulley (this may be easier). You may need to use a new, slightly deeper key.

Neil

Hello, thanks everyone for the replies. Ive managed to get the pulley off, 8 inch diameter by the way, and it was very tight, leading me to suspect that because of the damage ie, big hammer marks on BOTH sides of the pulley, he couldnt remove the pulley from the old motor shaft, so he just chopped it off, with 3 inches of shaft still inside it, somehow bored it out. If it was the original motor, it would have been on there 52 years !. I will try and post some pictures when I get the " adaptor " off. Another thing that shocked me, excuse the pun, about the job, was that out of the many stranded earth wire connection on the new motor housing, only 1 strand was between me and death. By the way John, you say you do thousands of these conversions, how exactly do you do them ?. I think I will end up doing it as Stub suggests unless you can show me an easier way.Again , thanks to all for your help,

Roger.

Roger, will post in more detail later but do you have provision the machine this 8" pulley whilst it's off the motor ?

Or do you need the pulley to drive the lathe ?

Don't underestimate the frustration factor involved when setting up a "distressed" pulley to run true for re-machining. If you haven't got a good bore to pick-up on a good deal of creativity may be needed.

What size belts? I have a couple or three 8 inch pulleys about the place which I shall never use, including a nice double B sheaves taper lock fitting one, which could be re-homed for a modest number of drinking vouchers.

Clive

Hello again, thanks for offer Clive, John, yes I would need the DSG to machine the pulley. I have a Hardinge HLV-H as well, but wouldnt be able to do it on that. Anyway, an update on the saga. Ive removed the old bit of motor shaft and it certainly looks like he chopped off the pulley and shaft as one.Ive put some photos in my album and you can see how he seems to have bored the lot together because of the machine marks on the key !. You can also see the dings on the pulley as well. What I dont understand though, is there is a 10mm by 1.5 mm pitch thread in the end of the new motor shaft, so why didnt he drill a hole in the old shaft bit, and pull the " adaptor " up to the end of the new shaft, with some bearing fit Loctite, with a nice Allen bolt. To my mind, if he had used his brains, it would have been OK. For extra security, perhaps another grub screw opposite the other one. So what do you all think, make a new sleeve with a tighter fit , a keyway for the pulley, and go from there ?.Hope you can see from the photos what Im on about. By the way John, even if I could modify the pulley for a Taperlock, I would only have one go at it, so if I made a mistake, I would be in deep s*it. Regards to all, Roger.

Yes new sleeve, better fit and pull it up with the central bolt.

Definitely use another grub screw and go 90 degrees to the existing one and go over the key to force it into the keyway. I can never understand why people force onto a shaft.