Window crank extension available?

[Jeff Berk]

I need to extend the crank shaft maybe 1/2 inch to keep it from rubbing against the door card covering. I had covered the door in leather and added 1/4-inch or more of foam and quilted the leather. I've found some extensions for Ford, Chevy (picture attached) and a few other cars but I was told by the vendor that it will not fit the Datsun Z.

Before I try and machine a couple, does anyone know a source for this item. If not, anyone have a detailed, scale drawing of the shaft I can use as a starting point if I have to create one?

[zKars]

Well the datsun spline is 10.7 mm OD and also has 16 splines, so maybe just start with a Chevy adapter and turn the splined part down to 10.7mm, deepen the splines and Bob’s your uncle. 

the OD of the non-splined part below the Datsun splines is 12mm. Darn close to 1/2”, so that adapter might just slip right over and work once you “adjust” the splines a bit.

Or put Chevy crank handles on the Chevy splines and be done! Who’s going to notice! (Sorry had to add that)

Edited June 13, 2023 by zKars

[Jeff Berk]

My understanding is the spline part and set-screw tube are welded together. As long as the two parts are precisely aligned, I might be able to turn it down on a lathe from 11.18 mm to 10.7 mm.

Edited June 13, 2023 by Jeff Berk

[Patcon]

Did you ever figure this out?

 

[Jeff Berk]

I decided to try and make a pair of them. I just received the mill bits yesterday from China and will try to mill the extensions next week. I figured if I tried to turn down the 11.18mm to 10.7mm, the splines would not be deep enough.

CrankExtension.pdf

[Patcon]

I may need a pair too because I am looking at doing a similar door panel finish

[Jeff Berk]

I'll let you know if it works. I hope you are in no rush. 

[Patcon]

At the pace I work!? I think you'll be fine... 😉

[Yarb]

Three is the lucky number! Count me in as well friend.

[Jeff Berk]

I made a set but they extended the crank out too far so I'm trying again. I think I can get it down to just over a 1/2 inch extension. These are hand milled so they take maybe an hour to create. I will likely become more efficient by the time I make 3 pair but please, no more requests.

[Captain Obvious]

On 7/13/2023 at 5:44 PM, Jeff Berk said:

I figured if I tried to turn down the 11.18mm to 10.7mm, the splines would not be deep enough.

The difference between those is only 20 thousandths. You really think that would be enough to make it not work? Did you buy some of the GM adapters to poke around with? I'm thinking there's got to be a relatively easy way to come up with something.

Do you have a pic of the part you made?

Neat project. Seems like the kind of non-profitable work I would get hooked into! 

[Jeff Berk]

The following information us based on the orientation in the photograph:

The one on the right is an early version. I realized the spline could be shorter and the hollow part on the bottom needed to be longer to accommodate two horizontal cuts (not performed yet) to fit a wire crank clip that attaches the adapter to the spline shaft on the door. A second crank clip attaches the window crank to the adapter. 

I decided that the long neck on the one on the right was not needed and extended the crank handle shaft too far.

You are correct my Captain, a non-profitable job but an opportunity to get more proficient at using the lathe and mill along with learning how to use the indexed clamp to cut 16 splines, 22.5 degrees between each. 

Edited July 26, 2023 by Jeff Berk