Dilemma-- PTO end of crank

randallc · #1 02-16-2014, 06:52 PM

Deep into the process of rebuilding my 1250 with K301. Bought a used crankshaft, good fit, EXCEPT: Starting to put my PTO clutch back on and it is does not have the threaded whole in the end of the crank. It apparently came from a Cadet that used the set bolt to make contact with the Key.
Question: Can the Crank end be drilled and tapped while in the engine, or can I use one of the clamp on PTO clutches on the 1250? Or, does it all have to come back apart??

mortten · #2 02-16-2014, 07:45 PM

Here is a vid of a guy drilling a crank in the engine:http://m.youtube.com/watch?v=fO1JUnP7ZTo

randallc · #3 02-16-2014, 09:25 PM

thanks for the video. Maybe should talk to the machinist who. bored the engine to see if he can tackle it. He might have a something like that.

sawdustdad · #4 02-16-2014, 09:34 PM

The machine shop should have no trouble drilling and tapping the end of the crankshaft for you.

dvogtvpe · #5 02-17-2014, 09:15 AM

actually if you own a drill and a tap and die set it isn't that hard if you can drill a straight hole. the cranks are cast iron so its easy to work with. you might want to measure the length. I thought there was a slight difference in length on the pto end. but I could be wrong. been a while

782CC · #6 02-17-2014, 10:22 AM

Quote:

Originally Posted by dvogtvpe

actually if you own a drill and a tap and die set it isn't that hard if you can drill a straight hole. the cranks are cast iron so its easy to work with. you might want to measure the length. I thought there was a slight difference in length on the pto end. but I could be wrong. been a while

Agreed. And drilling a straight hole is easier than you think. Where the vid can improve is you spin the part not the drill. The drill will center to the spinning object. The engine running is way fast but could be managed if cautious about the heat and plenty of cutting oil. And if the stars align, a drill running as well could bring drill RPM to crank down to what you need. The idea is futile if the engine running is the wrong way for the drill bit.

Sam Mac · #7 02-17-2014, 11:08 AM

I would think you could put the engine in a drill press and drill it with out too much trouble. If the drill press has a table that pivots with some slots in it you could probably bolt the base of the engine to it.

782CC · #8 02-17-2014, 11:48 AM

That could work to if the drill press can hold it. Mine harbor freight version to lightweight.

OP - The crank should be easy to drill. So don't frett that. And the hole center is actually not that critical. The job is to hold the washer in place that holds the clutch on. As long as it does that it will be fine. Being off would really only affect the balance of the engine. And minimal at that. (I have done this with a hand drill btw)

randallc · #9 02-17-2014, 07:36 PM

Thanks for the info and I will measure it to be sure. Have a drill press, but a good way to get it there, its in a different shed. Tried to line up my drill press vice with the end of the crank using wood cribbing. Wood moves, may just go at it with hand held tomorrow.
Thanks for the info. If I mess up too bad, just another costly mistake. But, always love trying stuff for the first time. Failure ain't bad, just disappointing.

sawdustdad · #10 02-17-2014, 08:55 PM

Just make a drill guide to keep the hole straight.

Take a wood block, like a piece of 2x4, say, 6 inches long. Stand it on edge and drill a 1 inch hole half way through (1.75 inches deep). Change bits to a 3/8 and continue drilling through, keeping the bit centered. Now, take that block of wood to the crank, slide the 1 inch hole over the shaft, and drill the correct size hole in the crank using the 3/8 hole as a guide. I think the bolt is 7/16? Adjust the 3/8 hole to the correct size for the drill that matches the tap being used.

Again, the hole concentricity and parallelism is not critical, the bolt and washer just hold the PTO on. This wood guide will get you plenty close.

there's a reason I go by "sawdustdad."