# How can I straighten a large cast pulley?



## bpimm (Sep 11, 2019)

My compressor just flipped another belt, the pulley on the compressor head has about .5" of wobble and I think that's what's causing the belt to give up, only happens every couple years but I thought it was time to see if I can fix it.

There is no ID tag on the compressor head but the name plate on the mounting plate says Kellog Model EM33-E. The shaft is strait, I put an indicator on it and turned it over by hand so the wobble is in the pulley. My original thought was to bore out the center and bush it back down to the shaft size but my lathe isn't big enough to grab it by the outside. the pulley outside diameter is 22.5". After getting the pulley off the compressor I'm not sure if I can do the bore and bush because the hub has a thin extension on it that might be compromised by the bore.

Any suggestions for straitening this thing out? I have a HF 12 ton press and a porta power to work with.


----------



## kvt (Sep 11, 2019)

Yours is in better shape than mine,   It also has a wobble and has for as long as I can remember, it is the same one that my dad had on his truck for fixing large tractor flats.   don't remember it ever throwing a belt.  Mine was built about 1966


----------



## pstemari (Sep 11, 2019)

What sort of belt does that take? It doesn't look like a normal v-belt. Ordinarily, I would just suggest buying a new pulley, but I'm not sure where I look for one of those. Maybe SI-SDP?

Sent from my Pixel XL using Tapatalk


----------



## matthewsx (Sep 11, 2019)

Obviously you need a bigger lathe to do this job

Seriously though, if you can't resolve the issue with adjustment I would be reluctant to do anything. A part like that is under more strain than I would like to mess with, at the very least consult someone with real experience in the field before attempting anything.

JMHO....

John


----------



## bpimm (Sep 11, 2019)

I think it is just a standard 5/8" v belt, just 4 of them. I've only been running 1.

Kvt the only date I can find is on the tank and it's 1936


----------



## fixit (Sep 11, 2019)

If you put pressure on that pully to correct the wobble it will BREAK!  I would mount it on a known true shaft to verify the crank is not bent, I have seen mang bent crankshafts. If it wobbles & the crankshaft is true then it's a machining problem & was that way from the get-go. How many belts do you run on it? There is paint in the belt grooves. Have you used a POLY BELT? Checked belt alignment?

Just saw you only run one belt, I would almost bet if you used 4 MATCHED  belts or POLY-BELT problem would be solved. Just my 2 cents.


----------



## MrWhoopee (Sep 11, 2019)

That job needs to be done in a mill. Bore and braze a bushing in, then finish bore.


----------



## matthewsx (Sep 11, 2019)

They built it that way for a reason, try more belts. 

It's unlikely the spec requires it to run very true, as long as it's driving the pump it's doing the job it was designed for.

John


----------



## MontanaLon (Sep 11, 2019)

When you say "wobble" do you mean axial or radial? Simple English is is moving side to side in line with the motor or is it moving in the direction of the belt travel? 

The first could be a casting flaw that can't be corrected or it could be a misaligned bore which could be fixed. The second would be an off center bore which could be fixed. 

My guess for why you are running it with one belt is that the pulley on the motor you have only has one track. It would actually be easier to make a replacement for that with 4 tracks and run it with 4 belts.


----------



## Chipper5783 (Sep 11, 2019)

Does the wheel appear to be damaged?  How old is this machine?  Perhaps it has been like that since day #1.  Granted it would be nice if your drive belt didn't jump off from time to time - but I'd have a go at playing with the alignment, play with the tension, try a couple different types of belts.  I agree it would be nice if the flywheel ran mostly true - but don't wreck it trying to fix what isn't really broken.

I have a 5HP compressor with a flywheel about that big - it has two grooves but it only had one belt on it when I bought it 18 years ago - it was far from new then (I'm still running the same belt it came with).


