small engine crank straightening

[D.J.]

So has anybody seen one or built one? I assume one could be made out of about three roller bearings on adjustable bolts on a spindle?
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CASCADE SHADE ZERG

 

[lilredex]

Are you talking vertical shaft lawnmower? Yes?.................my solution was a wooden block and BFH. Still running fine.................

 

[Torque1st]

Wood blocks and a hydraulic press. You should really regrind the crank after straightening but for home shop repairs you can sometimes skip it.

Why would you want to use roller bearings?

 

[D.J.]

I wouldn't necessarly but I don't suppose I have ever really seen the actual straightener machine that is used for the process. I thought their would be a machine for straightening process. Touque First I guess I understand what you are talking about.
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RED HEAD LIVE

 

[Torque1st]

I have seen it done many times for crankshafts out of small engines up to large 8' long diesel cranks. There is no automated machine that I know of. The operator was very skilled. He also straightened hydraulic rams and ran the welding machine to weld up crank journals.

For a while I worked as a crankshaft grinder in a re-builder's shop.

 

[kbs2244]

I have never bothered.
Many people treat them as throwaway engines so you can pick up parts engines at the curb all the time.

 

[FNFS2000]

Are they really worth the time? If you insist on fixing the mower, buy a new crank. Most working mans time is worth more than the cost of a mower, unless of course that time is spent teaching your son how to work on an engine, then its priceless...

 

[semi42]

have got one of these at work easy to use and it looks fairly easy to make one if you have the fabricating skills

http://www.centralspares.co.uk/index.php/product/1113/catalog//section//search/true

 

[CasualObserver]

A friend of mine had this one for sale a while back. I could see if he still has it if you're interested.

 

[rustyjeeps]

Giggity

 

[D.J.]

CausualObserver, If you don't care find out what he would want for it shipped to 62867.
Thanks for your help I had always heard of them but had never seen one before your post. Thanks again D.J.
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ZX14 VS HAYABUSA

 

[CasualObserver]

D.J., I've asked him about it, and directed him over here to the forum/thread.

 

[D.J.]

So is it for sale? Did you find out anything about it?

 

[Packard V8]

I've got one which will straighten up to a Cummins 6-cyl crank. Shipping would be a bit much, but if you want to go into the business, there is always a demand for someone who knows how.

jack vines

 

[tdkkart]

Hmmm, made about 15 miles east of me......cool.
Googled Little Brute, apparently at one time they made a bounch of small engine stuff, trademark was registered in 1966. No idea if they are still there.


BTW, those cranks are pretty soft, a pipe or a block of wood and a BFH usually gets them pretty close. Last one I did was a horizontal 5hp on a chipper/shredder, guy ran his pruning shears through the shredder chamber.........

 

[shanker]

so If I have a Honda Mower with a bent shaft...can someone explain to me the best way to straighten the shaft with a block of wood and a BFH?

 

[5lima30]

I had a push mower that I bent the shaft when I hit a metal culvert pipe. I straightened it with a BFH. It did have a small vibration but lasted 6 years before it died. YMMV.

 

[BADSIX]

take the blade off and rotate the shaft to find the hi spot, mark it with some chalk. then with a block of wood on the hi spot hit it with the bfh. it doesn't take much the crank end is fairly malible. if you can fix a piece of wire to something to use as a pointer you should be able to get it real close. sharpen the blade and reinstall and your ready to mow

 

[bgott]

if you can fix a piece of wire to something to use as a pointer you should be able to get it real close.

What, and waste an excuse to take a trip to HF?


http://www.harborfreight.com/catalogsearch/result?q=dial+indicator

 

[Gregg33]

My memory is fuzzy on this but I recall my dad straightening one by hand (forget how), then putting it in a drill press to see how true it was. Don't remember it being that big of an ordeal.

 

[lilredex]

so If I have a Honda Mower with a bent shaft...can someone explain to me the best way to straighten the shaft with a block of wood and a BFH?

Just as badsix describes...............did it with one blow. Just as good as new to this day. Figured I had nothing to lose by trying, and it proved to be true. Mine is a Tecumseh.

 

[W650Mike]

I spent several high school summers cranking on one of those “Little Brute” straigtheners. I think we charged $16 (in 1977) plus a new flywheel key and labor. (Whenever an obstacle bends the crank, the shear key is always sheared.) The press broke the case about 1 in 5 tries if the crank was really bent; hardly ever if the crank was only slightly bent. Not shown in the pic is the sleeve that slips over the end of the crank.

One mean old lady started taking her bent crank problem out on me. I'm ratcheting on this press in 105º heat. Her case broke.

 

[Milton Shaw]

I did them when I was a teenager in the 60's same machine. You usually had to change the flywheel shaft key if it was a Briggs Engine they would be stripped and make it hard to start. Easy to get it nearly perfect, and mower would cut the grass a lot smoother. My dad was always bending his.-- The thought if you could get it under the machine it ought to cut it. -pipes, rocks, glass, shoes you name it.