Enco 100-1588 repair

ariyama · Feb 2, 2020

Our high school has a '92 Enco 100-1588 10x54" mill. One of the students called me over, saying is was vibrating a lot. The head was quite warm. After pulling it apart, I found that the top motor pulley was cracked. Inside the cover was coated with belt dust.

The set screw was long gone. I've got a new pulley on the way. I later discovered that the motor shaft is a mess. Look like someone took an angle grinder to it!

The journal at the faceplate has about a thou runout. The low portion of the shaft, where the bottom pulley slides up and down, has about 4 thou runout. I haven't priced out a new motor yet. I'm sure its not cheap, assuming it available. I was surprised when MSC said they had the pulley.

Is the 4 thou runout too excessive?

The keyways are not the best either:

While I have the thing apart, I plan to replace all the bearings except for the spindle bearings. Both belts will be replaced as well.

The spline on the top of the "worm coupling shaft is pretty worn. Not sure it really need replacement though. We almost never use it in low speed.

This is the top shaft,

And the bottom:

Any comments, suggestions etc are greatly appreciated. I'm not a machinist, just a high school robotics mentor who doesn't know not to take stuff apart! My main worry right now is the motor shaft runout.

Oh, one last thing. where is a good source for replacement bearings? They are mostly 6xxxZ. I assume MSC is going to charge me a lot more for them. As you can guess, we don't have an unlimited budget!

Thanks for your help,

Andy

moonlight machine · Feb 3, 2020

ariyama said:
Our high school has a '92 Enco 100-1588 10x54" mill. One of the students called me over, saying is was vibrating a lot. The head was quite warm. After pulling it apart, I found that the top motor pulley was cracked. Inside the cover was coated with belt dust.

View attachment 277466

The set screw was long gone. I've got a new pulley on the way. I later discovered that the motor shaft is a mess. Look like someone took an angle grinder to it!

View attachment 277467

The journal at the faceplate has about a thou runout. The low portion of the shaft, where the bottom pulley slides up and down, has about 4 thou runout. I haven't priced out a new motor yet. I'm sure its not cheap, assuming it available. I was surprised when MSC said they had the pulley.

Is the 4 thou runout too excessive?

The keyways are not the best either:

View attachment 277476

While I have the thing apart, I plan to replace all the bearings except for the spindle bearings. Both belts will be replaced as well.

The spline on the top of the "worm coupling shaft is pretty worn. Not sure it really need replacement though. We almost never use it in low speed.

This is the top shaft,

View attachment 277475

And the bottom:

View attachment 277477

Any comments, suggestions etc are greatly appreciated. I'm not a machinist, just a high school robotics mentor who doesn't know not to take stuff apart! My main worry right now is the motor shaft runout.

Oh, one last thing. where is a good source for replacement bearings? They are mostly 6xxxZ. I assume MSC is going to charge me a lot more for them. As you can guess, we don't have an unlimited budget!

Thanks for your help,

Andy

The shaft is toast, time for a new motor. To bad you bought a new pulley, you could have saved the old one by making a steel ring and pressing it on, as long as the bore is good.

cyanidekid · Feb 3, 2020

moonlight machine said:
The shaft is toast, time for a new motor. To bad you bought a new pulley, you could have saved the old one by making a steel ring and pressing it on, as long as the bore is good.

haha! how COULD the bore be any good?? virtually impossible.

try H&W machine repair for the bearings, they seem to sell them for reasonable prices.

ariyama · Feb 3, 2020

moonlight machine said:
The shaft is toast, time for a new motor. To bad you bought a new pulley, you could have saved the old one by making a steel ring and pressing it on, as long as the bore is good.

I thought about doing that, but the bore is no good. I can feel that it is deformed, at least at the top. I suppose I would have had to press a collar on it to know for sure, but it didn't seem likely to me. I'm the only one there to look after the machines. I want to make sure it will continue run for a long time, even if I'm not there to fix it.

ariyama · Feb 3, 2020

cyanidekid said:
haha! how COULD the bore be any good?? virtually impossible.

try H&W machine repair for the bearings, they seem to sell them for reasonable prices.

I will give them a call, thanks. Their videos have helped me a lot, even though the Enco mill is a bit different.

Thanks.

rons · Feb 3, 2020

ariyama said:
Oh, one last thing. where is a good source for replacement bearings? They are mostly 6xxxZ. I assume MSC is going to charge me a lot more for them. As you can guess, we don't have an unlimited budget!

I have gone with Motion Industries for bearings. I could call the local office in my city and they would get the bearings on their regular daily
truck delivery from the warehouse.

SBLatheman · Feb 3, 2020

ariyama said:
Our high school has a '92 Enco 100-1588 10x54" mill. One of the students called me over, saying is was vibrating a lot. The head was quite warm. After pulling it apart, I found that the top motor pulley was cracked. Inside the cover was coated with belt dust.

View attachment 277466

The set screw was long gone. I've got a new pulley on the way. I later discovered that the motor shaft is a mess. Look like someone took an angle grinder to it!

View attachment 277467

The journal at the faceplate has about a thou runout. The low portion of the shaft, where the bottom pulley slides up and down, has about 4 thou runout. I haven't priced out a new motor yet. I'm sure its not cheap, assuming it available. I was surprised when MSC said they had the pulley.

Is the 4 thou runout too excessive?

The keyways are not the best either:

View attachment 277476

While I have the thing apart, I plan to replace all the bearings except for the spindle bearings. Both belts will be replaced as well.

The spline on the top of the "worm coupling shaft is pretty worn. Not sure it really need replacement though. We almost never use it in low speed.