----------



## FOMOGO (Sep 12, 2019)

I'm guessing it was knocked over or dropped while being moved, and was bent. Close inspection by mounting on a straight shaft (or just back on the pump if your sure the crank is true) with a pointer on the outside diameter would  show where it's out. If it bent one way, I bet it would bend back with the proper setup. The approach Mr Whoopee pointed out would also be an option. Mike


----------



## cathead (Sep 12, 2019)

The pulley was likely straight from the factory.  FOMOGO's inspection idea is excellent!  The blue paint is suspicious
for one thing as the compressor surely started life with multiple belts.  If one of the fan blades were
cracked and repaired and painted it would likely have the aberration you are experiencing.  Another thing, the first
photo looks like the pulley possibly has a sleeve in it.  Could some previous owner have attempted to repair it ?

Putting hydraulic pressure on the pulley could break it so would proceed with caution.  One final thought...If there
is any play when you just slide on the shaft, could you possibly install a thin shim in the right place to lessen the wobble
at least some?  I would experiment with that first as it would be harmless to try.


----------



## bpimm (Sep 12, 2019)

matthewsx said:


> Obviously you need a bigger lathe to do this job



LOL Always.


----------



## bpimm (Sep 12, 2019)

fixit said:


> If you put pressure on that pully to correct the wobble it will BREAK!  I would mount it on a known true shaft to verify the crank is not bent, I have seen mang bent crankshafts. If it wobbles & the crankshaft is true then it's a machining problem & was that way from the get-go. How many belts do you run on it? There is paint in the belt grooves. Have you used a POLY BELT? Checked belt alignment?
> 
> Just saw you only run one belt, I would almost bet if you used 4 MATCHED  belts or POLY-BELT problem would be solved. Just my 2 cents.



Breakage is a concern, but if it bent one way will it bend back? probably not worth the risk.
I tried 2 belts, the motor has a 2 groove pulley but they were not a matched pair and the length difference was to much so I ran the shorter one until it gave up then ran the longer one and now it's given up. I bought a double belt to fix it but I must have measured wrong and it was to long so I tossed it aside and ran it the way it was. I'm in the process of changing the motor pulley to a larger size, should increase the compressor speed about 20%, it's only turning about 325 RPM now, the new pulley will get it up to about 400 RPM. I modified the mounting hardware so with the bigger pulley and more adjustment room the double belt should fit. 

With 5HP compressors running single belts I figured that this would be ok with a single belt, it's a 5 HP motor, I don't know what the compressor head is rated for.


----------



## bpimm (Sep 12, 2019)

MrWhoopee said:


> That job needs to be done in a mill. Bore and braze a bushing in, then finish bore.



I thought about that but without a boring head... but this morning I remembered buying one for a project a while back and then not doing the project, guess I forgot I had a new one on the shelf, 

Now I would need advise on indicating in a 22.5 inch circle on the mill table, I don't think I have enough travel to use an edge finder, I'll need to make something to mount an indicator in the spindle that can reach out a foot.


----------



## bpimm (Sep 12, 2019)

matthewsx said:


> They built it that way for a reason, try more belts.
> 
> It's unlikely the spec requires it to run very true, as long as it's driving the pump it's doing the job it was designed for.
> 
> John



True, but it does cause some vibration/shake I'd like to get rid of if possible.


----------



## bpimm (Sep 12, 2019)

MontanaLon said:


> When you say "wobble" do you mean axial or radial? Simple English is is moving side to side in line with the motor or is it moving in the direction of the belt travel?
> 
> The first could be a casting flaw that can't be corrected or it could be a misaligned bore which could be fixed. The second would be an off center bore which could be fixed.
> 
> My guess for why you are running it with one belt is that the pulley on the motor you have only has one track. It would actually be easier to make a replacement for that with 4 tracks and run it with 4 belts.



It's axial wobble, I guess it could have came like that but I assumed it got hit at some point in it's life and bent.

Pulley on the motor has 2 tracks, see previous answer fir full story of laziness...


