Motor for C&P 8x12

Hello all,

I’ve searched up and down for more information on this forum, and I remember a post with a link to good affordable motors for these presses which now, of course, I can’t seem to find.

I’ve got a 1916, 8x12 that I want to add a motor to. I know many of you recommend variable speed control systems, which are a bit more complex to set up than a single phase. Ideally, I want something that can run on standard 120v power that won’t break the bank. From what I’ve read, something around .5 to 1hp should be enough. Correct? Also, I won’t be the one installing, or doing the electric. I’ll job that out to a pro.

I’d love if some of you masters could take the time to link me to equipment you recommend or use currently and how you have it set up and mounted to your presses. I could search all day and still not be completely sure that what I end up with is what I need. It’s not for lack of trying, or searching.

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Do you have a drive pulley on the press opposite the flywheel?

maybe get “the pro” involved at this point. whoever they may be, they will be much more likely to work with equipment and technology that they are familiar with., ask for pricing options. “Don’t bring your own steak to the chef”.

No drive pulley opposite flywheel. I was planning on just using the flywheel with a v belt or similar.

You only need a 1/2hp motor at most for an 8x12. You can get a VFD and motor kit from Dealers Electric. It’ll be a three phase, 220v motor with a single phase 110v VFD. It’ll convert phase and give speed control and will run from a standard 110v outlet. However I would recommend you consult your local pro as he or she will likely have a particular supplier they work with often. It won’t be cheap, but it will be done right and you’ll know it’s safe.


Hi Hoxie! Funny you should ask…

Soooo, just recently I had to install a new* 1.5 HP motor with a variable feed interface on my old-style C&P press. Why 1.5 HP? I went with a 1.5 HP based on the consensus of some ink-stained old salty dogs and the guys I bought the motor from. :-)

As dicharry suggested, I did get a 3-phase 220v motor with a single-phase 110 VFD, but it does plug into a 220v 30-amp outlet. (When you wrote “120v”, it was not clear to me if you meant to type 110v or 220v). I did the electrical myself; while I’m not an electrician by any means, it was surprisingly easy despite it being somewhat technical. The project took me a whole Sunday, and the price was around $750-850.

I have some deadlines I have to finish today - give me until Saturday or so and I’ll post how I did it with photos on a new thread (so that way others who have the same question can find it on Briar Press). If I can post it sooner, I will.

Additionally, if you’re in the Los Angeles area, you can swing by and I can show you how I did it in person.

*The only reason I installed a new motor versus refurbishing my old Northwestern motor was that it would have taken three weeks, too long for my senses-shattering deadlines. The Northwestern motor lasted 70 years (!) so I was very hesitant to install a new motor, but with all honesty I’m a lot happier with the modern motor - it’s smooth, a lot quiter, and I have absolute control on the speed. And to be fair, the press originally didn’t have a motor, so it’s not as sacrilegious as it sounds. :-D

P.S. I’m not a master like a lot of the other men and women who post on this site, so if someone like me can figure this out, you should be able to, too. :-)

Hoxie, against the stated option of only intending to, (or being obliged to), run with a *V* belt or similar, (generally) Your stated >similar option< should be the better.

I.E. ENDLESS Flat belt, for several reasons, first to span some where near the width of the Flywheel, for maximum traction/power transmission, as would have been the norm, way back, with the fixed and free Pulley,s.!
BUT more important with, Flat Belt, the Driving Pulley to be the Crowned Style (convexed) to keep the Flat belt Running straight and true, without ANY auxiliary guides.?

Assuming, and hoping that Stateside, Endless Flat belts are an option, usually they can be produced to ANY length to suit the positioning and adjustments of the Driving pulley, as opposed to Vee belts, with comparatively coarse increments for length.!
+ If slip ever occurs, the usual trick of a little Rosin, on the inside run of the belt works wonders.
With *A* section Vee belt, not so hot.

If V.F.D. becomes an option, that opens the door to another possibility, dispense with belts altogether, turn the flywheel, with friction drive straight from the motor onto the flywheel.
Google, >Motorised Printing Press C. & P.< usually the first post that appears is a Good Example.!

The (A) section term is used, mainly because, for smaller applications, up to 1.5 H.P. (A) section is generally the Norm, with only 3/8” (or thereabouts) contact of the belt to the flywheel,?

Next step up is (generally) *B* section with 3/4” (or thereabouts) contact of the belt to the flywheel, BUT with the downside that, being that heavy, wrapping around and into the *V* of the DRIVING pulley, gets difficult, as opposed to, Supple Flat belt on Driver & Driven = Very efficient power transmission. Good Luck.

P.S. On the Heidelberg Platen, although the DRIVING Pulley is Coned & Vee format, the Belt (endless) has NO guides, whatsoever, the belt runs TRUE because the Flywheel, is CROWNED, (convexed)

This discussion is way too complex. I ran a 10 x 15 C & P with a v-belt on the flywheel for years with a variable speed motor and no problems. Now I have an 8 x 12 C & P and an 8 x 12 Brass-arm Gordon Clone. Each has an ancient generic 1/3 HP motor with flat leather belt on the flywheel.
The motor on the Gordon came with the press when I bought it 63 years ago and the one on the C & P I salvaged from a scrap heap last year. I use the same belt on both since I can only run one press at a time. It also came with the Gordon 63 years ago. I have had to repair it a few times—it takes basic sewing skills with a heavy duty needle and thread. I have been thinking about getting a replacement but I probably won’t!

I just posted Part 1: Installing/Replacing a Motor on a C&P press here

I have a couple of questions for those of you running a 3-phase motor with VFD:

- Do you use your VFD to control the press at the operator position? If so how did you mount it because most have exposed terminals (shock risk).

- My C&P 8x12 oldstyle does not have a pulley and I’ve read a few posts that mention a direct drive option to the flywheel vs a belt. I’d be interested to find out how you did this.

Images of your setup would be great. Thanks!

This is a general answer. There should not be any exposed terminal on any electrical installation! I have my VFD mounted on the wall. Once you set the speed for the job, there is really no need to change it “as you go”.

The flywheel/belt combination has a mechanical speed reduction putting less strain on the motor.
I think direct drive the flywheel would put too much strain on the motor and controller.


image: IMG_20170907_133354.jpg


I still say this is a mountain—molehill discussion. I ran a job yesterday on 8 x 12 OS with the flat belt and a cheap scrap motor, 1/3 HP. Speed was just about right and as fast as I want to go.

I ended up running a 1/2 hp motor with a v belt around the flywheel on my 8x12. It runs at about 24 impressions per minute which is a good speed for me. I help it start up and then it runs without any problems. Sure beats pumping the treadle or hand spinning the flywheel.