Steel idle wheels ok?

B

Brian.Evans

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I have a local machinist friend that is willing to help me shave costs on my EERF build by making my wheels. However, they'd be made from steel rather than aluminum. Will that be ok? I'm just using them as wheels, not contact wheels.

I will probably have him make four 2"x2" 1/2" bore wheels for the flat platen and slack wheel arms, a 4"x(what width?) 5/8" bore for the drive wheel and a 4"x (what width?) for the tracking wheel.

Questions:
What width for the Tracking and drive wheels.
Should the drive wheel be flat or crowned and should it be knurled for better performance?
How crowned should the tracking wheel be?
I have seen a couple of grinders with big tracking wheels (like 5"). It makes the "triangle" of the three wheels flatter. Is this a good thing or a bad thing?
What modifications do I need to make the Grizzly 10" wheel work with a tooling arm?

And the big one--will steel work for the wheels instead of aluminum?

Thanks all.
 
medicevans said:
I have a local machinist friend that is willing to help me shave costs on my EERF build by making my wheels. However, they'd be made from steel rather than aluminum. Will that be ok? I'm just using them as wheels, not contact wheels.

I will probably have him make four 2"x2" 1/2" bore wheels for the flat platen and slack wheel arms, a 4"x(what width?) 5/8" bore for the drive wheel and a 4"x (what width?) for the tracking wheel.

Questions:
What width for the Tracking and drive wheels.
Should the drive wheel be flat or crowned and should it be knurled for better performance?
How crowned should the tracking wheel be?
I have seen a couple of grinders with big tracking wheels (like 5"). It makes the "triangle" of the three wheels flatter. Is this a good thing or a bad thing?
What modifications do I need to make the Grizzly 10" wheel work with a tooling arm?

And the big one--will steel work for the wheels instead of aluminum?

Thanks all.
Click to expand...

Nothing wrong with steel wheels in my opinion.
Al material is more expensive than steel, but in production Al will work faster and cost less.


Questions:
What width for the Tracking and drive wheels.

Have a look at Beaumont and knifemakerusa website for wheel specs.

Should the drive wheel be flat or crowned and should it be knurled for better performance?
Crown, sure a degree or two per side won't hurt on drive and tracking
I wouldn't knurl.


I have seen a couple of grinders with big tracking wheels (like 5"). It makes the "triangle" of the three wheels flatter. Is this a good thing or a bad thing?
I think bigger won't hurt

What modifications do I need to make the Grizzly 10" wheel work with a tooling arm?
located on center in a lathe or mill, bored to fit bearings
outside trued to the new center, balanced.


R82RS bearings will give you the 1/2" shaft diameter for all your wheels.
 
Dang.

Thanks Sam. Even bearing part numbers. I'll tell you what, this place kicks butt! :D
 
The larger drive wheel will give you faster belt speeds. Steel wheels shouldn't be any issues.
 
I'm going to run a VFD. I was really more thinking about a larger tracking wheel. I like the way it looked and how the belt seemed to bend more smoothly around the wheel with a bigger wheel at the top of the machine.
 
Steel will be heavier, but works great.
Be aware of the weight issue on the tracking wheel, you will need to adjust spring weight to compensate for the heavier wheel weight.

Don't knurl anything, but crown is good, my own are either 3 or 5 degrees per side, and track like a champ, I didn't to a true radius crown...

The bigger the wheel, the better they track too. Because of more area in contact with the tracking wheel I think.
It also makes for bigger angles in the triangle, not flatter angles.
 
Awesome. Thanks guys. I will have to think about the larger tracking wheel and how large I want to go.

I think we were talking about the same thing, just different ways of saying it. The top angle will be more obtuse, which I would think would make it work better, but at a certain point would make it work worse, because it would act like a 2 wheel machine with a contact wheel, right?

Now I have to figure out how to make a small wheel attachment and I'll be set.
 
Well, actually the top angle will be more Acute (angle gets smaller)
More Obtuse at the contact wheel (angle gets larger)

Triangles always have 180* of angle inside.

The smaller the wheels are, the longer the bottom of the triangle becomes (getting closer to 2 wheel territory) so the top angle is opening up as the wheel gets smaller.
That angle is closing up as the wheel gets bigger.
 
Both of these drawings have the same 72" belt length.

10" Contact wheel on left, tracking up top, 4" drive wheel on the right.

FWIW, the 8" tracking wheel has approximately 3X the length of contact with the belt compared to the 4" wheel.

