modding a Vanrock/Atom to cut 5" discs

[ericschafer]

Lathe Trolls, I throw myself upon your mercy! My name is Eric, Feeble of Mechanics but Swift and Mighty of Bad Ideas!

I am looking for a way to modify my Atom A-101 to be able to emboss 5" discs along with its current ability to emboss 7" discs. Since it is the transport itself that moves on this machine, it seems like the only way to accomplish that is to somehow build a mount for the cutter arm 2" inches to the left of the existing one. Or it could mean affixing some sort of sliding mechanism to where the current cutterhead is mounted, to allow the cutterhead itself to be moved 2" closer to the center of the record (although this seems unbalanced to me). Or perhaps a combination of ideas, where the current mount is extended 2" to allow the cutter arm to be moved between 5" and 7" positions.

O Stalwart Lathe Trolls, please administer the Righteous Slap of Truth if I have once again produced an idea that couldn't, shouldn't, and wouldn't be practiced in the service of the Noble Art of Record Cutting. But if you should find some small merit in this scheme, can you please bestow upon me your advice and blessings as I attempt to prevent turning this machine into a Japanese boat anchor?

Many thanks!
Eric

[boogievan]

I read that Emil Berliner's first gramophone records were 5" diameter. But they were intended as a child's toy, since the sound quality at disk radii less than 3 inches is rather compromised.
As for the mod - since it would still be kewl to emboss on 5" disks - move the mount 1.0" to cut at 5.0" instead of 7.0". This is because 1 inch of radius (which is what you'd be moving the new mount through) = 2 inches of disk diameter, innit? We lathe trolls are twice as nice as anyone else. √

- Boogie (If you see me rockin'...don't come knockin')

[mrd]

Not sure why you need to modify it it all to do this as it's all possible as is:

Have the head up. Move the platter using the fastforward to get to 5 inch. Drop the head, ffw a short lead in, move to recording as normal.

If you go some way between the standing and fast forward switch switch position (I think it's here, it's been a while since I've fired mine up) you can get it to spin even without moving so much (I used to use this to heat a blank with a lamp) .

If you want to have some more manual control of some aspects of the automation, the slide for the bed and the preset switches do hit some microswitches along the way which you could tap into and have a remote for. Particularly the stop/return function. i've thought about doing this a couple of times but other projects got in the way and I'm thinking of parting ways with the Atom

[ericschafer]

Great points!

boogievan, you're totally right, I only need to go 1 inch over. Thanks!

mrd, this thing shuts off the audio and forward movement and lights a light when it hits that "ending" microswitch, which doesn't give very much usuable surface on a 5" disc. Any idea how I would mod so the microswitch is switchable between 5" and 7" ending position?

[mrd]

Good point, like I say it's been a while! My memory of it is that there's a microswitch which cuts the audio feed as well as switches the bed motor off, though I may be mis remembering it. you could have an inline interrupt for that micro switch potentially with your own microswitch wired when you are ready to hit the end. It could extend the capability of the 7 inch too (though potentially make unplayable for auto-return turntables if that's a concern). My unit is with a friend at the moment who has been kindly been recapping it, but I might have another play with it when it's back as this has got me thinking about it again and what it's capable of. In the past I did locked grooves with mine by removing the belt under the platter which drives forward movement for the bed, as it's the same motor that spins the turntable that drives the slow forward movment of the bed - be interesting (but harder) to modify this