DIY 2x72 Grinder

 DIY 2 x 72″ Belt Grinder

I wanted to build a 2 x 72″ belt grinder. I did a bunch of research and formulated a plan as follows.

The best resource I used a lot was http://dcknives.blogspot.com/p/2-x-72-belt-grinder.html 

Others that helped

https://www.instructables.com/id/2X72-Belt-Grinder/

https://www.makingstuff.info/projects/belt_grinder?AspxAutoDetectCookieSupport=1

https://www.youtube.com/watch?v=n03JraRgD2k

https://www.youtube.com/watch?v=a_RlL1O-bK4

      (folding unit)   

http://jerswoodshop.com/2×72-tilting-belt-grinder/

https://www.youtube.com/watch?v=H9iUww8yGxI

This is the order I placed at onlinemetals.com for 

2 pieces @ $14.01/piece Mild Steel A36 Hot Rolled Rectangle 0.25″ x 8″ x 12″

2 piece @ $22.07/piece Mild Steel A500 Hot Rolled Square Tube 1.5″ x 0.25″ x 36″

1 piece @ $42.93/piece Mild Steel A500 Hot Rolled Square Tube 2″ x 0.25″ x 48″

1 piece @ $25.77/piece Mild Steel A500 Hot Rolled Square Tube 2″ x 0.25″ x 24″

and from oregonblademaker.com/

Belt Grinder D-Backing plate for 2×72″ knife making grinder with wheels

Belt Grinder Tracking Wheel for 2×72″ knife making grinder with bolt axle

Belt Grinder Drive Wheel for 2×72″ knife making grinder 5/8″ bore

Belt Grinder Flat Platen for 2×72″ knife making grinder, hot rolled steel 2″

I had a 3 hp Lesson 220v electric motor that was used.

I also ordered these from Amazon

2″ X 72″ Knife Makers Fine Grit Sanding Belts, 6 Pack Assortment

2 X 72 Inch Knife Sharpening Sanding Belts – Ultra Fine Grits – 4 Pack Assortment

2″ X 72″ Knife Makers Coarse Grit Sanding Belts, 6 Pack Assortment

I had the basic builds done in a day. I followed the basic build from

http://dcknives.blogspot.com/p/2-x-72-belt-grinder.html

with just a few modifications.

The base was an old Harbor Freight shaper that I parted out.

I originally want to make this fold to go horizontal. I’ve bolted it to the base instead of welding it so I can still do that if I decide to. I will wait to see how many times I wish I could flip it.

I wanted to add a VFD, but it seems it’s not a good idea with this motor. Unfortunately, this Leeson 115048.00 is a single-phase capacitor-start type motor, so there are no variable frequency drives or other speed controllers that I could find capable of driving this. If it were a three-phase, then there would be several solutions. I may look for a cheap treadmill and replace the motor someday. We’ll see how it plays out.

All the parts arrived pretty quickly from oregon blademaker except the drive wheel. It somehow got left off. An email to them got me one in the mail, but it still pushed back completion by over a week. Some of the images show the grinder with the pulley still on. The drive wheel has been installed however.

Add the end to the belt adjuster post ( not my best welding job) I tried a spring from a storm door like mentioned on dkknives but it didn’t work very well. I will need to find a better option.

These 2″ x 1/4″ pieces were cut on the bandsaw. 3 at 10″ and 1 at 4″ just like the plan called for.

I drilled the through holes for the adjuster wheel before cutting it to shape to ensure I could get a straight drill.

The angle was cut with a cut off wheel in the grinder. I really need to get a metal chop saw! I didn’t have a bolt with enough threads for the retainer bolt, so I had to add some more threads.

At the end of day 1, it was in somewhat working order. I suppose we could have called it fully functional if the drive wheel had arrived with the rest of the oregon blademaker supplies.

I decided to bolt the grinder to the base with a piece of angle iron. This to was bolted in case I changed the configuration later on (like making it fold to horizontal)

I intentionally put the face shield hanger over the switch so I can’t turn the grinder on without grabbing the face shield.

I welded a 2” piece of rod to the bolts to make a wing style bolt.

Drive Wheel close up

Drive wheel close up

Tracking Wheel close up

Tracking Wheel close up

Platen Wheel close up

Platen

Keep in mind used treadmill can be had for pretty cheap usually and are good sources for motors and controls. Also used table saws (especially the  older Craftsman) which would make a great base and potentially a motor as well. Update: I found the guide to be to wide. I would have to bend over it, so I cut it down to 4″

Here is the variable speed upgrade i decided on after some use:

When I built my belt grinder i used a 2 hp single phase motor I had on hand. I wasn’t exactly sure how much I’d use the grinder, and I wasn’t sure how necessary variable speed would be. I since discovered it is one of the most used pieces of equipment in my shop, and almost invaluable for making knives. I also found myself wishing I could slow the belt down quit often.

So I decided to upgrade. I purchased these two items.

—IronHorse premium efficiency AC induction motor, general purpose and inverter duty, 2hp, 3-phase, 208-230/460 VAC, 3600rpm, TEFC, 56C/HC frame, rolled steel, rigid base/C-face mount

—

KB Electronics, 9520, KBAC-27D (Gray), 1.5;2HP, 1-Phase, 110-120V;200-240V (Input), Nema 4X Enclosure, Variable Frequency Drives

Unfortunately for me, I did’t order the VFD from Amazon. It came and I hooked it up and it didn’t work. The status light was doing a slow red blink. A search on the internet suggested a bad unit. I called KB and sure enough, they said the unit was shorted. I could return it to them, they would assess it, and fix it or send a new one. I was not a happy camper and did not want to wait that long. I called State Motor and Control Solutions where i had ordered it online and they immediately sent out a new VFD, but I had to pay the $30 return shipping on the bad one (I would have had to pay this anyway). Not ideal, and not perfect customer service, but better than the manufacturer. I should have ordered from Amazon I guess.

My motor came wired for 220.

I’m not sure what the U,V, and W stand for but they get connected to the 3 lines on the motor. When i connected mine, the motor was running backwards for my grinder. Another quick search and I discovered changing two wires on the motor changes direction. It worked like a charm.

Switching two lines coming into the motor got it running in the correct direction.

Being able to control the belt is a big help, especially grinding bevels. It’s also helpful for sanding wood that’s prone to burn. I’m finding the variable speed a huge help and use it almost every time i use the grinder now. It’s well worth the extra effort if you’re thinking of building a grinder.