steam engine crankshaft machining

[dbasberg]

<font face="Verdana, Arial" size="2">Originally posted by Oso:
I like Al's idea. Works well, seen it used on QC box shafts.

If you use a pin instead of a screw, you have some chance of replacing the shaft if you ever have to, though. The threads look about impossible to duplicate.</font>

I thank you and Al for these ideas on locking flywheels to crankshafts. I heard the designer of my steam engine later changed from the keyway/set screw arrangement with a taper pin locking method (similar to your suggestion). He suggested that the flywheels were working loose on the key and the taper pin worked better.

[dbasberg]

I got some time in the shop today. The water hardening drill rod filed easily, so I cranked the mill up to 1600 rpm and did a 1/8 hss 2 flute mill by 0.025 deep and it cut like butter. The second cut was another 0.025 on slow power feed, again excellant! The third cut finished the total depth of .0635" that I wanted. The keyway mic'd to 0.1255" wide and was quite straight. I'm a happy guy. I intend to harden the area around the keyways for more resistance to damage. Now I am machining the crank disc from the cast iron casting. Then I will be broaching the keyway in that...we are on our way. This BBS is great. The great people who responded to help with my problem sure gave me good advise. I am very greatful.

[Al Messer]

WARNING! THIS IS RANK HERESY!

You could "glue it together" with Loc-Tite. Even with 3/16" keyways in the axles of the drive wheels on my locomotive, I'm using Loc-Tite, but please, don't tell Thrud!!LOL

[dbasberg]

<font face="Verdana, Arial" size="2">Originally posted by Al Messer:
WARNING! THIS IS RANK HERESY!

You could "glue it together" with Loc-Tite. Even with 3/16" keyways in the axles of the drive wheels on my locomotive, I'm using Loc-Tite, but please, don't tell Thrud!!LOL</font>

Loctite 609 goes into most press fit joints I make, but I had not thought of this application. Hmmm...sounds good
I was going to make a mandrel to press the crank disc on for turning the outside edge and that needed to be turned down from 3/4 stock. You have reminded me that a little 609 on a 5/8 shaft might be adequate for hold, then I can arbor press it off. What do you think? Is that a viable approach? (save a lot of chips)!

[Thrud]

Al, Al, Al,
I ran out of firewood so we can't burn you at the stake this time. Actually it is a common trick in the UK.

Kap
A smart man marries a smart woman with her own tools - you is sneaky!