The Secret Society of Lathe Trolls

Lewis D

Hello, I have a presto 8DG and the feed drive comes of the main drive shaft through a pully band and then onto the feed shaft. The pitch is not very variable if I want to do a wide pitched 78 and I can only get 12 mins a side on a 12'' at 45 rpm.

So, I want to have a variable seperate motor attached to the feed with a knob I can simply turn to increas or decrease the pitch.

And the question is, which motor do I use?

I would preferably like it to go from about 5rpm to a very high rpm so I can do a very fast wind out. The top rpm needs to be as much so that I can do a finished lead out spiral over about 1 inch in half a revolution at 45 rpm, roughly.

To give you an idea of the gears, when the feed shaft turns at 45 rpm, the record cuts 1 inch in 3 mins.

The motor also needs to be very strong with high torque.

Does such a motor exist, that is completely variable? If so, which one?

Thanks alot,
Lewis

Amp Doc · Joined: 21 Jun 2007 Posts: 108 Location: UK

Vexta do a good range of dc servo motors you can get them with or without gearboxes they come with a control board so you can ajust speed easly they have start stop and brake controls and even a rpm output. the speed is set by a 0 to 5v control signal. I use a 50w one to drive my turntable it has very high torque and is very stable I think this would work well. motor model number is AXHH450KC you can get specs of the web. motor cntrol board is AXHD50K. they use 24V dc and the contol is cmos compatable. Acording to the manual the AXH450KC-20 has a RPM of 5-150 and 32lb per inch torque and a AXH450KC-10 has a RPM of 10-300and a torque of 16lb per inch. Hope this helps...
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emorritt · Joined: 09 Nov 2006 Posts: 53 Location: Louisiana

Lewis, you might want to check out this company's website: http://www.anaheimautomation.com/ I use one of their motors to drive an old Presto lathe I cut 78's on, and the speed is constant and smooth throughout the range. Nice torque as well. The motor I use is one of their brushless DC's with an integrated driver. Wiring the power supply (I use a Radio Shack 30VDC wall wart) and control pot is pretty simple. Hope this helps.

JayDC · Posted: Wed Dec 26, 2007 6:05 am Post subject:

emmorit,
Do you have the specs for your motor?

emorritt · Joined: 09 Nov 2006 Posts: 53 Location: Louisiana

Jay the part number on the order reply they sent me was BLWR23MD3S-36V-4000. You can see it at this link http://www.anaheimautomation.com/brushlessdcmotordrivers.aspx and it's the second one in the lower price list. After the expense and time of having the original motor rewound this works like a dream. Absolutely NO motor noise on a Presto!