Crank Shaft Thread Sizes

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CDBPDX
Victor V
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Crank Shaft Thread Sizes

Post by CDBPDX »

I have 2 early Victor motors in need of crank shafts. The appropriate gears are present and one shaft is present but broken. Both cranks are female, one is ¼", the other is 5/16". I took the cranks to several hardware stores and none of the bolts had matching threads. I would like to get some dies and make my own shafts, but I don't know what thread patterns to use. Any thoughts?

The folks at the hardware stores don't seem to know any more about these than I do, not very encouraging.

Anyway, any help would be appreciated.

Thanks!

Cliff
Cliff's Vintage Music Shoppe, Castle Rock, WA
http://www.youtube.com/watch?v=QIz_IpaVrW8

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Victrola-Monkey
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Re: Crank Shaft Thread Sizes

Post by Victrola-Monkey »

Just this past week I went to two of the biggest bolt suppliers in the area seeking replacement spares for all the bolts used on the Type 1 changer and ran into the same dilemma. It appears that the thread count per inch of the bolts from our phonograph time period falls in between the count for fine thread and course thread today.

Today ¼” bolts have a 20 count for course and a 28 count for fine. All the ¼” bolts I was looking for were 24 count. I was also looking for #10 sized bolts and they only make 24 and 32 count today, but I needed 28 count. Additionally I was looking for #5 sized bolts and they only make them in 40 count and I needed 48 count.

I was out of luck on the bolts but I did buy a very handy bolt size tool which contains a chart of all today’s bolts and the thread counts for fine and course. This tool shows for 5/16” bolts the thread counts available today are 18 and 24. It you tried both the course and fine in that size with no luck, then my guess is that it is a 22 count. I would do an internet search to see if such an animal exists.

I did find on the internet that certain lengths of the ¼-24 bolts exist but they all seemed to be in chrome and designed as replacement bolts for early motorcycles of the same phonograph time period. I also saw there were taps and dies available in that size.

I’m not sure if all of Victor Talking Machine Company’s threads have a count that’s in between course and fine... Matter of fact, I know not all of them aren’t, or at least the metal threads of the four threaded holes at the bottom of Victrola and Electrola cabinets used to hold them in place in the original crates is a ⅜” course thread (16 count) and I thought the ⅜” Victrola cranks were fine thread (24 count), both are available today.
Last edited by Victrola-Monkey on Sun Jul 08, 2018 1:42 pm, edited 1 time in total.

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Victrola-Monkey
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Re: Crank Shaft Thread Sizes

Post by Victrola-Monkey »

I should have mentioned where you could borrow a ¼”-24 bolt from a Type 1 changer Victrola or Electrola to verify in your ¼” crank, if you have one. You would need to remove the record platter and the wood deck surrounding it to gain access to the top of the changer. From the top, there are three ¼”-24 bolts that screw into and hold the motor to the changer plate (there are no nuts), two of which are right in front. I would remove one of those two to test out. The other two will still secure the motor so no problems would arise from doing this.

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Phono-Phan
Victor V
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Re: Crank Shaft Thread Sizes

Post by Phono-Phan »

Wayne,
Try McMaster-Carr. They carry a large variety of fasteners. Fastenal would also be a good resource. Are you sure that it is ¼"? In my Model A, there are #12-24 bolts. They are very close to ¼".

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Victrola-Monkey
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Re: Crank Shaft Thread Sizes

Post by Victrola-Monkey »

Ken,

Thanks for the tip, I will check their web sites.

I dug up and pulled out a spare little female crank handle I have believed is a ¼" and went to screw in my bolt I was told and therefore had believed to be a ¼"-24 bolt. It seems a bit wiggly and it only screws in half the distance I believe it should. I measured that bolt and it reads .237" in diameter, not quite ¼". So I believe you are correct in that it may be a #12 bolt.

I looked at and checked some victrola motor mount bolts and some victrola horn pipe connecting bolts I have and they are the same size bolts. Though my handy bolt guide tool chart shows that there are 24 thread course and 28 thread counts fine on today's #12 bolts, the tool has no #12 hole to verify its size. I will go back to the bolt stores and see if they have #12-24 bolts.

Thanks for clearing this up for me. It's very important and timely to learn this because that the hole in the aluminum replacement part for the pot metal collar arm that goes around the tone arm that clamps it tight is this size. The foundry was going to just use ¼"-20 and I wanted to use the same as original but needed to confirm the size.

-Wayne

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CDBPDX
Victor V
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Re: Crank Shaft Thread Sizes

Post by CDBPDX »

Thanks for the help. I did find a ¼"-24 die on Amazon, should be here soon.
Cliff's Vintage Music Shoppe, Castle Rock, WA
http://www.youtube.com/watch?v=QIz_IpaVrW8

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Victrola-Monkey
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Re: Crank Shaft Thread Sizes

Post by Victrola-Monkey »

Nope, my bolts are not #12-24, since a nut of that size does not fit on. It must be ¼”-24. I did find that there’s lots of bolts that are used on the Victrola of this size:

Back panel bolts
Tone arm mounting bolts
Motor board hold-down bolts
Tone arm board to horn flange bolts

As well as those previously mentioned for the changer machines:

Tone arm collar clamp bolt
Motor mount to changer plate bolts
Horn pipe connection bolts
Record size gear assembly base mount bolts

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CDBPDX
Victor V
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Re: Crank Shaft Thread Sizes

Post by CDBPDX »

My ¼" - 24 die came today and it worked great! Now, if I could just figure out how to drill a 3/32" hole in the new shaft, I'll have it made. The drill bit just spins, no cutting at all. Tried several drill bit, different brands, I have a starter drill bit and the 3/32" bit drills down as far as the starter bit went, but no further. I am about ½ way through the first of 2 holes needed, that's as far as the starter bit went.

Any suggestions?

Cliff
Cliff's Vintage Music Shoppe, Castle Rock, WA
http://www.youtube.com/watch?v=QIz_IpaVrW8

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Victrola-Monkey
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Re: Crank Shaft Thread Sizes

Post by Victrola-Monkey »

The bit has gotta be a cobalt bit and use cutting oil, not lubricating oil. Certainly you’re using a drill press, right?

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CDBPDX
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Re: Crank Shaft Thread Sizes

Post by CDBPDX »

Victrola-Monkey wrote:The bit has gotta be a cobalt bit and use cutting oil, not lubricating oil. Certainly you’re using a drill press, right?
No drill press, using lubricating oil, I've used a half dozen different bits, some say cobalt. All the same result. Guess I need a drill press if I'm going to do this regularly...
Cliff's Vintage Music Shoppe, Castle Rock, WA
http://www.youtube.com/watch?v=QIz_IpaVrW8

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