More shaper fun! Making internal splines.

[Technical Ted]

The longer I have it, the more I love my little Rhodes shaper! What a handy machine to have in the shop. I needed to make two internal spline hubs for a fellow machinist I know that's an odd size. Both he and I searched, but couldn't find generic hubs for a 1-3/8" OD x 10 involute spline shaft that matched up to what he needed. I had some leads on a couple of "spline" specialty houses, but even they didn't have something that would work, although they would make some to fit. So, here we go for some fun!

I needed to grind a proper tool so I drew the spline profile up in Fusion 360 and 3D printed ring gages until I came up with a very good fit. I then cut out a section of the ring gage to use for a gage for grinding the tool. Starting on the Cincinnati tool and cutter grinder I started the profile and finished it up by hand on my bench grinder.



The tool looks bigger in the picture than the gage piece, but it must be just because it's up higher closer to the camera, because it fits nicely.



For something like this that is basically trial and error to fit, I don't like using a dividing head for a few reasons. First, you can't see what's going on while cutting. I like to be able to watch the tool in action to judge depth of cut (or allow a couple of spring passes) and also have an easy path for applying cutting oil. Also, once in the dividing head chuck the piece must remain there for the entire operation. I like being able to remove the workpiece for trial fitting and inspection to determine any adjustments I must make. So, I drill/ream the required divisions on a short section of additional length for an indexing pin. Works great!



I made up a nice, solid bar holder a while back replacing the clapper for operations like this. Much more solid setup. Form tools can build up some forces on this little 7 inch machines. But, after what seemed like a thousand strokes, the two spine hubs were done. Only had to machine off the short section of extra length with the indexing holes. Fit like a glove!




Man, I love this little machine! Fun project with a little CAD, 3D printing, lathe, mill and shaper work.
Ted

 

[addertooth]

Sure beats doing it by using a Lathe as a manual shaper. I did that on a key slot, and it was more labor intensive than I thought it would be.

 

[Technical Ted]

Sure beats doing it by using a Lathe as a manual shaper. I did that on a key slot, and it was more labor intensive than I thought it would be.

Haha.... one of my very first jobs as a machinist was dragging in blind keyways on a Monarch lathe. Drilled a hole at the start of the blind to give a place for the tool to be fed in and dragged them going out. This is what the drawing called for. A job only suitable for the newbie in the shop!

Ted

 

[jcp]

Outstanding indexer!!

 

[NCjeeper]

Nice work!

 

[C-Bag]

Outstanding indexer!!

I wouldn‘t have ever thought of that, thanks Ted.

As much as some bag on the small shapers I love mine and it’s come in super handy. Wouldn’t get rid it for anything.

 

[Technical Ted]

I wouldn‘t have ever thought of that, thanks Ted.

As much as some bag on the small shapers I love mine and it’s come in super handy. Wouldn’t get rid it for anything.

I made the piece 3/8" longer than required and bored just a touch bigger than the spline OD. Once the vise was tightened I removed the pin for bar clearance and oil brush access. I would have been working in the blind if using my small dividing head and it wouldn't have been easy getting cutting oil in there. And it sure is nice to be able to completely remove the workpiece for trial fitting. My preferred method for internal work like this.

Ted

 

[C-Bag]

I needed to grind a proper tool so I drew the spline profile up in Fusion 360 and 3D printed ring gages until I came up with a very good fit. I then cut out a section of the ring gage to use for a gage for grinding the tool. Starting on the Cincinnati tool and cutter grinder I started the profile and finished it up by hand on my bench grinder.

So instead of 360, 3D printer etc could the profile be done with a comparator?

 

[Technical Ted]

So instead of 360, 3D printer etc could the profile be done with a comparator?

I've only used a comparator a couple of times years ago, but I don't see how you could get a good shot of the splined profile on the shaft since the body in the center is a larger diameter than the OD of the spline and you would have to shoot it looking straight down the barrel so to speak... The tool wouldn't be a problem, but without the spline image there would be nothing to compare it to.

Having a gage to grind the tool was truly the secret to how well these couplings turned out. I made an internal spline before I had my 3D printer and tried grinding the tool just by eye comparing it to the male spline. I was not happy with how that one turned out. But, I'm very happy with how these two turned out. The gage was the recipe for me.

Any method you can come up with to form a gage would work. Clay, wax, dip tool protective, anything that would take the form and retain it would work. Or, maybe some can even grind it without an aid and it will turn out fine.... didn't for me, but I'm sure there are others out there that can do better than I did in my attempt.

I searched for images of involute gear teeth profiles and they didn't seem to match up with this profile. The generators for Fusion 360 didn't work at all for this. Maybe they do for some splines, but I couldn't find one that matched this one. It's a coarse tooth pattern for the diameter.

Anyways, there may be other, and better, ways to do it, but this worked out very well for me!

Ted

 

[C-Bag]

Yup, we have the tools that work for us. I don’t have 360 and honestly don’t have the time to invest from scratch. Your ring gauge was the secret. And I agree the problem is to generate that. I don’t have a 3d printer either but what popped into my head was using some JB WELD Steel stick epoxy putty years ago. I could see taking a batch and mixing it up then squeezing it into a couple of splines that had like Fluid film on it so it wouldn’t stick and let it set up. Then slicing it like you did with your gauge. Then it’s the tool grinder then the bench grinder. There’s the smallest comparator, ‘42 Jones & Lampson, locally on CL and he wants $300 and if he ever gets below $200 I’m a gonner and going to have to go get it.