2x72 Belt Grinder Build

M

Mikerags

Joined
Jul 24, 2013
Messages
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Hello, long time reader of the forum. First time posting here. I am about to start a 2x72 belt grinder build. It is KMG clone based on the "knife-grinder.pdf" plans by Michael Clerc. My goal is building a high quality, but cost effective grinder. Under $1k for all parts and materials.

After reviewing the plans, I found a few items that didn't exactly line up, plus I want it to be direct drive with a VFD, so I decided to model it and make the modifications. Worst case, once I finish, I can put out some plans and drawings.

I am picking up the 0.75" material tomorrow to start piecing together the frame. That should keep me busy for a few days. I will finish the rest of the modeling (tooling arms, roller wheels, etc...) as I go.

Before I start, I was looking for anyone who has already built one of these to provide any feedback or things they would have changed if they did it over again?

Below is the grinder frame:
Grinder%20Frame%201.jpg

Grinder%20Frame%202.jpg


Also, I don't like how the tracking adjustment screw lands half way on the hole for the tracking wheel shaft. I will likely move this to fall in the center of the shaft or down below the shaft.
Tracking%20Screw.jpg


Let me know if anyone has any other feedback or suggestions on improvements? Thanks.
 
I haven't built one of these, but I'll make a couple of observations if you like. Since your not using bearing mounts, the rear main support upright does not need to be that wide and might interfere with your motor. I think you will regret using .75 material for your motor mounting plate. Even with the 1/2" mounting plate that is used on the "Grinder in a box", the drive wheel does not slide entirely onto the typical motor shaft. By using 3/4" material you're going to lose an additional 1/4". On your tracking / idler mount. I would consider raising the hole location for the tracking wheel shaft which will allow for the tracking screw to land on the plate and not the shaft as you show. This is how it's done on the GIB. One other thing, I would do some modeling to determine the height of your tracking & tension arm supports based on what spring or gas shock you plan on using. You really need for the tension and tracking arm to be in a horizontal position when the spring/shock is loaded. If it angles up to any degree it will screw up your tracking.

Hope this helps and good luck with your build!
 
i 100% agree with the comments above, and would add that since you're going direct drive to make it flip horizontal. the 3/4'' motor mount plate is going to be a hassle in that position, like nc biker said.
 
Thanks for the feedback. I picked the some of the metal today. The 0.75"x6.0" ten foot steel bars weights more than I thought at 150lbs each and unloading them from the back of the truck was quite the feat by myself. Luckily no broken toes. I was going to adjust all of the metal to use 3/4", but after actually feeling the weight, I will stick with everything else being 0.5".

mike-E, when you say the motor mount is going to be a hassle in that position, was the comment only about the 3/4" and proximity to the rear support, or is there something else about that position?


Updates are as follows:
1. Added a second left receiver for a tooling arm
2. Adjusted the motor mount to 0.5" from 0.75"
3. Shortened the back support mount by 0.5" to leave more room for the motor enclosure

Grinder%20Frame%202%20V0.2.jpg

Grinder%20Frame%201%20V0.2.jpg



I am also considering the following changes:
1. Moving the rear motor mount underneath the right receiver and eliminating the rear support. I'm not sure I like this change, but may have to modify the model to see what it looks like. This would require raising the two receivers ~2in higher, so there is more room for the motor. Plus the receivers would be cantilevered off the support, possibly allowing it to flex downward.
2. Will likely make a rotating mount so I can go horizontal. I think I can modify the base at a later time once I get the vertical setup.

Goal is to get all of the materials by Friday, so I can build over the weekend.

