Cutting splines, the Mighty Mickey Mouse Saga

[Wicked_S10]

I know some of you will find this of interest, so I will share some recent work. I am by no means a machinist, and every thing I try is self/internet taught. I have no idea if I do things right, or if they will work out in the end, but here is what I did.

My buddy brought me a transmission input shaft from a 60 year old Massey Harris tractor. The shaft had the splines chewed out of it in the center clutch disc end of the shaft. We welded up the damaged area, and turned it down on my lathe to the correct diameter. I then used an idea I found on another board for making a spline cutter. I made a arbor to hold a single point lathe bit in my mill. The lathe bit is a 3/8" square piece of high speed steel. We custom ground the cutter to the same shape as the spline, ground significant heel and side relief and put it in the mill. I do not have a dividing head, so this cannot be used to cut new splines, but I set up off the existing splines and used v blocks, clamps and my vise to hold the shaft in position. The first implementation of the cutter did not work well. The cutting edge should be on the center line of it's rotation, or just bellow it. I neglected to consider this and drilled my arbor wrong.

http://www.rollmeover.com/bronco_fab/odds_n_ends/odds_n_ends031.jpg

http://www.rollmeover.com/bronco_fab/odds_n_ends/odds_n_ends032.jpg

I think I also had the cutter sticking out too far from the arbor. I re-ground the cutter so the cutting edge was on the center line. Things were going much better with it until I got about 2/3s of the total depth of the spline. Then the cutter started rubbing and making a mess. With the cutting edge ground down so far into the bit, I didn't have enough room for the proper amount of relief needed and the bit started rubbing once it got into the metal a ways. The shiny end of the cutter in the next pics show how bad it was rubbing.

http://www.rollmeover.com/bronco_fab/odds_n_ends/odds_n_ends035.jpg

http://www.rollmeover.com/bronco_fab/odds_n_ends/odds_n_ends036.jpg

I decided to give up on the form cutter since I think I really need to re-design the arbor with tool hole off center so the cutting edge can be on the top of the bit w/o grinding so much of the bit away to reach center. This will allow me to grind more relief w/o compromising the strength of the cutting edge. I switched over to my original idea, which was to re-grind a old end mill into the shape of the splines, and basically make a spade type cutter and go slow and cut them in. I ground the EM to a close taper to match the splines. Put two flats on the taper 180° apart and then a light relief in the somewhat center of the flats. Put a little radius on the end and tried it out. I wasn't even sure if it would cut at all, but it did a pretty good job and made a decent spline. I had to re-grind the EM several times to get through the job, and by the time I got done I was almost out of EM, but it did a good job.

http://www.rollmeover.com/bronco_fab/odds_n_ends/odds_n_ends034.jpg

Here is the reground EM.

http://www.rollmeover.com/bronco_fab/odds_n_ends/odds_n_ends033.jpg

And this is the finished product. It is as of yet untested, we will be putting the clutch disc on soon to see what kind of fit I ended up with, but visually it looks good.

Later,
Jason

[jhama78]

necessity is the mother of invention... Looks good, best of luck getting the tractor back up and running

[foley]

Looks like it'll be good for at least another 30 years :D

[jnutter]

Very Nice!

:beer: :beer: :beer: :beer: :beer: :beer: :beer: :beer:

[Wicked_S10]

Thanks! I really wanted to make a cutter similar to the DDmachine(sp?) spline cutter with just one 60° insert, but the splines on this shaft weren't 60°. They were less than 60°, but I don't think that they were 45° either, which seem from my research to be the most common spline angles. Somewhere in the middle, and I am going to try to measure the exact angle, and go through my tooling catalogs to see if there are any matchin inserts. This 10 spline input shaft is a pretty common spline type for power transfer, so it would be a useful tool in the arsenal.

BTW, nutter, you'll appreciate this, GORTONS RULE!

Later,
Jason

[Wicked_S10]

Well, I found a 10 spline clutch disc in my parts pile, and tried to fit it on the shaft, and it was a no go. Looked like the EM cut splines were just a hair off on angle. I decided to give the form cutter another go. Third try was the charm on that devil. I read a lot about grinding your own bits the other night. One suggestion was to set your grinder rest at 7° and use it to cut all of the relieved sides. I cut the shape with 7° of relief, and then I used the rest set at 0° and cut the top edge of the bit down bellow the center of the arbor. I read that form cutters do not need any top rake, but I ground a bit just to be safe. I really wish that I had figured it out in the first place, it definitely went faster than cutting with my EM. Anyhow, here are the pictures.

http://www.rollmeover.com/bronco_fab/odds_n_ends/odds_n_ends037.jpg

http://www.rollmeover.com/bronco_fab/odds_n_ends/odds_n_ends038.jpg

http://www.rollmeover.com/bronco_fab/odds_n_ends/odds_n_ends039.jpg

And a picture of the touched up splines.

http://www.rollmeover.com/bronco_fab/odds_n_ends/odds_n_ends040.jpg

Proof is in the puddin'. The clutch disc fits, I can't feel any difference in fit between the existing and newly cut splines. It is tight, with very little play. It should do the job nicely.

http://www.rollmeover.com/bronco_fab/odds_n_ends/odds_n_ends041.jpg

Later,
Jason

[PTSchram]

Nice work! I'm sure it will last another 30 years.

You're a better man than I with the patience to make that cutting tool. I can barely stand to grind my own and admitted to taking a second semester class in grinding just to learn how to do it right. I still hate to have to grind them, but sometimes, it's easier and cheaper than using welded inserts.