Union Tool Cutter / Grinder Motor replacement?

[Mark Simpson 1Participant @marksimpson1]

I bought a part rebuilt Union Tool cutter /Grinder from a well known auction site. With the need to be able to sharpen Endmills, Slotdrills MT drills, and hoping to be able to do a little surface grinding; there was a 10" x 5" mag chuck with it Typical Photos here http://www.lathes.co.uk/uniontool%26cuttergrinder/

Built a new universal head, that takes R8 collets, and managed to make usable a tupperware of 1/4" – 3/4" cutters; finish was not so great on the bigger cutters so investigated the motor (3 Phase squirrel cage)… All I had previously done was to shim it horizontal to the work table.

The bearings are single row ball races, on a bent shaft that used to be 5/8, but now .005 – .007 less than that and sort of ellipical. There were no seals on the shaft other than the endcaps (now also oversize and oval). End float was removed using two wavy shim washer…All of this was full of congealed oil and grinding dust; very effective grinding paste – It's stuffed.

I've seen the wonders than John Stevenson can perform, but it will cost me as much for the bearings, seals, and a heap of time to have a working 40 year old motor.

Any good reason why I don't buy an off the shelf foot mounted motor, with dust seals and make a new mounting plate? It would also mean that the ability to rotate the motor wouldn't need bent spanners, a torch and skinned knuckles (the bolts are inside the motor mount!).The Worden uses such a motor.

Single Phase would also save the use of my inverter for the lathe and mill,it's only need 375Watts and the original was single speed.

I am sure this forum will now tell me what I'm failing to see Thanks in advance!

p.s. I know I would not be restoring it to it's former glory, but it might standa chance of being more useful!

[Mark Simpson 1Participant @marksimpson1]

Should I have the existng motor rebuilt or replace it

[DustyParticipant @dusty]

Mark, you purchased the machine to use, not as a restoration job. I would buy a new motor, you can have it up and running again in a few days. I do not know much about lectrickery other than if you grab the end of the red wire it hurts. I am given to understand that 3phase will give smoother running than single, which in the case of a grinder is usefull. I am sure that there are many on here that are better qualified than me to advise on the relative merits of the two types of motor.I would suspect that the cost of refurbishment is equal if not greater than buying new.

[Les Jones 1Participant @lesjones1]

Hi Mark,
From the picture shown in your link it looks like the motor has a none standard shaft with threads to take the grinding wheels. You may even find is difficult to get an off the shelf motor with the shaft comming out of both ends. Buying a good quality bench grinder may be the best way to get a motor with threaded ends on the shafts.

Les.

[Mark Simpson 1Participant @marksimpson1]

Thanks Les and Dusty.

One ended will be fine,but had anticipated stripping motor and threading the end as I have a stack of 1/2" UNF wheel adaptors already made. A bench grinder is a great suggestions Les, and the centre height would be about right as well

I'll keep the old motor anyway, incase I sell it on!

Cheers!

[Les Jones 1Participant @lesjones1]

Hi Mark,
You may have a problem getting a motor without a keyway already cut in the shaft. You would probably need to buy a size 71 motor as these have a 14 mm dia shaft that is 30 mm long. If you decide to use a bench grinder try to find a place where you can try it in the shop to make sure it is well balanced.

Les.

[Ray LyonsParticipant @raylyons29267]

Hi Mark,

I have a similar grinder but mine is fitted with a single phase motor with a very old type rotary switch mounted on top of the motor. I have seen photos of one which has been converted using a bench grinder. Don't know about the electrics but the shafts on mine have one end right hand threaded and the other left handed. Have to be careful to switch the motor in the right direction on start up.

[Les Jones 1Participant @lesjones1]

Hi Ray,
With a left hand thread on one end and a right hand thread on the other you can only run the motor safely in one direction unless the wheel mountings are keyed to the shaft.

Les.

[John Stevenson 1Participant @johnstevenson1]

Mark,

What neck of the woods are you from ?

[Ray LyonsParticipant @raylyons29267]

Hi Les,

On my grinder, the motor can be turned through 180d so that the drive shafts are reversed. I usually use the right hand threaded end for surface grinding to avoid having to set the cutters up to grind on the left side of the machine. With the rotary switch, it is an easy mistake to turn the motor in the wrong direction which fortunately for me,on the very rare occasion has resulted in a loose wheel and not the disaster which could result.

Ray

[Phil PParticipant @philp]

I had similar issues when I rebuilt my Union grinder, another problem is the motor speed is not high enough for the smaller cup wheels. I decided to do my own thing and make a complete new variable speed head for mine.

The head also fits straight on to the Myford cross slide for odd cylindrical grinding jobs.

I also rigged up a head for doing four facet drill grinding, see photo's in album.

Phil

[Ian S CParticipant @iansc]

Phil, that looks quite a set up you have. It's OK to increase the speed of a stone as long as it remains within the allowable maximum revs, nobody wants to see what happens when a stone bursts, if in doubt, err on the slow side.(not aimed at you Phil, but newbies).

Ian S C

[Mark Simpson 1Participant @marksimpson1]

Thanks Everyone, (been away from computer for a couple of days). This forum really helps one think through things (without making as much scrap!)

John: I'm between Macclesfield and Buxton.

Les and Ray: I'm aware of the LH / RH thread issue,a reasonable quality Bench Grinder would solve that, not thought properly about the Keyway (thanks Les) but I imagined making a keyed adaptor to the 1/2" shafts of my exisitng stuff….

Phil: yours looks like a "proper" solution,andhaving the possibility to use it occasionally as a toolpost grinder would add another dimension to my workshop

Cheers, Mark

[Phil PParticipant @philp]

This is what it looks like on the Myford doing a spot of crank journal grinding for a model petrol engine crank made from solid bar.

Phil

[Eric StoreyParticipant @ericstorey80546]

I originally started a new thread with the post below but as you guys must know the answer, can anyone assist me please.

Has anyone got a parts manual or maintenance manual for a Union Tool and Cutter Grinder?

I have the operation manual but this gives little or no information regarding parts and maintenance.

I particularly want to know the assembly of the drive for racking the table from left to right as mine seems to have been altered to a direct drive. I believe that the assembly that the handle fits to should have gears in it. If this is so, what is the arrangement, size of gears etc.

Eric.

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