Thanks again for the help so far.
 
im assuming you have access to a mill? if i were building that grinder i would narrow the rear upright by 1/2'' and mount the motor plate to the edge of the upright. i would also notch the base out 1/2'' deep and extend the motor plate downward into the notch. this will let you bolt to the face of the plate. also you'll want to have a threaded hole on the right side of the receiver to push the tooling arm over to the left.
 
mike-E said:
im assuming you have access to a mill? if i were building that grinder i would narrow the rear upright by 1/2'' and mount the motor plate to the edge of the upright. i would also notch the base out 1/2'' deep and extend the motor plate downward into the notch. this will let you bolt to the face of the plate. also you'll want to have a threaded hole on the right side of the receiver to push the tooling arm over to the left.
Click to expand...

good suggestions
 
mike-E said:
im assuming you have access to a mill? if i were building that grinder i would narrow the rear upright by 1/2'' and mount the motor plate to the edge of the upright. i would also notch the base out 1/2'' deep and extend the motor plate downward into the notch. this will let you bolt to the face of the plate. also you'll want to have a threaded hole on the right side of the receiver to push the tooling arm over to the left.
Click to expand...

Yes, a CNC mill will be used to produce the parts. I am looking to understand the reasons behind your comments. Is this to take the 4 motor support bolts out of shear and bending and have the load transferred direct from motor support to rear/base support plates?
 
Mikerags said:
Yes, a CNC mill will be used to produce the parts. I am looking to understand the reasons behind your comments. Is this to take the 4 motor support bolts out of shear and bending and have the load transferred direct from motor support to rear/base support plates?
Click to expand...
not only will the motor mount and bolts be stronger (yes for out of shear) that way, you'll also have better access to the bolts that hold the plate to the base. of course you could just eliminate the motor mount plate and bolt the motor to the base. many c-face motors come with feet too.
 
Mike, take a look at this thread - http://www.bladeforums.com/forums/showthread.php/1234634-New-Grinder-for-me

I did pretty much what you've got going a yr or so ago. 1/2" is plenty thick enough for material - I used aluminum because I like working with aluminum and it's less weight to move around since I move my grinder outside when doing lots of grinding.

Note my rear upright support in relation to the peckerhead on the motor - I cut my rear support on an angle thinking it would miss, but still interferred with peckerhead. I rolled my motor up with peckerhead on top to clear rear support. Not a big deal.

I think if you're wanting two toolarm holders, they tend to work better vertical - other folks can comment on that.

On the two grinders I've built I had the tracking wheel adjustment screw to land on the axle of the tracking wheel - no real reason, just handy place and works just fine. With 1/2" plate, everything just lines up nicely.

if i were building that grinder i would narrow the rear upright by 1/2'' and mount the motor plate to the edge of the upright. i would also notch the base out 1/2'' deep and extend the motor plate downward into the notch.
Click to expand...

Mike-E, you wrote the above - I see what you're saying, but don't fully understand the reason - the plate will be countersunk so the 56C motor will mount nicely and extend thru the 1/2" plate. This gives the standard motor shaft a tad over an 1" into the drive wheel which is plenty to hold drive wheel. If I bolted my 1/2" plate to the outside of upright moving the motor another 1/2" out, that would move my drive wheel a tad more. I think it would still work, but it would be close. There's a tad less than 1/2" of space between drive wheel and motor mount now.

edit: I just read your response to to Mikerags questoins and I guess I still don't fully understand. I'm missing something for sure.

Mikerags - building grinders is FUN and you'll surely enjoy the grinder! With your CNC mill you can work magic!

Ken H>
 
Ken H> said:
Mike, take a look at this thread - http://www.bladeforums.com/forums/showthread.php/1234634-New-Grinder-for-me

I did pretty much what you've got going a yr or so ago. 1/2" is plenty thick enough for material - I used aluminum because I like working with aluminum and it's less weight to move around since I move my grinder outside when doing lots of grinding.

Note my rear upright support in relation to the peckerhead on the motor - I cut my rear support on an angle thinking it would miss, but still interferred with peckerhead. I rolled my motor up with peckerhead on top to clear rear support. Not a big deal.

I think if you're wanting two toolarm holders, they tend to work better vertical - other folks can comment on that.

On the two grinders I've built I had the tracking wheel adjustment screw to land on the axle of the tracking wheel - no real reason, just handy place and works just fine. With 1/2" plate, everything just lines up nicely.



