My Century 10A Restoration

[Harold_4074]

I just rechecked the tilt screw on my stand (a 1A Semi-Centennial from the "Eastman Kodak, Folmer and Schwing Dept." era) and it is half inch diameter, 1/20 inch pitch, with five starts for an actual lead of 1/4 inch per turn.

Interestingly, the central part of the screw is worn enough that two turns from either end give a slightly different measurement than two turns in the middle. As the nut moves from the unworn area, it "advances" by the amount of wear in addition to the actual lead of the screw.

A spot-check of availability (McMaster-Carr online catalog) shows Acme 1/2"-8 two-start rod at $49.02 for six feet (#99030A716) and the matching nut for $23.53 (#95072A130). The 1A stand screw is about nine inches long, so a six-foot length would restore as many as eight stands.

[akfreak]

And here are the two smaller items.
The wax model to the right is the working nut on the long thread which moves to push the wooden member against the front bracing wooden cross piece. It works rather like an old automobile steering system!
I have made the screw holes, the "bearing" holes (which you will have to increase to match the thread you use), and the hole where you have to cut a thread to take your threaded steel rod.
I will do an engineering drawing (to best of my humble abilities!), when I am finished.

MAN I CANT WAIT! STEVEN YOU ARE THE MAN!!!!!!

[akfreak]

Thanks for the tip.
I spent a few minutes an hour ago looking at the thread and wondering what on earth it was.
I can see now that it as you say - exactly like the steering box nut and thread on my old ford.
I can also see the sense in making the working nut (last picture on the right) to take a standard nut with the 5-pitch screw nut of an appropriate size - and the solution could be useful for others. Actually this is the easiest cast of them all and could be done as an impression casting.
When the OP reads this, I hope he makes sense of this and can figure out which Acme thread he needs!

I am familiar with various Acme threads. I cant wait to hold this in my hands. Steve please let me know how I can repay you. I mean this is so wonderful. You are doing me such a huge favor. These parts are impossible to find without robbing and destroying the original stand like what happened in my case.

Steve I really cant say it enough, thank you for all of your effort. I hope that one day I will be able to return to you something that has taken this much effort. What a wonderful place this forum is. I am at a loss for words, and you know that is hard for me. WOW, Thank You, Thank You, Thanks you!

[Steven Tribe]

Before I finalise the wax casting for the "threaded" central nut, I need to know whether you can cut the Acme thread (1/2") or whether you want me to cast a captive nut within the bronze casting? I can see the sense of the later! But it will need a Acme nut here!
If you can cut a Acme thread it would, of course be nearer the original solution!

[akfreak]

I was hoping to buy the threaded rod I found this here Steve do what ever is easiest for you. I can find a nut and a handle. What you are making is going to be just perfect!

[eddie]

make a few extra. there was a guy on the forum looking for one just a few days ago.

[Robert Hughes]

Except he's using lost wax casting technique - it's a one-off.

[Steven Tribe]

Not necessarily a one-off.
It is possible to make a latex or rubber mold of the hard wax form or of the first aluminium bronze product.
The heated and softened wax can be injected. Ad infinitum!

The Grainger's 1/2 acme thread looks OK - also pricewise-
But I couldn't find the matching nut - only much larger threads?

[Michael Cienfuegos]

Not necessarily a one-off.
It is possible to make a latex or rubber mold of the hard wax form or of the first aluminium bronze product.
The heated and softened wax can be injected. Ad infinitum!

The Grainger's 1/2 acme thread looks OK - also pricewise-
But I couldn't find the matching nut - only much larger threads?

McMaster-Carr lists Acme nuts in their catalog :http://www.mcmaster.com/#general-pur...e-nuts/=doa0pz 1/2 - 10 in brass aren't too expensive.

m

[Steven Tribe]

Thanks Michael!
Very reasonable-They have this round nut in brass.

1/2"-10

0.875" (external diameter)

0.50" (thickness) - as opposed to 1" on the original fitment.

95100A103* (item number - makes a change from e**y

5.50 USD

So one route would be to drill a hole with the external diameter of the nut and then install 4 grub screws.
There is room enough for two of these Acme nuts if in doubt about replacing a 1" thread length with 1/2"! And leave a little space between to provide room for gease, drill a hole and install a grease nipple!
For me this has the advantage that expenditure is with the receiver of the castings!