Motorize a #32 Meat Grinder (Free Information)

Motorize a #32 Meat Grinder

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by Paul Stevens

Note: This is free information being provided for the back-to-basics "DIY" person who is trying to motorize a meat grinder or grain mill. From time to time, our customers have asked how to do this, and we have not found another source to send them to.  We do not sell the #32 meat grinder or the conversion described below.  This is an informational page that provides ideas for how I motorized one for our personal use.

It by no means is in any way intended to be expert advice or exact instructional material.  This is just how we were able to do one for our own use, and have used it very successfully.  The user assumes full responsibility for how they proceed with building or converting a grinder or mixer for their personal use.

I have to admit I was somewhat naive and ordered a #32 meat grinder, thinking I could attach a motor to the included V-groove pulley and start grinding my meat for sausage. Luckily, I did a dry run before I had a stack of fresh meat ready to be processed, because when I turned that thing on, I thought it was just going to take flight. I made several attempts with different-sized pulleys and had no success. I will also confess right off the bat that I don’t hold any fancy engineering degrees, just one from The “DIY” School of Hard Knocks, so if I don’t describe the detail to the exact MM here, don’t shoot me on the spot. I also don’t have a large machine shop or electronic equipment to measure the same RPMs. With a little trial and error, I figured it out and am pretty happy with the machine I will describe below. I hope this helps someone else dealing with the same issue.

I found all my parts locally at the farm store, but http://www.surpluscenter.com can pretty well stock what you need. Almost all the metal came from my scrap pile.

I quickly realized I needed to slow the machine to around 200 RPM or less. Plus, I needed to gear it so it had enough power to grind the toughest piece of meat and gristle that I could throw at it. Just finding a slow enough motor didn’t seem to be the answer to that problem. It still needed a transmission or gearing system to prevent bogging down. These grinders are rated at 600 lbs of meat per hour, so properly motorizing them allowed me to process all the sausage I needed in about 20 minutes. I knew our GrainMaster™ Grain Mill is recommended to run under 200 RPMs, so I used this as a guide, as no instructions come with these imported meat grinders.

I roughly calculated by setting up the pulleys and sprockets and turning them by hand, counting the revolutions it took to make one revolution on the larger pulley or sprocket. The motor pulley-to-12” pulley ratio is 8:1, meaning that for every eight turns of the motor pulley, the 12” pulley turns once. This is the first reduction. Then the ratio between the 10 x 20 roller chain sprocket and the 40 x 45 roller chain sprocket on the grinder transfers just a little over a 2:1 ratio, almost 2-1/4:1. This gear system provided me a 10:1 ratio, so at 1725 motor RPMs, my grinder is turning somewhere around 172 RPM, well below the 200 RPM that I needed. The roller chain and sprocket allow no slippage when the grinding gets tough, and I have pushed through some pretty gristly cuts of meat for sausage.

I already had the motor and the metal, so I only purchased the following parts:

• 12” pulley with ¾” bore
• Two pillow blocks 3/4” bore ( these have grease fittings)
• 14” 3/4” shaft (will need the ¾ bore rings with Allen set screws to hold the shaft in place) (see * Note below)
• 10 x 20 chain sprocket with ¾” bore ( these come in two sections and will need to have the hub welded into the sprocket; just a tack weld is all that is needed to hold them in place)
• 40 x 45 chain sprocket with 1” bore welded insert for the grinder. (40 roller chain size 45 teeth) (also see *note below)
• 60” of #40 roller chain (with splice link)
• ½” V-belt (length may vary based on the motor and pulley used).
• The smallest pulley that you can find to fit on the motor shaft ( I used a step-up pulley, thinking I might want to adjust the speeds, but have never had to take it off the first 1-1/2” size)

*Note: The ¾” shaft will need a keyway cut into one end to mount the 12” pulley and the 10 x 20 sprocket. I could have taken this to a machine shop, but since I was not making something to run at high speeds, I carefully cut a slot with a thin grinder blade back just far enough to tap in a key for both pulleys.

