Crank Machine Work

Yellowhand

Yellowhand

#1
#1
I have three tapered/oversize cranks I'll be turning down to 3/4" and milling 3/16" keyways...also boring/tapping 5/16" NF threads in the end to hold clutches on...

If you have any cranks you want turned/milled/tapped, mail them to me and I'll machine them all at the same time while I have the lathe and vert mill set up to do it...

The machine work is free, but I prefer to have your crank arrive in a USPS medium size flat rate box with exactly enough cash enclosed for me to send it back through USPS...

No UPS/Fed Ex/checks/MO's/...

PM me for address...
 
Yellowhand

Yellowhand

#2
#2
This Tecumseh crank arrived last night...

The straight section is currently .770 without a keyway, so that'll turn down to .750 nicely and get a milled 3/16" keyway that is 3/32" deep...

But, there is only 1.750" of straight shaft before the taper begins, so the owner needs to decide whether to leave the tapered end on the shaft, or cut it off, re-bore and tap the new end, and run a 3/4" long spacer for a clutch...

I can make a billet retainer specifically for this shaft that has a .750" OD extension w/ keyway on it...and that's what I recommend doing.
 
george3

george3

Active Member
#3
#3
tipically the 1" part of the shaft sticks out about that much from the cover un-like the standard 3/4 style that 1" part sticks out 1/8" or so. It might not be like that on this crank but all that I have have seen were like that. Just have to get all the measurements on the standered crank and go from there.
 
Yellowhand

Yellowhand

#4
#4
george3 said:
tipically the 1" part of the shaft sticks out about that much from the cover un-like the standard 3/4 style that 1" part sticks out 1/8" or so. It might not be like that on this crank but all that I have have seen were like that. Just have to get all the measurements on the standered crank and go from there.
Click to expand...
The oil seal wear area is visible on the crank...there isn't any room to back cut into the seal area of the shaft...the .770 shaft area starts just outside the seal...this shaft isn't as long as you were hoping for.
 
Yellowhand

Yellowhand

#8
#8
...and if there isn't quite enough length to your crank after machining off the threads or taper, these retainer extensions made specifically to extend your crank to 2-5/16" really work well...

I've done them before...they're proven to work well...and now they come with a countersunk screw to perfectly align them with the shaft.
 
Yellowhand

Yellowhand

#9
#9
Three tecumseh crankshafts sent by a member...

I've just finished turning them down to 3/4", and trimming or extending them to 2-1/2"...

One already had a 5/16" tapped bore, the other two had 3/8" bores that were cut back, bored and tapped to 5/16" NF, so all three could have clutch retainers added...

They're ready to mill a keyway...
 
Yellowhand

Yellowhand

#11
#11
minibikedude said:
Hey, Those look familiar, they turned out nice! :thumbsup: You do some nice work yellowhand.:drinkup:
Click to expand...
Thanks, MBDude...I milled them today at lunchtime...turned out nice, only minor glitch was that deeper woodruff key cut on one of them...still, it'll work just fine...

Do you want to leave them at 2-1/2" long and go with some recessed retainers, or shorten them down a bit?

Standard clutch is only about 2-1/4" wide, so you've got a quarter-inch of shaft poking out...
 
KB2ROCKET

KB2ROCKET

Active Member
#13
#13
I know almost nothing about machining but through will power I turned this gx390 generator crank down to .750 and milled a key slot and shortened it and drilled and tapped the end and I can tell you it was a lot of work for me at least so please do not take yellowhands generous offer lighty
 
Yellowhand

Yellowhand

#14
#14
Man, this one showed me no love...the splines were hardened and I chipped 2 carbide cutting inserts and then smoked 2 HSS 3/16" end mills when I cut the keyway...

The shaft is only 1-3/8" long, so the clutch must be mounted with the sprocket on the outside...I didn't cut a keyway on the retainer to ensure the clutch would be mounted this way...there is no key contact with the shaft if the clutch is mounted with the sprocket to the inside.
 
Yellowhand

Yellowhand

#15
#15
5 Horse Fan said:
Well, I guess there is no way around it..... I might be sending you 3 crankshafts soon.
Should be some easy work as they only need to be drilled and tapped and 5/8" keyways.

By the way, nice work !!!!

Let me know if you want to work on mine...
Click to expand...
Don't send me any more hardened spline shafts...I can't afford the inserts and end mills it takes to machine them. Anything else is OK...
 
You must log in or register to reply here.
Top