Cast Pulley Repair

Tomc938

Tomc938

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In the disassembly of a step pulley from the new/old drill press I recently got, I dropped the pulley as I was coaxing it off the shaft. #&D^#%@!!

Any suggestions on how to repair?

There is plenty of room for a patch. I was thinking of turning a piece of steel to the OD, drilling and tapping a number of smaller holes to bolt the plate on, and the install a couple of bolts in the small piece. As the piece will be in compression when the belt applies pressure, the bolt in the piece are more to hold it in alignment than hold against the force of the belt.

Probably add Plastic Steel just because I bought large tubes of it from Princess auto.

Do you think I'm on the right track?

Thanks! IMG_9892.JPG
 
whydontu

whydontu

I Tried, It Broke
Premium Member
Clamp together, drill through for a roll pin into broken part and into hub, smear on some j b weld. Let it cure, file to fit. Since the hub is still solid, the web won’t be under much load.
 

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Susquatch

Susquatch

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Another crazy idea.....

Do you have room for a thicker end? If so, you could epoxy the piece back on and then glue a cap plate on and then drill and tap the plate with three Cone screws to make it permanent.

If not shave some off of the big end and do it anyway.
 
Proxule

Proxule

Ultra Member
Access to heat and low fuming bronze rod?
Could probably go to the local welding supply and barter or beg for 3-4 sticks worth and have it brazed up in less then 30 minutes ( heat up cool down time will be the majority of it )

Gluck
 
F

fixerup

Super User
I think you are on the right track, but since you bought a large tube of plastic metal, I would skip the bolts part. Instead I would rely on the available large glue surface of the pulley face and the outer lip edge of the cup washer to keep things together.
I would clean the pulley very well. then glue the broken piece on a flat surface using a hose clamp to keep it together and then let it cure. Meanwhile I would scrounge my scrap bins for some plate material about 3/8" thick . Then roughly cut the o.d round, 1/2" larger than the o.d of the pulley. Mount the plate in the lathe chuck and drill 1/4" hole through, then bore an inside cup .050" larger than the O.D of the pulley and deep enough to match the thickness of the pulley edge about 3/16" deep. Smear glue on both face, put them together, trying to center the cup to leave a .025" bead of glue all around the edge of the pulley, let it cure very well . I would mount the pulley in the lathe chuck and turn the cup washer o.d, the face thickness and bore hole to size.

Note: when machining parts held together with glue or double sided tape , it always a good idea to monitor the heat generated after a cut or else the bond could come apart. Double sided tape is worse, it doesn't take much heat, for the assembly to come apart, but I have used it successfully many times.
 
Susquatch

Susquatch

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140mower said:
I would look at the other options in the order of not screwing you out of the next plan. It's always nice to have two or three different options to follow in a descending order until you are down to the "Hail Mary pass" at the end. :rolleyes:
Click to expand...

I love this advice. I'm gunna write that down someplace and pass it on.

Been there and done that many times. Also done it in the wrong order and regretted it.
 
Susquatch

Susquatch

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Brazing is like welding. It's a great plan as long as you are good at it. Me? I suck. So my first choice is usually what I can do well.

What I don't like about brazing is that I'd have no backup plans.

If I could braze well and had done it many times, I might feel differently.

@Tomc938 - looks like it's just an ear of the pulley that broke. If so, it might even work without the ear, but the belt will get chewed up and won't last.

I'm still thinking epoxy and an add-on flange support - think big thick washer glued and screwed to the outside.
 
F

Former Member

Guest
Tomc938 said:
In the disassembly of a step pulley from the new/old drill press I recently got, I dropped the pulley as I was coaxing it off the shaft. #&D^#%@!!

Any suggestions on how to repair?

There is plenty of room for a patch. I was thinking of turning a piece of steel to the OD, drilling and tapping a number of smaller holes to bolt the plate on, and the install a couple of bolts in the small piece. As the piece will be in compression when the belt applies pressure, the bolt in the piece are more to hold it in alignment than hold against the force of the belt.

Probably add Plastic Steel just because I bought large tubes of it from Princess auto.

Do you think I'm on the right track?

Thanks!View attachment 39681
Click to expand...
Been there (with my first drill press I got free), source a pulley (PA?), turn the inside on you lathe and fit to Drill press, good as new.

No heat, no fumes, no sticky mess, and at least you still have the original to fall back on if it doesn't (with one less speed).
 
M

Mcgyver

Ultra Member
Braze or turn it off, press on (or loctite, even easier), a sleeve and re-turn the V slot. Make the sleeve first, set the pulley up on the four jaw, indicate it dead on and turn it all at that setting. Not crazy about epoxy etc, its subject to centrifugal force. While the barista class loves to adorn their faces with bolts and pins and hunks of metal, it's embedment in my forehead wouldn't with my look
 
Tomc938

Tomc938

Ultra Member
Premium Member
Lots of good advice.

I'm leaning toward Susquatch's initial advice, with a slight modification that takes in Mcgyver's caution. (The inner kid in me assumes when cobbling something together "Mcgyver" has the best advice)

My first attempt will be to take a plate of 3/8" steel and turn it to larger that the outer diameter of the pulley. I'll clean up one face, and then turn a recess on the other side so the pulley diameter goes into the recess. Use the three Cone screws into the meat of the hub. Use plastic steel to hold everything together and put a couple of small (M3 or M5) bolts into the small part to take the lateral forces.

If that fails, I do know a retired welder from the pulp mill who could braze it up real pretty. But I would rather be independent, and have a fallback plan as 140Mower so wisely suggests.

Plan C would be to turn the whole mess off and Loctite (Glad I noticed before posting - auto correct changed Loctite to lactate) another chunk of metal and turn the pulley profile.

Plan D would be to get another pulley from Princess Auto.

Plan E would be breaking the whole thing into pieces and see if my furnace will melt cast iron. ;o)


I think Susquatch is also right that the pulley woudl work just fine without the part, but belts would become a consumable.

It's gonna be a while until I actually get to this, but at least now I have a plan.

Here's a picture of what I plan to do. (not to scale)

IMG_9897.JPG ​

 
M

mbond

Well-Known Member
Premium Member
Estimating the size of the part from the picture, and considering the exposed grain and other machining marks, I think you really have to braze it back together or turn it off and replace the flange. The other solutions seem fragile and I would not attempt to tap that metal

Alternately, you could just not use that part of the pully. Adjusting the feed rate can accommodate reduced control of the spindle rate
 
Tomc938

Tomc938

Ultra Member
Premium Member
mbond said:
Alternately, you could just not use that part of the pully. Adjusting the feed rate can accommodate reduced control of the spindle rate
Click to expand...
Well, that's something pretty obvious once you say it, it just didn't occur to me!
 
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