Horizontal Grinder Building - Thinking it through...

Natlek said:
What if you add one more wheel ? Something like this ?
CZ0hYuE.png
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There must be a hundred possible variations. Yours above is trying to maintain the hair-pin turn on the small wheel and also get maximum wrap around the drive wheel?
It would probably interfere with the platen mount I have planned. Also, adding another wheel complicates the design that much more, and it's already a little complicated.
 
Brock Cutlery said:
It does seem that gravity is going to be a bigger influence than on a vertical grinder, but then when you flip a vertical you have the same issues, and they seem to track ok, right?
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I have a kmg and flipped it horizontal and haven’t noticed any change with gravity or belt deformation that I can tell. It did take some mods to get everything running right, but that was before I flipped it.
 
No, on a vertical with standard kmg type tracking belt tension and gravity still play their part in holding the hinge down when flipped horizontal. With belt tension being the biggest factor by far in maintaining tracking position.
The crown on the wheels causes rubber/poly wheels to become concave shaped. Having two crowned wheels doubles the wear rate.
Knowing what I know now, I would have made my drive wheels flat, and probably put a dish on my tracking wheel instead of a crown. My rubber contact wheels have already become dished. This makes it very difficult to grind bevels properly. I would much rather have a contact wheel that is worn into a crown.
This is just my experience with larger wheels. I highly suspect with smaller wheels it would happen even faster.
 
mike-E said:
No, on a vertical with standard kmg type tracking belt tension and gravity still play their part in holding the hinge down when flipped horizontal. With belt tension being the biggest factor by far in maintaining tracking position.
The crown on the wheels causes rubber/poly wheels to become concave shaped. Having two crowned wheels doubles the wear rate.
Knowing what I know now, I would have made my drive wheels flat, and probably put a dish on my tracking wheel instead of a crown. My rubber contact wheels have already become dished. This makes it very difficult to grind bevels properly. I would much rather have a contact wheel that is worn into a crown.
This is just my experience with larger wheels. I highly suspect with smaller wheels it would happen even faster.
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I have a 14 inch wheel, and it is dished. I just put a square block on my work-rest with sandpaper on the face and spin the wheel. it does a decent job of restoring it.
I didn't attribute the dish to a crowned wheel though. Something to think about. Thanks Mike!
 
No problem. The crowned wheels are definitely the cause of the dishing. In a perfect world the wheels would wear into a crown because most people(I believe) tend to utilize the edges of conact wheels more than the center.
If I could, I would dish my tracking wheel and have it coated with CBN to prevent it from being worn from belt edges.
 
Natlek said:
Yes , working space around that small wheel is most important in this grinder ?
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It is important, but the only really extreme example I can think of where clearance on both sides would be an issue is this knife, and I can probably come up with an alternative method to make this one-off.
What examples are you thinking where extreme clearance is needed?

soba-knife.jpg
 
I think just grinding the inside corners/curves of something like a chef knife (or even a 10 to 12" long part of any kind) could cause some interference with the drive wheel. I think angling it out towards a 45 degree angle approaches some kind of solution, and I'm sure the piece can be rotated or flipped accordingly to clear as needed. There's never going to be a "one size fits all" for everything, so I suppose I wouldn't get too crazy worrying about it. Maybe just get some larger pieces and see how they fit onto your current mock up.

Starting to remind me of my 3 blade mower deck. Between all of the drive and idler pulleys, it took me 15 minutes to figure out how to run the belt the last time it popped off. :D
 
As mentioned before, I made a tension/tracking based on the KMG item. Here's a photo of the finished grinder - well, still got a few things to do. The tool rests are removable, you can see the general layout. The tracking adjustment works just fine, and gravity doesn't enter into anything. The belt tension keeps plenty of pressure on the wheel so it doesn't try to ride up.

