strip sander fix pt 2

[wa2crk]

After truing the wheel on the lathe return to the drill press and open the 1/4” hole up to 3/8”.
Then using the 7/8” Forstner bit again line up the wheel by inserting the 7/8”bit into one of the holes and drill to a depth of 11/32”.

drilling the bearing seat.jpg (118.91 KiB) Viewed 1339 times

Check the depth by inserting a 1603 bearing into the hole and make sure that the bearing is flush with the face of the wheel and then remove the bearing. Flip the piece over end repeat the process on the opposite face to a depth of 3/4”. Note that this is NOT deep enough.
Fit both bearings into their bores and insert the OEM stepped bolt to check the depth. It will probably be necessary to tap the bearings into their bores.
After checking the depth the bolt will fall short and not come through the rear bearing. Remove the bearings and re-drill the deeper hole until you can get a fit like this.

finalfinal assembly and design.jpg (90.02 KiB) Viewed 1339 times

Here is the final assembly laid out on the bench

assembly sequence.jpg (93.43 KiB) Viewed 1339 times

Here are some comparisons of the OEM wheel tracking and the wooden wheel tracking.

OEM wheel tracking.jpg (101.92 KiB) Viewed 1339 times

This is the tracking of the new wheel.

belt tracking.jpg (88.92 KiB) Viewed 1339 times

My first attempt at turning the wheel I included a step to mimic the rear of the plastic wheel but that did not work. The final design does not have the step but uses the entire width of the wheel. The step is unnecessary.
The OEM bolt should protrude from the rear bearing by about 1/32"
Please post questions.
Bill V

[JPG]

Excellent!

A slight crown would be appropriate.

I assume that 1/32" is the shoulder, not the threads.

[charlese]

Very Very Good!! Keep up the good work.

I disagree with the recommendation for a crown.

Rather than inserting the bolt/axle into the wheel, I suggest a longer bolt. You can have one that just barely clears the closed cover. I'll take a couple of pictures tomorrow. and give you the length measurement that fits my Poly wheel.

Question: Isn't it better to have the bearings on the outside edges of the wheel?

I noticed the tracking on the plastic wheel. I think this outside pressure is a major factor that wears the bushing.

[wa2crk]

JPG
Yes the bolt protrudes by 1/32". As for the crown; I did try that but I could not see a difference between the two. The flat wheel seemed to track better.
Charlese.
It probably would be better to have the bearings at the outer edge of the wheel but I could not find a bolt like that with a stepped 5/16 to 1/4 inch dimension that would do. The bearings have a 5/16 inner bore. You could be right about the bushing wear.
My club members were sanding for about an hour when the problem occurred. (see my post "two on one shopsmith" I ran the present configuration for about an hour at 2000 RPM and the bearings did not even get warm.
Bill V

[JPG]

A 5/16 x 1/4 x ? bushing would allow using a longer 1/4" screw.

[wa2crk]

JPG

I know but I couldn't find one locally
Bill V

[charlese]

Well this came out to be a little more complicated than I remembered.

The screw I used came from McMaster Carr. A 5/16" shoulder x 1 1/2" long shoulder x thread 1/4"-20, head diameter 7/16".

I forgot, but found I used a cut off piece of the SS brass bushing as a spacer on the inside - against the mount. The length of the bushing measures 17/64" or .0261" after sanding down to fit via eyeball. (never measured it before today).

Here is the description as given by the manufacturer - Sunray Inc. :
1.875" X 1.1875" MADE NEW IDLER WHEEL / .8750" STEEL
CORE / INCLUDES (2) 1603-2RS (0.3125" ID) PRECISION
BALL BEARINGS INSTALLED / COVERED IN SMOOTH BLUE
POLYURETHANE TREAD / DUROMETER TO BE
DETERMINED.

The wheel measures 1 7/8" diameter X 1 1/4" width.

The length of the shoulder screw just barely clears the closed case.

Photos:

Tracking

Tracking.JPG (65.64 KiB) Viewed 1234 times

Showing the bushing

showing bushing.JPG (127.38 KiB) Viewed 1234 times

Shows washer on shoulder, shows bearing and steel wheel core

Showing steel core & bearing.JPG (85.08 KiB) Viewed 1234 times

[wa2crk]

Hey charlese.
I did not come up with a number for the McMaster carr bolt. If I did I might have come up with a different solution !!!
Sunray did come up with the same bearings that I used so I guess that their engineers thought that the bearings would support the load as well. I think you posted your cost in another post and I did not want to go that high. Thanks for your post linking part one to part two.
Bill V

[rcplaneguy]

Fantastic job replacing the inferior part with a Shopsmith and wood! (and the ball bearings)