Making new rear hub, correct taper

[Reno Speedster]

I am making some new hubs for my Dayton wheels. I have been reading the old posts on the wire discussing the correct taper and there does not appear to be consensus. The original drawing I saw says the axles use a 1-1/2 inch per foot taper. This works out to a 7.15 included angle. I can cut the taper on the lathe, but you always get some flex on the boring bar and it is hard to get a really smooth finish. I can purchase a 1-1/2 inch per foot reamer to finish things.

The question is, is the 1-1/2 inch taper per foot the correct taper? The steel (some big chunks of 4130) is pricy and I want to be sure of the plan before I start cutting. If push comes to shove, I can make one out of something cheaper, but it would be good to know if this is the correct taper before I order a reamer.

[got10carz]

Just chuck up a known good axle in the lathe and indicate the taper in.

[Reno Speedster]

Yep, but the reamer would make a better finish. Also, I would need to cut the axle off (it’s too long to go between centers) to fit it in the same way as the hub taper.

[Kevin Pharis]

Indicate the taper along the back side…

[Reno Speedster]

How would that help?

[Kevin Pharis]

Setting up the taper gage with the back side of the axle taper will be in the same direction as you would cut the hub

[Reno Speedster]

Is that for setting a taper attachment? If it is, I don’t have one. I cut tapers with the compound rest.

[Dan McEachern]

Just FYI, You really don't need 4140 for hubs. 1117 or 12l15 would machine much easier and still be plenty strong.

[Reno Speedster]

Thanks, I am using 4130, not 4140. I got a good deal on it and it should do fine.

[RecklessKelly]

Cut the taper on a scrap piece of aluminum and blue it up. Press into the mating part and see if the witness matches.

[Jerry VanOoteghem]

Yep, but the reamer would make a better finish. Also, I would need to cut the axle off (it’s too long to go between centers) to fit it in the same way as the hub taper.

The axle won't fit through your spindle?

[Reno Speedster]

Yes, the axle will fit through the spindle. But, if I set the angle of the compound rest to the taper with the axle sticking through the spindle, the minor diameter of the taper will be furthest from the chuck. If I did it this way, I would have to chuck the hub with the flange held by the chuck and the center sticking out. If I did this, I would have to reach through the small end of the taper to cut the large end of the taper. While this might be possible, it would be a pain.

If I turn the axle around and put the major diameter of the taper furthest from the chuck, I can grab the center of the hub blank in the four jaw and cut the matching angle. This gives me good clearance for the boring bar (since the taper opening will get larger as I cut it) and I could use a reamer to finish. The only issue is that my lathe bed is not quite long enough to hold the entire axle between centers. The plan is to cut about a foot (including the taper) off of a new axle so I can run the stub between centers and set the angle. Once the taper is cut, I will mount the hub blank on the axle stub and grab the axle stub in the lathe (either in the 4 jaw with pads or in a collet) and support the nose with a live center. That way, the hub would be turned off of the axle and would be concentric to the taper. There might be another way to do it but, with the tools I have, I think this is the best way.

Having said all that, I am still looking for information on the proper taper angle for the hub.

[Reno Speedster]

Cut the taper on a scrap piece of aluminum and blue it up. Press into the mating part and see if the witness matches.

That is a good plan.

[RecklessKelly]

Another way: If you blue the shaft and scribe two lines on the taper one inch apart in the X direction by dial indicator on the lathe carriage, indicate the taper depth from line to line in the Y, and now you can trig the angle. Set the compound by the grads as a rough start, they arent very accurate, and then cut a blank rod with that taper. Blue, scribe and measure the same way to verify the compound against your calculated angle. You may have to recut the scrap and tap lightly on the compound angle to fine tune it. Keep your tool post and bar snug to the work to reduce vibration. Compounds arent that beefy and the feed is rough by hand unless you have a beefy lathe.

[AndyClary]

Morgan, like Kevin pointed out above, if you indicate on the back side of the taper your compound will be clocked properly to bore your taper. I can set it up and send you a picture if you want.

Andy

[Reno Speedster]

I would like to see that.

[Reno Speedster]

Eureka!! Now I understand about zeroing in on the back side! Took me a bit (and some explaining from Scott Conger) to think it through. I have cut tapers before, but this is the first time I have used a male taper to cut a female matching taper. It’s fun to learn something new, especially something that makes things simpler.