Film-Tech Forum ARCHIVE: help needed with PR1F motor rewind (HFC)

This is topic help needed with PR1F motor rewind (HFC) in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

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Posted by Bill Brandenstein (Member # 7758) on 04-19-2016, 11:44 PM:

I'm trying to help a friend determine what's missing with an HFC motor rewind (full model number on it is PR1F-HD) that plugs in and flies full speed. There's no pedal with it, nor a knob or anything else in the little L-shaped side opening. It came with a smaller hand-crank HFC unit and half-split reels to adapt the spindles for 35mm usage. While we've no use for 35mm, I might take it off his hands for my 16mm usage IF we can fix this for a reasonable price. Advice?

Posted by Tony Bandiera Jr (Member # 2365) on 04-20-2016, 10:21 AM:

You are in luck..the HFC rewinder uses a small "universal" (brush-type) motor. You can easily get a speed control that plugs into the rewinder from Grainger or Harbor Freight (they are usually listed under "drill or router speed control");

Here's the one from Harbor Freight ($18.99):

Linky

Posted by Bill Brandenstein (Member # 7758) on 04-20-2016, 12:48 PM:

Very cool, Tony. Thanks for the link. Forgive my ignorance, but what you're implying is that a brush-type motor can be controlled, then, by any variable rheostat? That's a good price for the occasion, too.

Posted by Tony Bandiera Jr (Member # 2365) on 04-20-2016, 01:47 PM:

You are correct, a rheostat can be used to control a brush-type motor. Earlier sewing machines' foot pedals were simply a rheostat of nichrome wire with multiple contact taps. (Often those rewinders had that style of control originally). A variac will control a brush type motor too....avoid most standard "light dimmers" as they put out a waveform that can burn up any motor.

Oh, and on the Harbor Freight model....reading the reviews, seems as they often come with the "low trim" set incorrectly, so that they won't cut the speed very much. There is a trim pot inside you can adjust with an insulated screwdriver to set the low speed range better. (I haven't purchased one yet to go into more detail, but it should be easy to figure out.)

Posted by Louis Bornwasser (Member # 3063) on 04-21-2016, 08:51 AM:

Neumade used off-the-shelf Dayton speed controls from WW Grainger.

Posted by Jim Cassedy (Member # 4115) on 04-21-2016, 02:35 PM:

quote: Tony Bandiera Jr
Earlier sewing machines' foot pedals were simply a rheostat of
nichrome wire with multiple contact taps

Many years ago I fixed my mom's 1940's vintage Singer sewing
machine, and it used a "carbon-pile" speed control footswitch.

Inside, a number of carbon/graphite disks, each a little larger than a
dime, were loosely contained inside a ceramic insulator tube with metal
contacts at each end. (Think of a paper roll of dimes you'd get at the bank)

Stepping on the footswitch compressed the disks together. The more
they were compressed, the lower the resistance, and the faster the
motor ran. Eventually, if you continued stepping down harder on the
footswitch, you'd reach a spot where a set of metal contacts would
bypass the carbon pile entirely, & the motor would run at full speed.

Posted by Bill Brandenstein (Member # 7758) on 04-22-2016, 02:42 PM:

Very helpful, guys. Too bad a footswitch such as Singer used couldn't be had cheaply at this point. Well, maybe as 2nd-hand it is. But the Harbor Freight item is hard to beat, unless you have no hands free and need to stop the film suddenly!

Posted by Bill Brandenstein (Member # 7758) on 04-22-2016, 07:06 PM:

Actually, Google turns up a couple of pedal options that are both inexpensive and appear to be of the correct type:

Moto Tool Foot Pedal from Amazon

Foot Pedal Speed Control from American Science Surplus

Comments? Warnings?

Posted by Tony Bandiera Jr (Member # 2365) on 04-22-2016, 09:21 PM:

Bill, the specs and reviews indicate both are not suitable for this application.

The Amazon one has a lot of reviews indicating overheating, sparking or smoking failures. One mentioned reverse wiring as well (hot and neutral swapped).

The other is rated for only 200 watts, the HFC rewinders draw more than that under the load of a reel of film.

Stick with the Harbor Freight or Grainger options.

Posted by Bill Brandenstein (Member # 7758) on 04-23-2016, 05:01 PM:

Again, Tony, thank you. Tremendously helpful of you!