Mike-E, you wrote the above - I see what you're saying, but don't fully understand the reason - the plate will be countersunk so the 56C motor will mount nicely and extend thru the 1/2" plate. This gives the standard motor shaft a tad over an 1" into the drive wheel which is plenty to hold drive wheel. If I bolted my 1/2" plate to the outside of upright moving the motor another 1/2" out, that would move my drive wheel a tad more. I think it would still work, but it would be close. There's a tad less than 1/2" of space between drive wheel and motor mount now.

edit: I just read your response to to Mikerags questoins and I guess I still don't fully understand. I'm missing something for sure.

Mikerags - building grinders is FUN and you'll surely enjoy the grinder! With your CNC mill you can work magic!

Ken H>
Click to expand...
Ken, im assuming this is a bolt together design, i could be wrong. if the motor mount plate gets welded he could use 3/8 steel and be just fine. if he bolts the plate the way it is in the last iteration he will likely use 1/4'' bolts, 5/16'' at most in the edge of the 1/2'' plate. if he bolts to the edge of the 3/4'' upright he can use 3/8 bolts easily. also if the base has a notch for the mount plate to sit in it will help maintain squareness of the motor. say for instance he had five 1/4'' bolts in the edge of the plate, 2 on the side, and three along the bottom(he only shows four). you could probably grab the corner of the motor mount plate and bend or break those bolts with hand pressure. if the plate is bolted through the face he doesnt have to worry about shearing those bolts.
 
If you take a look at the motor plate in the link I provided you can see the 1/4" bolts bolting the motor mounting plate - there are only two of them bolting to the rear vertical support, but there are also two 1/4" bolts in the base up into motor mount plate - "IF" you can break that with your hands, remind me not to shake hands with somebody that strong. VERY solid and strong with it supported from two sides. You can see the bolts in my grinder how it's bolted together - no welds at all. I was thinking this grinder was to be bolted together, looks like bolts in his drawings. With his CNC milling machine lining everything up will be a snap - VERY nice. My little desktop CNC mill is nowhere near large enough for that work.

Welding the motor mount plate would be good - BUT better be sure it's really lined up good before welding solid.

Ken H>
 
mike-E, Thanks for the reply. After thinking about it, I am not sure why I left the motor mount in the design, as the motor I am using will have a base plate. I may try it with the motor mount first and eliminate it after I give the grinder a try. Yes, the frame is being bolted together with 1/4"-20 bolts.


Ken H>, Thanks for the information. I did quite a bit of searching prior to the build but missed your thread. Wish I would have found it sooner, as I would have likely built it out of aluminum, which is the material I mostly work with. I was originally concerned with rigidity, so steel it is.
The motor you used is the same I selected. Should be here shortly. How has it worked out for you? Is your VFD still working for you as well?
 
Fwiw I built my grinder in a box out of 3/8" and it's plenty heavy. I'm currently designing a tilting 2x72 and plan to make it out of 3/16" or 1/4". I've been using 3/16" for disc grinder mounts and it's plenty rigid enough. I know it will be rigid enough as the tw-90 is made out of like 3/16" I believe and that is a fine machine. Other than that the only thing I would do differently is use more welding and less bolts.
 
Mikerags - I have though if I were building another grinder, I just might forego the motor mounting plate and use the motor baseplate and bolt to grinder base. I think that would work just fine, and might even have an advantage - certainly simpler. BUT - I think a brace similar to the motor mount plate would still be needed to brace up the rear vertical support.

Yes, the motor is working just fine - and VFD is just fine. I do have to clean filters from time to time.

You'll be surprised how often you'll use the horizontal position and it's easy to add.

Ken H>
 
Kevin, I also built a "GIB" which has a 1/2 inch welded frame and I tilt it horizontal on a wooden platform. It is easy to tilt and very steady. Here's a couple photos and a short video clip. Larry
gpQo5ll.jpg


aa7Xcekl.jpg


[video=youtube;IIqdNZaB-Uc]https://www.youtube.com/watch?v=IIqdNZaB-Uc[/video]
 
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