how to make a idler wheel?

[Black Forest]

I need to make a top wheel for my belt grinder that I am building. I will make it from steel. I will make it 90mm diameter. My round stock is 115mm diameter. The wheel will be 50mm wide when finished. The round stock is much longer so I will cut off what I need to make the wheel.

The wheel will have two bearings mounted. Obviously one on each side. The bearings are 20mm inside diameter, 47mm outside.

So how would you all go about making this wheel. The tricky part will be the taper on the face to help with the tracking of the belt.

I was thinking to cut the length to 70mm and turn down a stub to mount the wheel after I turn the first taper and then cut off the stub when I am done with the taper.

[Peter.]

Heavy old wheel there!

If your lathe is big enough to hold the stock in the jaws with no center I would just chuck up the stock, turn the OD parallel to the largest size, face it off, bore the hub for axle clearance, turn the side features and bearing recess, then cut it off in my bandsaw, clock up the OD in my 4-jaw and repeat for the other side.

Finally hold it by a bearing recess, dial in the OD and turn the crown.

If you can't hold the stock in your lathe I would cut off the stock 1/2" over-length and do the same except for turning the length of the wheel to size in the process.

[strokersix]

I would:

Cut off a blank equal to your sheave width plus chuck jaw depth. Turn OD features, face, bore one bearing pocket and bore thru at about 42mm diameter. Part off excess with bandsaw. Dial in the 42mm bore in your 4-jaw, face and bore second bearing pocket. This way the second bearing pocket is the only functional feature not created in the first setup.

Note that the crown can be in 1/3's. Doesn't have to be a radius. Flat in center then tapered off both sides. This will give a nice flat spot for the jaws to grab in your second setup.

[JCHannum]

I would slice off a piece, face it to width, bore the bearing details, then make a stub arbor to fit the minor bearing ID and turn and radius the face as the final operation.

A collection of stub arbors will serve you well in the future, they are easily made and modified to suit the job at hand. I usually make them long to permit using both ends for different applications.

[Carld]

Yep, I'm with JC. I would cut to length, face ends, bore for bearings, mount on fixed mandrel or expandable mandrel, turn down to size, cut 1 deg angle each side of center for centering effect and your done.

[J Tiers]

+1 on the mount on mandrel idea.

That ensures the bore and OD are concentric, among other matters of convenience and stock usage. At least it does if the mandrel is on center.

I have a bunch of regular tapered mandrels, which go between centers, and are great for this type work. The taper is under 0.1mm over the whole length, so they hold the part well.

For something like that, having a long bore, the better type is a 2 part expanding mandrel, OR a stub mandrel you make for the job (and put away for later re-use). The latter is substantially cheaper.

[Rustybolt]

For my one inch belt sander I used a wheel from a shopping cart. Worked very well.

[lakeside53]

The profile taper is easy, but holding the wheel by the tapered profile isn't. I'd do that part last.

I used water pump cartridges (bearings/shafts are mounted in a sealed sleeve). I first made a straight-through precision bore for the bearing cartidge (undersized bore, aluminum heated to insert the cartridge), mounted the 5 inch wheel on an expanding mandrel, turned the top profile then both face profiles. The tiny amount left near the arbor was cleaned up later.

Boring both bearings pockets from one side can be tricky if you intend the bearings to seat against shoulders. If you make a through bore and mount individual bearings you could groove and insert circlips for bearing shoulders. But.. definitely think about how to achieve the concentric operations without dismounting the wheel.


Why steel? Aluminum works fine. Not sure what rpm you'll be turning, but steel is a lot of mass. Also, make it a little wider than the 2 inch belt. Mine ended up 2 3/16, and helps extend the life of the the belt edges.






Idler and tracking mechanism assembly.

[sasquatch]

Re: Rustybolt's using a wheel off a shopping cart??????

Can you post a pic?? I find it strange that a wheel like that would be suitable , especially for the rpms.???

[Rosco-P]

What not start with a single wheel industrial caster, cast iron, semi steel, etc. with a "rubber" outer tire. Might need a little truing for high speed operations, but it will already have bearings and the face can be crowned. I've seen them (on HSM) used as the basis for stationary belt sanders.