IMG_2772.jpg
 
mike-E said:
This is the thread I was referring to about the horrible tracking issues with Beaumonts horizontal set up. I'm 99% sure the reason it does it is because the tracking arm is actually lifting up. If that arm lifts up a 32nd the belt will jump a mile. https://www.bladeforums.com/threads/kmg-horizontal-grinder.1479213/
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I remember that thread now. I know Harbeer is still using that grinder. How is it H?

I can't imagine the arm lifting. The pivot is at least an inch above the top of the belt, so there is no force to cause it to rise.
 
I just read the thread you linked to - I wonder if Harbeer ever got the grinder fixed for tracking? The grinder in photo above tracks just fine - both forward and reverse. Belt might move 1/8" to 1/4" when switching from forward to reverse. The tracking adjustment will move belt up 'n down pretty good.
 
Ken H> said:
I just read the thread you linked to - I wonder if Harbeer ever got the grinder fixed for tracking? The grinder in photo above tracks just fine - both forward and reverse. Belt might move 1/8" to 1/4" when switching from forward to reverse. The tracking adjustment will move belt up 'n down pretty good.
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Ken, that's great that you had such good success with your build.
I'll text Harbeer tomorrow if he doesn't answer here. I am curious too.
One interesting thing in that other thread was the thought that the 48 inch belt is more sensitive to tracking while the 72 allows for a bit of slop.
I think this is going to work out ok, but I am going to protect the plate the first few runs.
I still have a lot of work to do to get mine up and running.
 
From the comments it seems Harbeer wasn't the only one who had the same issue. In actuality there wasn't a single good comment about the tracking ever working properly for anyone.
I could be completely wrong about the cause. It just doesn't appear that the air spring is transferring pressure through the belt to the end of the tracking adjustment screw the way it does in a vertical set up when the screw is behind the wheel.
I went outside, put a belt on, and tried to push behind the tracking hinge in order to move it away from the screw. It was impossible to budge it on my grinder using one hand and pushing with my thumb. I had to grab the bottom of the wheel and pull it away. There is a LOT of pressure on the tip of that screw and that's with about 25 lbs of tension on the belt.
Regardless, on any decent grinder, a user should be able to swap belts repeatedly without worrying about tracking varying more than a 1/16" from one to the next. You should be able to go from a crawl to full motor speed without the belt changing location on the wheel.
When mines sitting horizontal with a small wheel I have yet to have it drive a belt up or down into the holder. In order for that to happen unexpectedly there is either massively insufficient belt tension,(like a few pounds or less) or the tracking hinge is pivoting.
If I were building a horizontal I would want the tracking to be rock solid and capable of moving the belt up and down on the wheels AT LEAST a 1/4" each way from center without worry of the belt jumping erratically. 1/2" would be awesome. Otherwise I would have to constantly change rest height to get to a fresh section of belt.
 
Any problem with belt tracking issue , belt jumping erratically ....is addresed to WHEELS .Wheels and belt are only moving parts on grinders .ANY wheel on grinder which is not alignment right will ACT like tracking wheel . Higher tension on belt will help to hide that problem little but will not solve .........
 
All very good points on tracking concerns. I don't know what to do other than to get my wheels mounted as true as possible, set my tension and see how it goes.
This isn't a Beaumont 48, although I am using their tracking and small wheels, both of which I am mixed about at this point. I had hoped to get away with off the shelf components for these two, but we will see....
 
I agree with Natlek here, on tracking, threading and issues with the Beaumont. I think a lot of the issues with that machine stem from holes that are not tapped straight, or are tapped over a 2B thread form limit, or are not aligned axially (or a combination of all these things).

Tapping holes in line, straight, with good fit, into a thick plate (more engagement) goes a long way toward providing good, reliable tracking. Taking it to another level would be utilizing stripper bolts/shoulder bolts for axles, so that the precision ground face of the shoulder assured perpindicularity with your base plate as well as a closer fit to your bearing IDs.

Definitely using a drill press as a tap guide is recommended.
 
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