This is the top shaft,

View attachment 277475

And the bottom:

View attachment 277477

Any comments, suggestions etc are greatly appreciated. I'm not a machinist, just a high school robotics mentor who doesn't know not to take stuff apart! My main worry right now is the motor shaft runout.

Oh, one last thing. where is a good source for replacement bearings? They are mostly 6xxxZ. I assume MSC is going to charge me a lot more for them. As you can guess, we don't have an unlimited budget!

Thanks for your help,

Andy

I have a N.O.S. motor from a MSC mill that looks like it could be the same.
Send me an email with the specs and we’ll figure it out.
Ted
[email protected]

DDoug · Feb 3, 2020

Another company supplying aftermarket parts for the clones is High Quality Tools, in cleveland, ohio
High Quality Tools, Milling Machine Parts | HQTInc.com

ariyama · Feb 3, 2020

moonlight machine said:
The shaft is toast, time for a new motor. To bad you bought a new pulley, you could have saved the old one by making a steel ring and pressing it on, as long as the bore is good.

I stand corrected. There is a lip on the end of the bore, but it is on the outside. Sadly the students destroyed the snap gauge I needed to check it properly. With the calipers it looked to be spot on the 1.1 inch diameter of the of the motor shaft. That does not seem possible given the crack. Of course I have no idea how much runout there is. Still, I'll feel better having a new pulley in there. If it were my own machine, not the school's, I might go that way.

What would the acceptable runout be for the motor shaft?

Looking at it more closely tonight, I see the keyways have severely worn sides. So runout is not the only issue.

ariyama · Feb 3, 2020

Worn splines

The the splines the ends of the upper and low coupling shafts are a bit worn; particularly the lower one:

The upper coupling shaft:

You can see the wear were they mate ( they are upside down - lower coupler is on top ):

I think the lower one should be replaced. Upper seems OK.

ariyama · Feb 3, 2020

Experience is what you get....

Yeah, I screwed this one up. I was trying to get the coupler shaft out of the worm housing. The rubber mallet wasn't doing it. Over to the arbor press.

Then the "oh crap" moment, when I realized I bent what I think is a "spring shim" on the part diagram. I wedged in hard enough that the only way to get it out was to cut it. The damage was already done!

Experience earned

john.k · Feb 3, 2020

Despite the peanut gallery ,such things are a simple repair for anyone with a lathe.....skim the motor shaft till its true,sleeve the break in the pulley boss ....bore the pulley boss until the bore is clean .....make a split bushing for the gap, and find or make a wider key and fit it ....press it all together with loctite used liberally.

ariyama · Feb 4, 2020

If I had a bigger one

john.k said:
Despite the peanut gallery ,such things are a simple repair for anyone with a lathe.....skim the motor shaft till its true,sleeve the break in the pulley boss ....bore the pulley boss until the bore is clean .....make a split bushing for the gap, and find or make a wider key and fit it ....press it all together with loctite used liberally.

John,

If I had a big enough lathe, I would tackle it. The school only has toy lathes. Hmm, I might be able to do the motor at home in my 10" unmentionable. I'll disassemble the motor tonight and see if its possible. Guess I can't make it much worse. I could tig weld the keyway and mill back to size. There is a splined adapter that is keyed on the inside. If I enlarged the keyway in the shaft, I'd have to do it it on that as well, potentially weakening it. Tigging the shaft would likely warp it more tough.

Thanks.

Andy

john.k · Feb 4, 2020

Have a look at an advice bulletin for green loctite and loctite key repair. ...there are lots of suggestions for fixing just such a situation .

ariyama · Feb 5, 2020

john.k said:
Have a look at an advice bulletin for green loctite and loctite key repair. ...there are lots of suggestions for fixing just such a situation .

John,

Loctite 660? Found some videos on it. Looks pretty good.

Thanks,

Andy

ariyama · Feb 5, 2020

Motor shaft

We pulled apart the motor tonight. After we pressed the bearings off, I checked the journals. Well under a thou runout. I didn't have a tenths indicator handy, but I would guess about half a thou. That gives me a good reference surface. I think it worth trying to turn it down, build it back up with the tig welder, and any down to size. If I fail, I end up getting a new motor, which I was going to have to do anyway. Either way I'll learn something in the process!

The next step is figuring out what filler metal to use.

(photo taken after the fact)

This is the splined collar that goes on the shaft. Pretty beat up, and loose on the shaft. I'll try to get a replacement.

There is a plastic mate to that that fits in the bottom pulley. That is quite worn too. Another thing to replace.

Gordon Heaton · Feb 5, 2020

Did you see post #7? I'd start there for the motor problems!

ariyama · Feb 5, 2020

Gordon Heaton said:
Did you see post #7? I'd start there for the motor problems!

Gordon,

Yes, I contacted Ted and he kindly measured his motor. It looks like a close fit, I'd need check my numbers again. His motor is a 2HP, while mine is 3HP. I'll proceed with the repair for both the challenge and the experience. In a commercial setting it might not make sense, but for the school, we have more time than money.

Thanks,

Andy

tnmgcarbide · Feb 6, 2020

if the flange and shaft fit i wouldn't be too critical of 2hp vs 3hp . in the 90's , there were many machines
boasting optimistic hp ratings which included "peak"
and "15 minute duty cycles" . even a real BPT today isn't completely innocent of the practice .

putting a slightly smaller hp motor might be to advantage- less wear and stress on an old
machine , which was already junk the day it left the factory .

Guest · Feb 6, 2020

As for bearings if you haven't bought them yet sometimes you can find great deals on Ebay for high quality precision bearings. I scored a matched set of spindle bearings, name brand that are $400 a set at the cheapest from bearing suppliers for $35.

Enco 100-1588 repair

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