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How can idler sheave be removed?
Posted: Sun Apr 22, 2012 10:20 pm
by scuba-geek
Hi everyone,
I have been reading this forum for several months now. I can usually find the answers I am looking for in other posts, so this is my first post.
I have a 1980 model 500. I have rebuilt just about everything in the headstock, except the idler. So, I purchased a new idler shaft and bearing. Now I am trying to remove the sheave to install it on the new shaft. I removed the U shaped reataining clip, but the sheave will not move.
Is there something I am missing?
Is there a trick to removing this sheave?
Should I have purchased the idler with the sheave already attached?
Thanks,
Rob
Posted: Mon Apr 23, 2012 9:33 am
by peterm
Sorry, thought I had an answer but on closer reading of your query, realized I misunderstood.
But, some photos in this post might help some:
https://forum.shopsmith.com/viewtopic.php?t=5891
Posted: Mon Apr 23, 2012 11:36 am
by scuba-geek
Hi,
My problem is pretty simple, the idler sheave is stuck on the old idler shaft. How do I get it off with damaging it?
Here is a picture of the parts I am working with.
Thanks,
Rob
Posted: Mon Apr 23, 2012 12:15 pm
by dusty
scuba-geek wrote:Hi,
My problem is pretty simple, the idler sheave is stuck on the old idler shaft. How do I get it off with damaging it?
Here is a picture of the parts I am working with.
Thanks,
Rob
It is amazing just how much communication improves with a simple photograph. There is an additional clip that retains the sheave in place on the shaft.
[ATTACH]17274[/ATTACH]
[ATTACH]17275[/ATTACH]
It is hidden down inside the sheave. It would not take much sawdust to conceal it from view.
Posted: Mon Apr 23, 2012 12:35 pm
by scuba-geek
Hi Dusty,
Are you saying I need to remove the round retaining ring before the sheave can slide off the idler shaft?
I cleaned out the gap between the bearing and the sheave, but I cannot see the retaining ring.
Thanks,
Rob

Posted: Mon Apr 23, 2012 1:30 pm
by tunznath
Hi Just looking at the picture - I have a mark 5 that I got from the PO. and the motor was changed to 220 v- thats what we have here - i was doing maintenance and noticed the key way - (the sliding metal thing in the groove on the shaft looks like it tapers at the area where the round depression is - on mine it is the same width all the way and it also rocks slightly if pressure is applied toward the groove in the shaft ( could it have been installed backwards? and upside down?)- I have a problem with the speed control being stiff when it engages the keyway it happens as the keyway is touched by the other sheave- is it supposed to be oriented like this and is there a taper on the leading edge of the keyway - sorry to hijack thread
thasnks
nath
Posted: Sun Jun 10, 2012 8:47 pm
by tunznath
bump please
Stuck idler sheave / key
Posted: Sun Jun 10, 2012 10:20 pm
by JPG
The idler sheave normally does not move on the idler shaft so it is prone to getting stuck/gummed up. Liberal application of a penetrating oil
(K1:D) and subsequent hard pulling after soaking should get it off. By removing the u clip(copper colored in yer pix) you have removed all that is holding the sheave on the shaft other than the gunk etc.
Be careful to not bend/deform the sheave when 'pulling'. Sometimes
gentle tapping
around the sheave will get it started.
Another way - by supporting the sheave and 'hammering' the shaft(you are
replacing the shaft). I like to support such stubborn things with my hand while 'hammering'. Hand giving under impact prevents part being held from deforming.
The key has a bend at the end that is inserted in a depression machined into the shaft. The sheave holds the key in that depression and the bend prevents the key from sliding out. The key should lay flat in the bottom of the slot. If it sticks out away from the slot at the control sheave end, it is probably bent(perhaps the result of trying to remove it by prying). Burrs on either the key or the slot in the bore of the idler sheave can create binding.
Bump? Leave it alone!

Posted: Mon Jun 11, 2012 3:15 pm
by dusty
No one responded to this post. I certainly hope that you were able to resolve your problem, Rob.
With that copper colored clip removed, you should be able to remove the shaft from the Idler Sheave almost as easily as you did the Control Sheave.
It is amazing, however, how a very small burr can jam things up.
The problem that you face in this position is doing damage to the sheave.
I would try wedging something between the bearing on the idler shaft and the sheave. If you can move the sheave at all, you'll be able to get it off.
Again, I apologize for this post going without response for over two months.
Posted: Tue Jun 12, 2012 11:04 am
by scuba-geek
Hi Dusty,
Thanks for your replay and sorry I did not post a followup.
I got the sheave off with no damage.
I drilled a pieace of wood to make a hammering caul and I was able to get it off. I am up and running with the new idler bearing.
Much quieter now.
Thanks