**Note: My imported meat grinder has a metric keyed shaft that is just less than 1”. I could not find a metric insert for the 40 x 45 grinder sprocket so I had to fashion a reducer from a thin metal pipe to slide into the bore, mine needed to be somewhere between .029 to .032MM thickness. I found a thin pipe from a 2” old curtain rod in the shop and cut the sides back so it would fit into the 1” hole while still leaving the keyway open. The larger size provided enough spring to keep it in place. This sprocket needs to be removed and reinstalled to clean the grinder and replace the cutting blades, so it should be loose but not wobbly. Without the insert, there is too much play. You could purchase a ¾” bore sprocket and have a machine shop drill it out to the metric size, or maybe you will have better luck than I had to find the metric size. I also have a dedicated Allen wrench that I keep with the grinder to remove and install this sprocket.

I started with a ¾ hp, 1725 RPM electric motor I already had in the shop. You will need one that turns clockwise when viewed from the shaft end. Most motors do turn clockwise, but some are reversible. This motor was perfect for this project because it already had an on/off switch built in. I used a truck rim and welded a 4” x 37” upright pipe into the center. At the top of the pipe, I welded a top to mount plywood. This is what the grinder bolts to, but before I drilled the holes, I assembled the rest to ensure final alignment. At 25” from the ground, I welded on 1-1/2” angle iron on both sides.

As you can see in the picture, these extend out 8” to hold the board for the catch pot as well as to hang the motor onto the machine. The angle iron for the motor mount is 14” long, as it extends back 2” past the post to extend the motor in alignment. I used two short-angle irons, eye bolts, and a long bolt so the motor's weight would pull the belt down and tighten it. The eyebolt system also allows you room to slide the motor back and forth, so alignment here is not as critical.

To keep everything aligned, I shimmed the base to the shop floor up next to a wall until I had perfectly leveled all the way around. I then used the wall to take my measurements, clamped the items in place, spot-welded, and then measured each part again before doing a final weld.

On the other side, exactly parallel for alignment I welded a 4” channel on the side of the pipe and another 5” wide x 9-1/2 channel at 25” from the floor crossways for the pillow blocks to mount the main drive shaft. Again, this has to be perfectly level as the main 12” pulley will ride on the shaft from these pillow blocks. I drilled the holes in this channel, as the shaft can be adjusted in and out.

At this point, I cleaned all my welds, primed, and painted the project. After it was dried, I mounted my pillow blocks, the shaft, the 12” pulley, and the 10 x 20 sprocket as pictured. I then mounted the 40 x 45 pulley on the grinder, used a straight edge to align it with the bottom sprocket, marked the holes for the grinder, and drilled them. The grinder-mount bolts have wing nuts, allowing the grinder to be removed and cleaned.

You will want to give just enough slack in the roller chain so that you can slide the grinder sprocket on and off, cut to the final length, and insert the splicing link.

From the picture, you will see that I extended some wood blocks and mounted a Plexiglas guard to keep fingers out of the chain sprocket. I used a heat gun to shape the guard, then secured it with wing nuts. I also installed a guard to cover the motor holes so that excess meat and moisture do not fall into the motor.

I also turned a special plunger on my lathe that fits precisely into the top of the grinder. I made this with very close tolerances so that my fingers won't slip around it and down into the auger. The plunger will push the meat down into the top of the auger, so I just lay the meat across the top and use the plunger to push it in. This is important because the auger is very close to fingers or a sleeve, which can easily get caught and pulled into it. There are extension tubes and a table available online for this grinder if you want to be even safer around this motorized machine.

 At this point, the only additional item I would add is a set of wheels to pull the assembly back onto and move it around; my two-wheel dolly works just fine. I keep it covered in the garage, awaiting the next sausage-making season.