Variable speed motor for lpi?

This is where record cutters raise questions about cutting, and trade wisdom and experiment results. We love Scully, Neumann, Presto, & Rek-O-Kut lathes and Wilcox-Gay Recordios (among others). We are excited by the various modern pro and semi-pro systems, too, in production and development. We use strange, extinct disc-based dictation machines. And other stuff, too.

Moderators: piaptk, tragwag, Steve E., Aussie0zborn

User avatar
sameal
Posts: 309
Joined: Sun May 24, 2015 10:13 pm
Location: Milwaukee, wi
Contact:

Re: Variable speed motor for lpi?

Post: # 44315Unread post sameal
Mon Oct 10, 2016 8:42 pm

Ok so. Any hints on a dual motor setup? As that would be ideal?

User avatar
sameal
Posts: 309
Joined: Sun May 24, 2015 10:13 pm
Location: Milwaukee, wi
Contact:

Re: Variable speed motor for lpi?

Post: # 44321Unread post sameal
Tue Oct 11, 2016 12:37 pm

Im thinking of a high and low motor maybe?

User avatar
Soulbear
Posts: 525
Joined: Tue Nov 04, 2014 11:56 am

Re: Variable speed motor for lpi?

Post: # 44323Unread post Soulbear
Tue Oct 11, 2016 2:23 pm

Hi Sameal,
Did you check out my "Lazarus Lathe Project" Thread?? I used a Single Gearmotor and PWM Controller to drive the Overhead on this DR33C Lathe. The "Cutting Speed" is "Set" with a 100K Potentiometer. This gives me a L.P.I. Cutting "Range" of around 64 up to 204 L.P.I. I also then added a Potentiometer "Bypass Circuit" of a 10K Fixed Resistor and a "Momentary Push Button" in Parallel with the Potentiometer. Depressing the Push Button causes the Gearmotor to Run at a "Greatly Increased Speed" to that which is Set by the Potentiometer, and which should be OK for the Cutting of "Lead-in and Run-Out" Grooves. I also added a Cut-Out Micro-Switch, so that the Gearmotor Stops completely, at the Correct Locked-Groove Diameter. I first tried the 50R.P.M. Gearmotor Model, which gave great Cutting Speeds, but had nothing in Reserve, to Run the Leadscrew at the Higher Speeds needed for Lead-Ins/Run-Outs. I've now got fitted a 240R.P.M. Gearmotor which so far seems OK, giving me Lead-In and Run-Out Speeds at a 60% ish P.W.M. Speed Controller Duty Cycle, but obviously this has a lot less Torque than the 50R.P.M. Gearmotor Model. I'll be repeating this Modification, when I get around to restoring my Poltz Freres Lathe. On that Modification I think I'm going to go "Down the Middle" and use the 160 R.P.M. Gearmotor Model. I think this will give me a decent Torque Increase compared to the 240R.P.M. Gearmotor Model, and still have enough "Speed Reserves" to be able to Cut at the Higher Speeds needed for Lead-In and Run-Out Grooves. Remember too, that both the BSR DR33C and the Poltz Freres Lathes are both being converted from 78 R.P.M. Lathes and their Leadscrews were both driven at 1:1 or Unity at this 78 R.P.M. speed, in each case, via a Platter Spindle Mounted Pulley.
Hope this Helps
Regards :wink: :P :D Soulbear

User avatar
sameal
Posts: 309
Joined: Sun May 24, 2015 10:13 pm
Location: Milwaukee, wi
Contact:

Re: Variable speed motor for lpi?

Post: # 46312Unread post sameal
Sun Mar 05, 2017 1:10 pm

Hey soulbear,

Did you ever get that motor "in the middle?"

Im going with this type of setup on the presto for now. Im considering which motor to pick up

User avatar
Soulbear
Posts: 525
Joined: Tue Nov 04, 2014 11:56 am

Re: Variable speed motor for lpi?

Post: # 46315Unread post Soulbear
Sun Mar 05, 2017 4:39 pm

Hi Sameal,
sameal wrote:Did you ever get that motor "in the middle?"
Well, yes and no. I bought a 160RPM GW31ZY Gearmotor, but I've had a spell in Hospital with some Health Issues, so I've not been well enough to test it yet, or make any more progress with the "Lazarus Lathe Project" Added to which, I've been packing up "Stuff" in anticipation of moving to my new home (Moving Day Tomorrow!!) so I've simply not had the time to devote to the many Lathe-related "Projects" I have on the go, and which are still in need of much more work.

The 160RPM Gearmotor was actually purchased as a "Just in Case" item, in the event of any potential issues with the 240RPM Model, which I will only find out for sure, after I start Cutting. It may well be the case that the 240RPM Model's Output could be marginal, once the Stylus is doing it's thing on a blank. What I can say for what it's worth, is that I'm pretty convinced that the 160RPM Gearmotor should give you the "Best of Both Worlds" in that it should undoubtedly have a "Gain" in Torque over the 240RPM Model, and still have sufficient speed reserves over and above the 50RPM Model, when called upon for the higher speeds needed for Cutting "Lead-Ins and Run-Outs" I think on balance, as a "Happy Medium" the 160RPM GW31ZY Model, would probably be the way to go. I'm using a PWM Motor Speed Controller which also usefully Displays the PWM Duty Cycle as a Percentage, so the Display therefore lends itself very readily, to facilitate the making of a "Recording Length" Timing Chart
Hope this Helps
Regards :wink: :P :D Soulbear

User avatar
sameal
Posts: 309
Joined: Sun May 24, 2015 10:13 pm
Location: Milwaukee, wi
Contact:

Re: Variable speed motor for lpi?

Post: # 46320Unread post sameal
Sun Mar 05, 2017 10:58 pm

Hope all is well and you get better. This forum needs ya!

I picked up the motor and the pwm. I got a few gears on watch, but i have no idea what im doing on that end. Im thinking of buying a bunch of different ratios and playing around.

Post Reply