----------



## bpimm (Sep 12, 2019)

Chipper5783 said:


> Does the wheel appear to be damaged?  How old is this machine?  Perhaps it has been like that since day #1.  Granted it would be nice if your drive belt didn't jump off from time to time - but I'd have a go at playing with the alignment, play with the tension, try a couple different types of belts.  I agree it would be nice if the flywheel ran mostly true - but don't wreck it trying to fix what isn't really broken.
> 
> I have a 5HP compressor with a flywheel about that big - it has two grooves but it only had one belt on it when I bought it 18 years ago - it was far from new then (I'm still running the same belt it came with).



I can't see any damage but it may become apparent when I clean the pulley, the only date I can find on the machine is on the tank cert plate and that is 1936. The compressor ID plate is attached to the mounting plate on the tank and the welds look factory so I think it's original.

That was my thought process that a 5HP compressor is good with 1 modern belt, maybe in 1936 the belts couldn't handle it.


----------



## bpimm (Sep 12, 2019)

FOMOGO said:


> I'm guessing it was knocked over or dropped while being moved, and was bent. Close inspection by mounting on a straight shaft (or just back on the pump if your sure the crank is true) with a pointer on the outside diameter would  show where it's out. If it bent one way, I bet it would bend back with the proper setup. The approach Mr Whoopee pointed out would also be an option. Mike



That's what I thought, it got bent. but now I'm concerned about breaking if I try to bend it back, Cast does like to break.

I need to put an indicator on it and see how it's bent, the crank measures good. I had a thought, clamp the wheel to the side of the press and then put a shaft in it and push on the shaft with the ram to tweek it back.


----------



## bpimm (Sep 12, 2019)

cathead said:


> The pulley was likely straight from the factory.  FOMOGO's inspection idea is excellent!  The blue paint is suspicious
> for one thing as the compressor surely started life with multiple belts.  If one of the fan blades were
> cracked and repaired and painted it would likely have the aberration you are experiencing.  Another thing, the first
> photo looks like the pulley possibly has a sleeve in it.  Could some previous owner have attempted to repair it ?
> ...



The whole thing was painted blue when I got it, pretty good paint as it held up in the groove with a belt running in it.
I don't think that is a sleeve but I'll know more when I get it cleaned up.

It's tight on the shaft, I had to use a puller to get it off even with the clamp bolt out.


----------



## markba633csi (Sep 12, 2019)

If you have a full size mill like a Bridgeport and a lathe make a short arbor to help indicate the pulley on the table.  Then bore it and sleeve. Lock it in with some super duper loctite or epoxy.
I wouldn't try to straighten cast iron even with heat.
Mark


----------



## projectnut (Sep 12, 2019)

Before attempting to bore and bush the pulley do some more measuring on the compressor shaft and the bore of the pulley.  It's likely the shaft isn't full diameter at the end, and the bore is oversize.  I also have a Kellogg compressor that at one time had a similar wobble at the pulley.  I researched boring and bushing, as well as using a taper lock.  In the end all of those options were discarded because boring the pulley would have left the remaining sleeve without enough strength to remain true even when silver soldering in a bushing.  I was afraid the cast part would crack when applying sufficient pressure to the cinch bolt to secure it to the shaft.

In the end I found the keyway on both the shaft and the pulley had worn to the point the pulley would not stay tight to the shaft.  The resolution in my case was to true the keyway in both the pulley and on the shaft, then make a custom key, both longer and wider than the standard that came with it.  I also used Loctite shaft retainer to hold the pulley tight to the shaft.

The pulley on my compressor has been tight and true for 5 years since the repair

If your shaft is worn to the point shaft retainer won't work Loctite also has a product called FixMaster for repairing wallowed out keyways and undersize shafts.


----------



## ericc (Sep 12, 2019)

I did a similar thing as one of the suggestions above with a zamak pulley.  Even with slow gentle bending, I ended up breaking it.  I put it back into service by sandwiching it between two steel plates and torquing bolts in until it was straight and stable.  It won't come apart, but you don't want to get caught in any protruding parts.  Eventually, I guess I will replace it.