Angles.jpg
 
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When you're turning your idler wheels, you may want to bore the inside large enough for a spacer to fit. So, if you use 1/2" i.d. bearings, the through bore needs to be 3/4" or so, big enough that a steel spacer sleeve with +/- .100 walls will slide over the axle bolt between bearings, with enough clearance not to contact the i.d. of the wheel.

Spacers are not strictly necessary, but the bearings will run smoother and last longer and can be snugged tighter without side load if you use them. You can buy them in the Hillman drawers or whatever your hardware store has, then perhaps your machinist friend can turn them to length when making the wheels.
 
Brian, thanks for the drawing. I guess I thought the pivot for the tracking wheel would get lower the larger the wheel became. Your drawing is perfect and I'm saving it to chew on a bit at a time so I can think on it more.

Salem, I will have to think about what you're saying a bit before I understand. I'm confused as to how exactly I should keep the wheels on the shaft in the first place. You don't have one broken down I can see a picture of, do you? I don't know enough about bearings and side loads, ect, to make an informed decision.
 
Salem Straub said:
When you're turning your idler wheels, you may want to bore the inside large enough for a spacer to fit. So, if you use 1/2" i.d. bearings, the through bore needs to be 3/4" or so, big enough that a steel spacer sleeve with +/- .100 walls will slide over the axle bolt between bearings, with enough clearance not to contact the i.d. of the wheel.

Spacers are not strictly necessary, but the bearings will run smoother and last longer and can be snugged tighter without side load if you use them. You can buy them in the Hillman drawers or whatever your hardware store has, then perhaps your machinist friend can turn them to length when making the wheels.
Click to expand...

+1
I tried my first rollers (made from steel as well) without the spacer, and bearings would die prematurely, and getting the tension right on the bearing was a pain. I bored them out for a spacer, and the bearings have lasted 2yrs so far, as a daily use sander. If Salem doesn't have a pic I can snap you one in the next few days.
 
There are 2 pivots on the tracking for these 3 wheel grinders.
Tension pivot, and tracking pivot.
Where the tracking wheels axle ends up on the tension pivot arc varies, but has an ideal sweet spot.
That sweet spot is hard to explain in simple terms, on the 'net without a lot of typing, and some extra drawings...

Suffice it to say that the only thing that varies a great amount is the in and out adjustment on the contact attachment.
The Drive wheel is fixed, the tracking wheels center point should end up in almost the same spot along the tension arc regardless of the attachment on the contact end, or the diameter of the tracking wheel.
From an ideal engineering standpoint, the tracking wheel does move a bit along the tension arc depending on the attachment on the contact end, but not nearly as much as the left end of the triangle does.

In relatively simple terms, ideally the tracking axis should be perpendicular to a line bisecting the top angle of the belt....

In reality, it matters very little.
On my grinders, which aren't the same as yours, I shoot for proper belt tension when the tensioning arm is horizontal, regardless of attachment.
Therefore, my tracking wheel is always in basically the same spot.
 
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ecos said:
+1
I tried my first rollers (made from steel as well) without the spacer, and bearings would die prematurely, and getting the tension right on the bearing was a pain. I bored them out for a spacer, and the bearings have lasted 2yrs so far, as a daily use sander. If Salem doesn't have a pic I can snap you one in the next few days.
Click to expand...

Oh, please do. It would really help my buddy, who is a talented machinist make the wheels. I don't know enough to tell him what to do.
 
Fellhoelter said:
There are 2 pivots on the tracking for these 3 wheel grinders.
Tension pivot, and tracking pivot.
Where the tracking wheels axle ends up on the tension pivot arc varies, but has an ideal sweet spot.
That sweet spot is hard to explain in simple terms, on the 'net without a lot of typing, and some extra drawings...

Suffice it to say that the only thing that varies a great amount is the in and out adjustment on the contact attachment.
The Drive wheel is fixed, the tracking wheels center point should end up in almost the same spot along the tension arc regardless of the attachment on the contact end, or the diameter of the tracking wheel.
From an ideal engineering standpoint, the tracking wheel does move a bit along the tension arc depending on the attachment on the contact end, but not nearly as much as the left end of the triangle does.

In relatively simple terms, ideally the tracking axis should be perpendicular to a line bisecting the top angle of the belt....

In reality, it matters very little.
On my grinders, which aren't the same as yours, I shoot for proper belt tension when the tensioning arm is horizontal, regardless of attachment.
Therefore, my tracking wheel is always in basically the same spot.
Click to expand...

That actually makes sense and I appreciate the extra time it took to explain it. I enjoy knowing the "why" behind how stuff works. If you know the why, you're better able to adapt previous knowledge to current situations.
 
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