Upgraded my grinder!

Lyon

Well-Known Member
Hi all,

I finally got my new grinder built. I went with a 21 inch wheel for hollow grinding and added a KMG tool arm on the opposite end. My reasoning was that if I was going to build a variable speed grinder and invest in the motor and controls I may as well stretch my money as far as I could. My current grinder is a grizzley 2X72 so there wasn't anything that I could salvage for the new build.

The 21 inch wheel is a pair of 1 inch repurposed bandsaw wheels that have been rubber coated by sunray. My plan was to make it a convertible 2 inch or 1 inch grinding wheel. I am not done fiddling with it but it looks like that probably won't happen any time soon. I will need to get setup with a lathe cutter and true the wheel as it is spinning so that I can get it to run a little more true. I had made assumptions about the process that sunray would do when coating them and when looking at the wheel after I got it back I noticed that it wasn't as prefectly true as I had thought. In summary, I did save about $300 on the wheel vs buying a new one that size from sunray but it is going to take some extra work to get it like I would want. I did get the wheels usable in the 2 inch configuration with some shimming for now so at least I have that going for me.

Some of the design considerations that I settled on:

You will need to use a 2 X 132 belt. Because of the extra length over a 2 X 72 belt and needing/wanting a variable speed controller, adding the tool arm was a natural continuation. It only cost me an extra $15 for a forward/stop/reverse switch in the controller to change the belt direction depending on the side of the grinder I was working on. While 2x132 belts don't have as big of a variety of belt types it is still the second most popular. That being said they are not as easy to track down and will require some more effort to find the supplier you want and you may end up ordering from a couple of online stores to get everything you need which is what I had to do.

I went with an air cylinder for the tracking arm mainly because it sounded kind of cool. It also allows you to get a good range of precise adjustments for the belt tension. I went with a 3/4 bore cylinder which is too small so I will be stepping up to 1.5 inch bore.

Because of the length of the grinder and me being 6 feet tall without my work boots on there was no way for a bench mount to work. I was lucky to find a 10 inch piece of well casing for the post. The top piece is 12 X 34 X .5 inches and the bottom is 20 X 24 X 3/8 inch. I went ahead and bought them new vs dumpster diving at a scrap yard. The quality of the cuts are also WAY better than I could have done and that alone was worth the cost to me. I also didn't want the top to warp from welding or vibrate so I went thick which let me drill and tap directly into the plate for mounting the pillow block bearings. The bottom plate I drilled holes for a 7/16 bolt at each corner so that I could stabilize it vs bolting it down. Seams pretty solid so far :biggrin:.

I mounted the 1.5 horse motor under the top plate and stepped it down 2-1 so it has plenty of power and a max SFM of 4300.

Next week I will post up a pic comparing the grind vs a 10 inch wheel.

IMG_20150416_172405_515.jpgIMG_20150416_172318_649.jpg
 
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Lyon,
Very cool looking machine. Its been years and I don't know where to send now but I use to use a scalloped edge belt on my convex large fighter blades that I had made up.

So if you settle on a particular belt you like in the 2 x 132 in weight an d grit you may be able to have a batch made up?
 
Oh man, now you've got me thinking! That looks great. I built my first grinder, but there are a couple things I'd like to do a little different. When I see yours, I'm thinking build one like that with a height adjustable column, maybe with a cylinder from a cherry picker in the column. You could work standing or sitting. I also find that I'm not always happy with the fixed height on mine switching from platen to hollow to slack, etc. You've gave me something to think about for sure. Good job.
 
Oh man, now you've got me thinking! That looks great. I built my first grinder, but there are a couple things I'd like to do a little different. When I see yours, I'm thinking build one like that with a height adjustable column, maybe with a cylinder from a cherry picker in the column. You could work standing or sitting. I also find that I'm not always happy with the fixed height on mine switching from platen to hollow to slack, etc. You've gave me something to think about for sure. Good job.


I was going to do an adjustable column but I just went with what I had. Bruce Bumps grinder has 2 pieces of large square pipe nested together with a bottle jack on the bottom and a home make cam lock at the top.

As far as the height goes it works out pretty well because the wheel has such a large " sweet spot" for grinding (because of the large diameter) I was able to set the platen on the other end right were I wanted it. Grinding when I am sitting feels like I am trying to do it with one hand behind my back so I never really considered trying to do that..... Maybe I can make a stool that has a cherry picker column on the bottom:biggrin:.


Thanks all for the kind words.
 
Amazing grinding setup!!! Do you take care to invert the belt to second the printed on direction when grinding in reverse mode?
My grinder is low, and I grind sitting on a chair, with my wrists supported by my knees or the work rest if i'm using it...i find it a very steady position
 
Thanks!

Yeah, some belts require flipping but most don't.

Sitting ok but for me I like to have my arms at 90 degrees and transfer weight from side to side. I also like the mobility of getting up close or to the sides easier.

The general theory tho is to use the largest muscle groups as possible. In theory it will give more control and better endurance.
 
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Matt the grinder came out great. I like the idea you can grind with the big hollow or just move to the other end for a flat grind without any adjustments really. Nice!
 
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