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" 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 only an informational page to provide ideas on how I was able to motorize 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 all responsibility on how they proceed in building or converting a grinder or mixer for their own personal use.
I have to admit that I was rather naive and ordered a #32 meat grinder thinking I could just slap a motor onto the V-groove pulley that was included 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 tried several attempts with different sized pulleys and didn’t have any luck what so ever. 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 big machine shop or electronic gadgets to calculate the exact RPMs. With a little trial and error, I did figure it out and am pretty happy with the machine that I will describe below. I hope this will help someone else out dealing with this same issue.
I found all my parts locally at the farm store, but http://www.surpluscenter.com can pretty well stock you with what you will need. Most all the metal came from my scrap pile.
I pretty quickly realized I needed to slow that machine down to around 200 RPMs 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 that would not let it bog down. These grinders are rated at 600 lbs of meat per hour so motorizing it correctly meant I could process about 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, which means I set the pulley and sprockets up and turned them by hand counting the revolutions it took to make one revolution on the larger pulley or sprocket. The motor pulley to the 12” pulley gives me an 8:1 ratio, meaning for every 8 turns of the motor pulley it turns the 12” pulley one time. This is the first reduction. Then the ratio between the 10 x 20 roller chain sprocket to 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 never have 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 back 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 that I had in the shop and cut the sides back so it would fit into the 1” hole but still leave the keyway open. The larger size allowed enough spring so that it stays in place. This sprocket will need to be taken on and off to clean the grinder and to change out the cutting blades, so you will want it loose but just not wobbly loose. 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 take this sprocket on and off.
I started off with a ¾ hp 1725 RPM electric motor that I already had in the shop. You will need one that turns clockwise looking at the shaft end. Most motors do turn clockwise, but some are reversible. This motor was perfect for this project as it already had an on and off switch built into it. I used a truck rim and welded a 4”x 37” long upright pipe into the center. At the top of the pipe, I welded a top to mount a piece of plywood. This is what the grinder bolts to, but before I drilled the holes I built the rest to have a 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 weight of the motor will pull down and tighten the belt. The eye bolt system also allows you room to slide the motor back and forth so alignment here is not as critical.
In order to keep everything aligned, I shimmed the base to the shop floor up next to a wall until I have perfectly leveled all the way around. I then used the wall to take my measurements from, 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 did drill the holes on 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 and used a straight edge to align it up with the bottom sprocket, marked my holes for the grinder and drilled them. The grinder mount bolts have wing nuts so the grinder can be taken off 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 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 and then fastened it with wing bolts. I also made a guard to cover the motor holes so excess meat and moister will not fall into the motor.
I also turned a special plunger on my lathe that fits exactly into the top of the grinder, I made this with a very close tolerance so that it will not allow my fingers to slip around it on down into the auger. The plunger will push meat all the way down into to the top of the auger, so all I have to do is lay the meat across the top and then use the plunger to push meat into the top. This is very important as the auger is very close for fingers or a sleeve to get easily caught and pulled into the auger. There is an extension tube and table on the Internet for this grinder if you want to be even safer around this motorized machine.
At this point, the only extra I might add is a set of wheels to pull the assembly back onto and move around, my two-wheel dolly works just fine. I keep it covered in the garage awaiting the next sausage making season.