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Post by cablehack on Oct 10, 2013 6:48:48 GMT
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Post by ChrisJ on Oct 10, 2013 13:02:58 GMT
Were the screws on the CKs aluminum? On the CAs they are either plated Everdur Bronze or Monel.
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Grigg
5 Cubic Foot
Posts: 95
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Post by Grigg on Oct 10, 2013 15:08:45 GMT
He says they were aluminum in the blog. The screws in our 37 CK are also aluminum.
I've wondered where one would get replacement original design screws. They are slotted and have a very low head, not something you see very often. Need to look in some of my old machinist hand books and see if they show the same thing and give specifications and a name.
Grigg
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Post by ChrisJ on Oct 10, 2013 15:12:45 GMT
Good chance that they were custom made being GE was likely buying hundreds of thousands if not millions of them.
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Post by cablehack on Oct 10, 2013 22:41:23 GMT
Back in those days the screws would have been an in house product. It's interesting to note the variation in metals used over the years, finally ending up with stainless steel (1940/41 Flatop film www.youtube.com/watch?v=EG5LAyAfq8k ). I'm curious why they needed to do this. However, it's a good thing ordinary steel screws were not used, otherwise they'd all have to be drilled out as they rust into position. |
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Grigg
5 Cubic Foot
Posts: 95
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Post by Grigg on Oct 14, 2013 23:37:23 GMT
I removed a screw from the 37 CK and measured it. Also looked in all my machinist handbooks and related reference books to try to match it to something.
The head is similar diameter to a standard round head but not as high. It is smaller than a truss head... really doesn't match up to a common or standard head profile/ shape.
They're #10 screws but have an uncommon 30 threads to the inch, not the 32 I was expecting to find.
Looking in everything I have all the hand books except one made absolutely no mention of a 10-30 screw thread. The one that did claimed it to be an A.S.M.E. standard size, but like I said no mention of it in all the screw thread data in about a dozen other handbooks and even some books only on screw thread standards.
So looks like it would be highly unlikely to find replacements other than used.
Grigg
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Post by cablehack on Oct 15, 2013 1:20:30 GMT
The replacement screws I bought from Antique Appliances are 10-32. However, they are not precisely the same as the original. The extra tightness is noticeable, although they do go in all the way.
Had I not been able to purchase those, I was going to re tap with 4mm.
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Post by jhigdon2 on Oct 15, 2013 6:56:20 GMT
Exactly right. I have measured them also and found them to be quite unusual at approx. 30 t.p.i. none of my thread gauges match them,either sae or metric. At one time I wondered if they could be some kind of whitworth ??
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Grigg
5 Cubic Foot
Posts: 95
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Post by Grigg on Oct 15, 2013 18:49:18 GMT
I tried a 10-32 screw and started well but got tight, just as you'd expect for having a slightly wrong wrong pitch. I suspect not much harm would be done to retap with 10-32 and use common screws if you had to. It perfectly matched the thread pitch gauge so I'm sure they're 30 threads per inch, and diameter is right on for a #10. As uncommon as it sounds it's not unheard of apparently, just took some searching to find confirmation that 10-30 was a real size at one time. If you need a 10-30 tap they can be had quite reasonably as a "special thread" tap. Here's one source among many. www.victornet.com/cgi-bin/victor/productlist.html?subdepartments=Special+Thread+Taps:618%2C1170%2C1171Grigg |
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Grigg
5 Cubic Foot
Posts: 95
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Post by Grigg on Oct 15, 2013 18:53:29 GMT
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Post by ChrisJ on Oct 15, 2013 19:01:49 GMT
That would be me.  |
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Post by ChrisJ on Oct 15, 2013 19:04:47 GMT
To quote Bruce on Fordbarn. "To keep it on topic, information is taken from "Mechanic's Vest Pocket Reference Book", compiled by John H. Wolfe, Sc.D., Supervisor, Apprentice School, Ford Motor Co., Dearborn. #10 screws are listed in 30, 32, and 24. There are now-obsolete thread counts for many sizes of bolt and screw. Taps and some fasteners in oddball sizes can generally be found at places like MSC Industrial Supply." And Pete from Fordbarn. "It is a standard "olde timey pitch". Here is where you can get them cheap." victornet.com/subdepartments/Special-Pitch-Taps-up-to-1/2-inch/1260.html |
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