----------



## Nogoingback (Sep 12, 2019)

bpimm said:


> I think it is just a standard 5/8" v belt, just 4 of them. I've only been running 1.
> 
> Kvt the only date I can find is on the tank and it's 1936




It's not relevant to your pulley question, but if your tank was manufactured in 1936, you may want to give some thought
to it's safety due to rust:









						Compressor exploded
					

A good friend sent me this picture of his step fathers 40 year old air compressor that exploded today. As far as I know he is alright after a trip to the ER for stitches. From what I gather he had not drained the tank in thirty years or so, it got to 95psi and went boom.  Probably a good...




					www.hobby-machinist.com


----------



## NortonDommi (Sep 12, 2019)

I'd check the shaft very carefully and the bore alignment.  This could be done by laying a plate across the rim and fitting a shaft to the bore, a good square and a flashlight are all that is needed,  If misaligned an easy way to fix is hire a Magdrll and get two cutters, one at nominal bore and another say 1/8" or whatever deemed suitable,(and don't discount Metrickery for getting odd sizes), larger.  Use the nominal bore size to center and clean up bore then switch to the larger size.  Drill and fit a sleeve with epoxy and cut the slit a couple of days later when the epoxy has set.  Ream and fit.  I'd work from the outer face.
  The grooves and the faces of the rim are machined at the same time so the face will be square to the grooves .


----------



## nnam (Sep 12, 2019)

I like the suggestions about checking it out first.  Check the shaft's diameter at various places and check it with an indicator to see if it's true.  Mic it to check for the diameter and compare that with the pulley.

For the pulley, I would first just check against a flat surface, simply such as your granite table (not even precision table).

If the shaft is bad, then that would need to be trued up.

If the pulley is the problem, my suggestion would be to find yourself some fire bricks and heat this up to certain temperature and prepare to true it up some how (clamp, etc.).

But ..., what if the pulley is not bent, but its center axis is not the same as that of the outside?  Maybe make a tight fit rod, insert it in and check it with a dial indicator as you rotate it?  If it's bent, maybe heat it up, weld it then drill it out with a mill or bore it with a mill and put an adapter into it (better idea)

But the experts here probably have better hand on experience and advice


----------



## kvt (Sep 12, 2019)

it seems yours seems even older than mine which means prob hard to find a good pully for it.  
I agree that to much pressure could break it,  would not try using the press on it.  
To test it you could put it on a known good shaft supported by a bearing on each end and  held some how.   Then put an indicator on it   You should be able to check both the hub area and the outer area.  This will also allow you to get a true measure of how far out it is.  and possibly what the problem  is
Just my 2 cents


----------



## bpimm (Sep 13, 2019)

kvt said:


> it seems yours seems even older than mine which means prob hard to find a good pully for it.
> I agree that to much pressure could break it,  would not try using the press on it.
> To test it you could put it on a known good shaft supported by a bearing on each end and  held some how.   Then put an indicator on it   You should be able to check both the hub area and the outer area.  This will also allow you to get a true measure of how far out it is.  and possibly what the problem  is
> Just my 2 cents



Finding a new pulley is out of the question, I found 1 that might work and it was $1300.00. 

I got some time this morning to work on it again and I cleaned the crank shaft and remeasured it, it runs true and the diameter is 1.375 +0 - .002

I laid the pulley on a flat surface and the rim is as true as my flat surface, Cast table saw top.

There was a lot of crud in the pulley hole so I cleaned it out good and remounted it on the compressor and the wobble went from .490" down to .150".

It fits nice and tight when it's clamped down but has a little play when the clamp bolt is loose, I'm thinking I will see if I can shim it to get it a little better unless that's a bad idea. I may just live with the .150".


----------



## bpimm (Sep 13, 2019)

When I put the pulley back on the compressor it seemed to require to much torque on the clamp bolt to get it to quit having play so I took it off and set it up on the mill table and ran an indicator down the hole and the side was +- .010" so I put a snap gauge in it and the hole has .009" of taper, open on the side to the compressor.

My thought is it needs to be trued up, it takes more than 100 Ft Lbs to tighten the clamp bolt enough to stabilize the pulley, using my highly calibrated hand wrenches on a movable object, lol. I can't get a torque wrench on it but it's everything I can get by hand.

