View Full Version : How to make splined shafts?

02-12-2008, 04:44 PM
I first posted this on the 3rd hand forum, but didn't get a lot of response, so I'll try here as well:

My neighbor is developing product to sell, and needs to have some stock material machined. He's done his prototyping and is now looking to do production runs on a modest scale. These are splined rods made of hard brass. Around 5/16" diameter, both triangular and modified square splines. The center hole is optional, but would be nice. He's thinking of stock lengths of maybe 6", which he would then cut into smaller sections as necessary. Or it might be better parted off to final length. What kind of machine would be best suited to making these economically? It seems like just the thing for a guy with a few machines in his garage and a small side business. If he could could deal with someone locally (Portland Oregon) that would be nice, but it would be easy to ship small parts like this anywhere. Any ideas on where to direct him? TIA.


02-12-2008, 05:15 PM
For square or triangular splines, just mount the shaft on a dividing head, and use a cutter on the mill. There are several pages showing the three cuts necessary to do the square sided spline in Machinery's Handbook.

For the triangular spline, use a 60 double-angle cutter and you can do the cut in one pass.

Good luck,


Steve Steven
02-12-2008, 09:25 PM
Don't most of the gear companies (SPI, Morse, Stock Drive, Boston, ect) sell stock like that? At least with gear shape to the splines.

02-13-2008, 01:28 AM
it depend on how many feet you want of that. A screw machine could roll that spline and drill it in most any length within reason and part it off. tooling that machine would cost a small fortune but after that you could buy that part by the mile. I bet 6" peices could be made in 1 minute or less.

now if you want a 6 inch peice of each you will pay a small fortune.. :D

If I had to quote that job I say $20.00- $25.00 an inch. buy it by the mile and be down to $20.00-$25.00 a foot.

02-13-2008, 02:16 AM
Any 4 axis CNC can knock these out.

They must have a back support/clamp to prevent deflection.
Nobody is going to touch a .117" hole 6" deep, with any tolerance. (Scaled from the screen.)
Reasonable tolerances.
Moderate quantities.
Upfront tooling costs are significant, depending on the exact geometry.
The sharp points of the star shape are not really sharp.

If you only need a few, tattoomike is far cheaper than I would quote. (And, I'm retired, home shop, with no overhead.)

02-13-2008, 02:37 AM
good to know you dont work cheap mechanicalmagic. I would not call that a gravy job..

02-13-2008, 11:08 AM
I did it like this, and it worked:


Sorry for the boring monotone, but I got asked a lot of questions about how to build my gokart, so I did videos to answer them.


02-13-2008, 12:31 PM
Mark,Just so you know you used Socket Head Cap Screws for the bearing housing, NOT Hex Head Cap Screws.

This may confuse folks who don't know any better. :)


02-13-2008, 08:31 PM
Sure looks like an extrusion job to me but it wouldn't be brass. Look at this Co's work. http://www.profileprecisionextrusions.com/shop/productgallery.htm

If it can't be aluminum or plastic, at least you can see how to dimension and tolerance the the drawing so someone can see what to bid.

02-13-2008, 08:39 PM
Here's how I make mine;)


02-14-2008, 06:30 PM
extrusion ? but a couple of grand for the tool, and watch the tollerance on twist, extruders can be a bit tricky by quoting by the meter not the length

02-15-2008, 02:15 PM
Mark,Just so you know you used Socket Head Cap Screws for the bearing housing, NOT Hex Head Cap Screws.

This may confuse folks who don't know any better. :)

Thanks, Jay. Apparently, I didn't know any better. Of all the people who have seen that video, you're the first to bring that to my attention. :D


02-15-2008, 02:21 PM
Seriously, though - making splined shafts to make up to golf cart motors doesn't seem that hard to me. Making the mate to such a shaft seems hard to me.

I'm thinking of the splined "sockets" that the shafts I've made need to couple to. What's the best way to do that (aside from casting)? A shaper? A big honkin' broach? In the case of a golf cart motor, the splined hole I'm talking about is not clean-through. There's some material "mashing" in the bottom of the hole, suggesting some kind of punching operation.

So what's the deal? Sorry if this is a rookie question with a simple obvious answer, and thanks in advance.


Spin Doctor
02-15-2008, 06:47 PM
Internal splines can be made either by the use of a shaper (vertical or horizontal), a gear shaper or by means of a rotary broach. IMO the second option produces the best results. When using a gear shaper for internal work in a blind hole a relief groove is required on the bottom of the bore. It also the only way to produce solid double gear shaft (two gears on one shaft having different Pitch Diameters) where one gear is seperated from the other by a narrow groove.

03-19-2008, 03:38 PM
This video (http://www.slatertools.com/video.htm) shows some spline / serration rotary broaching.