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|22nd April 2009, 09:01 AM||#1|
Join Date: Apr 2009
1960's Record Cutting Lathe Bearing
I am currently building my own record cutting lathe from various bits and pieces I have collected in my shortish time here on earth and thought I'd share some of these pics with you and throw some ideas back and forth.
Ok so this project is loosely based around a Presto 14B Cutting lathe, which can be seen here:
I say loosely because as much as I have this lathe, I seem to have misplaced it! I have some bits but I believe it may have been stolen with a bunch of drag car race bits from my garage. That's another story.
In truth I believe the platter I am going to show you here is not even off the presto 14b at all.
I'd love to be an expert but I was only born in 1974 so I only know what I read. My lathe came from Studio 20 recording studios at Taylor Square in Sydney Australia (which started out back in the 1920's) from the old guy there who was 85 when I picked this gear up. He had a million stories but none that explained the parts missing or anything about it really except it cost him a small fortune.
So I am going to clean up as much as I can and build myself a cutting lathe. I have a Presto cutting head that is working and is fitted with a hill and dale type fixture on it which I will modify.
So anyway the bearing and platter:
I can tell the table is from a different lathe because in the above picture of the 14B. It sits on a massive block of cast iron. I know this because I have that bit of the lathe. It weighs about 80kgs! The center of the table is offset right to the front of this mount and there is no way my bearing will align with this cutout so that's how I know it's not the 14B's table.
Does anyone have info or history or working knowledge of these lathes? Anyone got a lathe they will sell me? I have gone on many quests to find lathes and know of most parts that I missed out on.
the platter of this table is made of Aluminum and is about 1 inch thick and 16 inch in diameter. It mounts to the bearing with a machined seat and 4 screws.
The bearing is a two part arrangement with a gearbox turning a flywheel below at a different speed to the platter. I am unsure how the platter was driven. Maybe with an idler wheel on the flywheel but there are no markings to indicate this.
It's a little hard to explain how the gearbox works but it uses 5 ball bearings mounted in an inner ring and an outer ring which I will call a ball race. The inner race is hard mounted to the bottom bearing and fly wheel, so when the flywheel spins so does the inside ring of the ball bearing race. (Sorry if I dont use all the correct terms. I am no engineer)
Upside down lower bearing which mounts the fly wheel, here you can see the 5 ball bearing.
The outer ball race is hard mounted to a sprung leaver that looks a bit like a horse shoe if you use your imagination. This ring is the clutch to stop the table spinning while the motor is still running.. You'll notice it has a little lip on it. This locates into a notch on the chrome plated housing plate. When it is locked in this notch it causes the outside ball race to remain stationary in relation to the housing, thus not spinning.
Because the outer ball race cannot spin it forces the balls to spin instead. The top bearing which the platter sits on has 5 notches cut into it that locate the 5 balls. The turning of the top platter forces the 5 balls to rotate inside the race at the same speed as the platter. Because the outside race is locked to the housing plate by the horse shoe looking thing, it forces the inner race to spin a faster speed due to it's smaller diameter (Or whatever makes it happen?!) and because the inner race is hard mounted to the bottom bearing it spins faster than the top turning the big flywheel which must be about 5 kgs at least..
Nothing like a ding bat to explain how stuff works!
there is also a bearing under the chrome plate but I have been unable to remove this plate yet. I'm not sure if it should just pop out cause right now it's pretty happy being in there.
here is a pic of the top bearing out of it's hiding hole.
So any thoughts? when holding the whole thing in your hands it's a bit hard to get a guage just how smooth it all it.
I took it to a bearing place yesterday and the engineers said it was probably one of the best feeling bearings they had seen considering how old it is. They said to clean it up and coat it with sowing machine oil. do you thinks this is best. I think once its spinning with the massive flywheel and platter it could easily move through motor oil.
I also have some questions about the lower bearing and it's spiral groove in the shaft. I imagine this is to move up oil from a well. but the case does not have a sleeve lining with a tolerance small enough to make this effective. Any thought?
Here are some more pics.
Thanks for your time and I hope you have found this interesting!.
You've Done The Right Thing
|22nd March 2011, 10:16 AM||#2|
Join Date: Mar 2011
Sure, you have a true collectible! I think that is an RCA (It looks like!) but, it possible that is a PRESTO used in radio stations to cut radio program records on thin double sided acetates (or lacquers). Did you have an actual picture of your lathe as you have? I want to see yours!
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