How thin of a sleeve can I get away with if I bore it true then epoxy the sleeve in then rebore the sleeve to size?

Also if I do this would I bore to final size with the clamp bolt out, clamped down or somewhere in the middle?

Thanks.


----------



## matthewsx (Sep 13, 2019)

Seems like you're on the right path. Have you considered some thin lead sheet, or maybe the ubiquitous beer can shim. My inclination is still to leave the pulley as-is if you can, anything you do to fix it that's permanent might introduce other problems that are worse. Remember, as much as it might bother you to see it wobbling around if it makes compressed air it *IS* doing the job it's intended for.

John


----------



## NortonDommi (Sep 13, 2019)

At .009" I would think about some epoxy and a spiral flute reamer another way would be a smear of epoxy and clamp a bit of  Aluminium in the slot with the edge aligned so that a straight flute reamer could be used.


----------



## RobertB (Sep 13, 2019)

If you have enough shaft on the motor I would try moving the motor pulley out so your belt runs on the center 2 grooves. Having the load off to one side may have been what caused the taper to wear in the bore if it had a little play in it.


----------



## BtoVin83 (Sep 13, 2019)

.030-.060 wall top hat split bushing if you have enough wall thickness on the pulley. just bore the pulley as true as you can get it and make a top hat bushing, split it with a hacksaw making sure the gap is enough to clamp down on the shaft.


----------



## bpimm (Sep 13, 2019)

I ended up using some aluminum shim stock and have the pulley mounted tight and straighter with less torque on the clamp bolt. I now have .090" of wobble, I'm going to leave it there and watch to make sure the aluminum shims don't loosen up. Maybe I'll rebore it later if this doesn't hold.

Thanks for all the ideas.


----------



## matthewsx (Sep 13, 2019)

bpimm said:


> I ended up using some aluminum shim stock and have the pulley mounted tight and straighter with less torque on the clamp bolt. I now have .090" of wobble, I'm going to leave it there and watch to make sure the aluminum shims don't loosen up. Maybe I'll rebore it later if this doesn't hold.
> 
> Thanks for all the ideas.



The best thing about aluminum shim stock is it's always close at hand

Cheers,

John


----------



## bpimm (Sep 13, 2019)

matthewsx said:


> The best thing about aluminum shim stock is it's always close at hand
> 
> Cheers,
> 
> John


That it is...


----------



## Illinoyance (Sep 13, 2019)

Considering the mass of the pulley it is more likely the shaft was bent rather than the pulley.  Check the pulley as FOMOGO suggested.  I think you will find it reasonably true.  If the shaft is bent, remove it from the machine and build up the end (where the pulley fits) and re-machine it.  The center in the shaft will be unusable.  Set it up in the lathe so the bearing seat runs true.  Bore the center true.  Support with a tailstock center and re-machine the pulley seat.


----------



## projectnut (Sep 13, 2019)

My compressor is a 311 series built in 1965.  It's the smallest 2 stage compressor Kellogg made, and as such wasn't very popular.  Having said that I was able to find parts at E compressed Air:  https://www.ecompressedair.com/

You might want to check them out if you feel a new pulley is the way to go.  With a compressor that old I would probably use the Loctite FixMaster rather than trying to shim it..


----------



## Dabbler (Sep 13, 2019)

I'm wrestling with making a new pulley or retrofitting a completely different one for my Atlas Coppco compressor.  The pulley is broken into 5 peices (hub 3 splines and outer ring) and it is a humpty dumpty.  No way to get it back together again.  

I purchased a 'universal' plulley and am machining a custom centre hub for it.  I'll let you know how it goes.


