25$ worth record clamp
- Thread starter silver_face
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- Gillette, Wyo.
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- Halfbiass...Electron Herder and Backass Woof
- Joined
- Jan 14, 2011
- Messages
- 74,244
- Location
- Gillette, Wyo.
- Tagline
- Halfbiass...Electron Herder and Backass Woof
I was taught by a tool and die maker on a Hardinge Super Precision. I LOVE that machine. This is a Hardinge second operation lathe. We had two, and a pile of parts. I went through everything and got the nicer one cleaned up and running. Sold off the turret and other bits and bought stuff I needed for this one.
The apron sits on the dovetail and clamps in place. So there is no apron travel- you have to use the cross feed which limits how far you can go. But it does have the scale underneath with the magnifier to set the compound (which I guess isn’t a compound in this case) but it’s really slick, and you can do some fancy shit in no time if you know how to use what’s there.
Under the (original!) chuck it takes 5C collets. We had two collet closers for these that apparently got scrapped. $1500 for another so I have to use the drawbar (drawpipe really) and it’s difficult to get enough tension with that.
The apron sits on the dovetail and clamps in place. So there is no apron travel- you have to use the cross feed which limits how far you can go. But it does have the scale underneath with the magnifier to set the compound (which I guess isn’t a compound in this case) but it’s really slick, and you can do some fancy shit in no time if you know how to use what’s there.
Under the (original!) chuck it takes 5C collets. We had two collet closers for these that apparently got scrapped. $1500 for another so I have to use the drawbar (drawpipe really) and it’s difficult to get enough tension with that.
- Joined
- Jan 14, 2011
- Messages
- 74,244
- Location
- Gillette, Wyo.
- Tagline
- Halfbiass...Electron Herder and Backass Woof
- Joined
- Jan 14, 2011
- Messages
- 74,244
- Location
- Gillette, Wyo.
- Tagline
- Halfbiass...Electron Herder and Backass Woof
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- Southern Indiana
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- ---6 and 7 days work week, no end in sight
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- ---not quite right
I did the first one (drawing posted earlier) out of a single chunk of aluminum.
This one has the advantage the weight is near the center, to hold the disc down, but does not add significant rotating mass, since the "clamp" bit is thin aluminum. It still ads weight to the bearing however.
Maybe having more mass at the periphery is desirable (more flywheel effect) , but I don't have a way to dynamically balance it anyway, so this seems to simply hold the record down, which is/was the idea.
I have some scrap tungsten- I could add a bit of flair (and mass) to the center of the brass...
EDIT: make the lower bit out of plexiglass! Then you can read the label while it's on!
This one has the advantage the weight is near the center, to hold the disc down, but does not add significant rotating mass, since the "clamp" bit is thin aluminum. It still ads weight to the bearing however.
Maybe having more mass at the periphery is desirable (more flywheel effect) , but I don't have a way to dynamically balance it anyway, so this seems to simply hold the record down, which is/was the idea.
I have some scrap tungsten- I could add a bit of flair (and mass) to the center of the brass...
EDIT: make the lower bit out of plexiglass! Then you can read the label while it's on!
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- ---not quite right
Cool idea with the plexi! Would suit the Prisma! I would bet that more mass at the periphery would be beneficial, how much may not be easily measurable/negligible. As far as balancing, years ago a friend built a “mass moment of inertia” dynomometer for testing kart racing engines. It was a flywheel toughly 30” diameter and 2” thick made from 4140 annealed. He was paranoid about the balance as it was to spin around 3000 rpm. After carful machining of the flywheel and axle he sent it for balance. It was perfect as it was. Basically what I’m getting at is modern steels are pretty consistent throughout and at 33 1/3 on 3” diameter you would need serious alien tech to detect any off balance!
