dd turntable torque

[studiorp]

Hello to all, today I have a question for you :
a strobe of a dd turntable from 3.0-3.5 kg/cm of torque, jump while you are cutting makrolon discs , or the dots remains stationary ?

Many thanks and cheers.
Raffaello.

[maniman]

you have flutter problems .... not ?

[studiorp]

Yes, actually I have flutter's problem, so I am thinking to buy a turntable with this torque, but I want be secure to do the right thing ...

[maniman]

yes , im in the same with a 6N overhead project , someone here talks about the Reloop RP 6000 , have adjustable torque until 4.5 Kg per cm2.

the other way im thinking is buy an old transcription plate , and try to adapt a classic 1500(50hz) / 1800(60hz) bodine/qrk/russco motor over there , but someone can ilustrate us better than me , i need help with this too.

im tryng with a Lenco L60 turntable , but the Lenco shaft diameter its a little bigger than other turntables , and the 6N not fit well , no talk about making the drive hole ... i dont know .... we need some light over this.

http://www.reloop.com/reloop-rp-6000-mk6-b

[studiorp]

I have already changed 3 motors, but all have same problems : flutters and rumble on cutting head, that then go on disc while I am cutting it...

A Reloop 6000 could be super ok, but my question remain open, because yes, a 6000 have 4.5 kg/cm, but I asked if a 3.5 kg/cm could be already good...

Is there someone that cut on makrolon with turntables with this torque ?

[maniman]

Presto 6N cutting PVC for me not , is the only can say. But im think how smooth runs the mechanism is more important than directly the materials involved , im in the same situation , sorry.

[pentlandsound]

I'd be interested in any answers to the original post, as I'm in a similar situation - trying to choose a good direct-drive turntable for indenting/embossing on polycarbonate. There are several turntables on the DJ market that promise up to 5kg.cm of torque, but this is described as 'starting torque' - to give an idea of the quickness with which the platter can go from stationary to the desired playing speed. I've heard (somewhere) that, to get a measure of 'constant torque' - that is, how well the turntable will perform under a sustained load such as a cutting stylus - the measure is about half the 'starting torque' figure.

I'm currently using a Lenco 75 idler-drive, which has a very heavy platter, but find that embossing records much bigger than 20cm (8 inches) causes it to drag unacceptably. My other turntable, a KAM DDX-750, wobbled and stuttered hopelessly when I tried it for disc-cutting, but then it was very cheap!

Has anyone tried the above-mentioned Reloop, or the Stanton 150 which has a similar specification?

[studiorp]

For me could be ok already a Kam ddx 4500 with 3.5 kg/cm of torque, 3 speed and pitch control until 50%.
The difference than Reloop 6000 is the torque, because it has 4.5, while Kam 3.5.
Perhaps already a Technics 1200 is enough, if consider for example that Souri's machine and Vinylium lathe works with this turntable, that have only 1.2 kg/cm, then with changes on electronic board, torque can increase, but I don't know until value...

[studiorp]

Then, another thing: I don't know if makrolon is more soft to cutting than an acetate disc...

[opcode66]

then with changes on electronic board, torque can increase, but I don't know until value...

FYI, the torque mod for the Technics 1200 is very simple to do. But, the side effect is less accurate speed control. I.E. it is no longer exactly quartz locked.

[Angus McCarthy]

This thread got me wondering just how much torque my Russco Studio Pro puts out, but wouldn't you know it - nobody seems to want to say!

[markrob]

Hi,

You could measure the stall torque with a pull meter. Here is a link to a cheap one:

http://www.micromark.com/digital-pull-meter,9577.html

For PM DC motor, that should be the same as when running at speed. Torque is directly proportional to motor current. So I assume they would limit the stall current to protect the motor and driver. To make the measurment, attach a string to the outside of the platter and connect to the pull tester. Read the force in grams or oz and measure the radius of the platter. Torque will be grams x radius (cm) or oz. X radius (in).

Mark

[Angus McCarthy]

Ah, thanks Mark. It seems so straightforward knowing how to measure it now. I may have a spring scale that could do roughly the same job.