----------



## fixit (Sep 14, 2019)

bpimm said:


> Breakage is a concern, but if it bent one way will it bend back? probably not worth the risk.
> I tried 2 belts, the motor has a 2 groove pulley but they were not a matched pair and the length difference was to much so I ran the shorter one until it gave up then ran the longer one and now it's given up. I bought a double belt to fix it but I must have measured wrong and it was to long so I tossed it aside and ran it the way it was. I'm in the process of changing the motor pulley to a larger size, should increase the compressor speed about 20%, it's only turning about 325 RPM now, the new pulley will get it up to about 400 RPM. I modified the mounting hardware so with the bigger pulley and more adjustment room the double belt should fit.
> 
> With 5HP compressors running single belts I figured that this would be ok with a single belt, it's a 5 HP motor, I don't know what the compressor head is rated for.



The speed increase will surely give you more air. Check the running amps as the pressure nears the cutoff point to be sure not to overload the motor. you should also check the compressor specs for MAX RPM. If the pump is over speed bearing lubrication & valve operation is compromised. The air discharge temperature will also be elevated & will have more water in it.


----------



## fixit (Sep 14, 2019)

bpimm said:


> Finding a new pulley is out of the question, I found 1 that might work and it was $1300.00.
> 
> I got some time this morning to work on it again and I cleaned the crank shaft and remeasured it, it runs true and the diameter is 1.375 +0 - .002
> 
> ...



ALSO, NEED INTAKE AIR FILTER


----------



## projectnut (Sep 14, 2019)

Before doing anything to increase speed find your model number and check with a Kellogg parts supplier to see what the maximum rpm of that model.  Kellogg made several models of each size with widely varying top speeds.  The 335 model for instance came in models with top speeds varying from 418 rpm to 810 rpm.


----------



## bpimm (Sep 14, 2019)

projectnut said:


> Before doing anything to increase speed find your model number and check with a Kellogg parts supplier to see what the maximum rpm of that model.  Kellogg made several models of each size with widely varying top speeds.  The 335 model for instance came in models with top speeds varying from 418 rpm to 810 rpm.


As it sits it's only running about 320 rpm, the new pulley will bump it to about 390. Don't think I'm getting to fast yet.

I haven't been able to find any specs on the compressor.


----------



## projectnut (Sep 15, 2019)

Here's a Word document with some information about Kellogg Compressors.  Mine has the size of the compressor (311) cast into the main body.


----------



## bpimm (Sep 15, 2019)

Mine is a model 33, I have found info on the 3 digit model numbers but nothing with a 2 digit number.


----------



## ELHEAD (Sep 15, 2019)

Is that a weld on the vane at the lower left?


----------



## kvt (Sep 15, 2019)

Thanks for the doc,  From that I think mine is a 352,  have not found a place with the number, but  it looks like the 352, and has the 3 groove B belt pully,   It has a 10Hp Wisconsin engine,   powering it.   
It needs valves, and I would think a new tank.  Have not use it in about 8 years,   Sits on a trailer in the back yard.


----------



## bpimm (Sep 15, 2019)

ELHEAD said:


> Is that a weld on the vane at the lower left?


I'm not seeing what you are talking about, but I havent seen any welds.


----------



## projectnut (Sep 15, 2019)

kvt said:


> Thanks for the doc,  From that I think mine is a 352,  have not found a place with the number, but  it looks like the 352, and has the 3 groove B belt pully,   It has a 10Hp Wisconsin engine,   powering it.
> It needs valves, and I would think a new tank.  Have not use it in about 8 years,   Sits on a trailer in the back yard.



The company the document in my first post came from "Air Compressor Equipment" does sell compressor overhaul kits, head rebuilding kits, and valve kits:





__





						Kellogg-American Rebuild/Tune Up Kits - Air Compressor Equipment
					

Kellogg-American Rebuild Kits - Air Compressor Equipment, Wilson, NC - Special compressors for industrial, high pressure and gas compressors



					www.aircompeq.com
				




I don't have any idea what they cost through this company.  When I needed parts for my 311 I went to E Compressed Air:








						Home | Industrial Service Solutions
					

Industrial Service Solutions − Largest and most comprehensive single-source industrial service provider in the United States and #1 choice for long ter..




					www.ecompressedair.com
				




At the time they had the best prices and delivery times.  I see some parts are still available through them, but some items like the valves have a note to "call for availability".


----------

