New Wheels for Power Stands or Pro Planer

[dusty]

OK, I'm just going to start punching keys and see what comes out... I may be trying to remember from way back maybe into the old email list days but I have already forgotten today's lunch.
There is a notion in my head that at some point somebody once said that the top of the caster stem was to be a small area (like a dome) and the little cylinder (piston) bore was to be a flat bottom. I think that it was supposed to be like that so that the contact area would be quite small to allow the caster to caster easier than if the caster stem made full flat contact at the top of the stem. I believe the same thing applies if the stem is too short and the cylinder sits tight against the top of the wheel yoke. Even with a washer between the caster and the base of the cylinder that adds contact area and so adds friction to the swiveling of the caster. I know that the cylinder "can" swivel in the casting but that is a hard steel against a soft aluminum casting which is pretty much the technical definition of a brake.
I'm kind of fond of casters that swivel on a ring of ball bearings above the wheel rather than in the stem but they also can have problems if the bearings fill up with sawdust. Nothing worse than a caster that does not want to caster.
What I "think" I remember was someone trimming the stem a tiny bit if needed (dimensions to be determined at the time) and inserting a single, drop in fit, very hard steel ball bearing ball so that all weight swiveled on the tiny contact areas of the hard ball.
I hope that makes sense... Did I just hear 37 people throw their mouse and run screaming from the room?


.

It all makes sense and it fits the discussion. The stem on the 2" casters that I have are domed while the top end of the stem on the 3" caster is flat. However, the 3" caster swivels on a ball bearing that is shrouded by a ring (dust cover) over the top of the bearing. Since the stem of the 2" caster is longer than the bore in the plunger it is reasonable to conclude that the 2" caster swivels on the dome.

This all certainly explains why the 3" casters swivel so much better. Add to that the sealed bearings in the wheels of the 3" casters and we know why the caster upgrade is so well received.

[jsburger]

I don't know what the ProPlaner weights but I don't believe it is heavier than a Mark V but if it is it is not enough to make a significant difference in caster fatique. It is not the wheels that have failed. It is the metal part that wraps over the top of the wheel (the part that has holes for the axles).

The price for Shopsmith casters is not out of line.

There is a little slop in the mounting holes but not enough to facilitate "adjustment".

There is enough room to redrill holes per the 3" instruction sheet but the support members that form the shelf above the whels would likely interfer with the pedal travel. Not worth the risk.

I am going to order the previously mentioned 2" casters for a test. I am sure that they will work. Swivel radius being the critical criteria these swivel in a smaller radius than do the Shopsmith casters. If these don't work on the ProPlaner I'll have $40 worth of casters to use elsewhere.

Report to follow in a week or so.

The Pro Planer did not come with a shelf. At least mine bought new did not. Those were/are simply leg braces. I don't think there is any reason they could not be moved up a little for clearance if need be.

[jsburger]

I am assuming the SS caster in your pix was of fairly recent vintage.

Older casters have a 'ball' end.

The piston bore has a corresponding round shaped bottom.

The Mark VII pistons have a bad trait of cracking/splitting.

I consider that to be the result the caster protruding out of the lower end on the piston as shown in your pix.

So if the stem is shorter, the washer fix makes sense.(lowers the wheel)

Since the 'current' casters do not have the ball end(at least they do not look so in the pix), I think a shorter stem is preferred.

I be describing older pistons above re the bore end.

I am amazed the planer casters have stems that are too long. I suspect the same cause as some deficient motor belts a while back.

We gotta be careful here. I can not swear that these are Shopsmith casters. They may be some that I purchased from a different source. What I have shown and commented on are simple "the casters that have been installed on my ProPlaner" for a very long time.

Unfortunately, I cannot check the casters on my other SPT because they are all packed away in a POD.

If the consensus is that casters with 1/4" shorter stem will work I plan to order some of the alternate casters.

I wonder about that too. I have never seen SS 2" castors with red wheels. Anyhow here is a picture of my pro planer castor. The planer is on the floor but the castor is tight vertically so it is bottomed out in the piston. I have 7 sets of castors installed and they all look the same. The only ones that are different are the ones where the wheel is not tight to the floor. There is about 1/16" vertical play so they show a bit more stem.

[reible]

The reason I mentioned the slop is that when I put my router table together it did not have casters so when I got the caster set and brackets I had to do a few adjustments (per the caster instructions) with braces and loosening fasteners to get the casters and brackets to fit. There seemed to be a lot of slop to play with.

Ed

[dusty]

I don't know what the ProPlaner weights but I don't believe it is heavier than a Mark V but if it is it is not enough to make a significant difference in caster fatique. It is not the wheels that have failed. It is the metal part that wraps over the top of the wheel (the part that has holes for the axles).

The price for Shopsmith casters is not out of line.

There is a little slop in the mounting holes but not enough to facilitate "adjustment".

There is enough room to redrill holes per the 3" instruction sheet but the support members that form the shelf above the whels would likely interfer with the pedal travel. Not worth the risk.

I am going to order the previously mentioned 2" casters for a test. I am sure that they will work. Swivel radius being the critical criteria these swivel in a smaller radius than do the Shopsmith casters. If these don't work on the ProPlaner I'll have $40 worth of casters to use elsewhere.

Report to follow in a week or so.

The Pro Planer did not come with a shelf. At least mine bought new did not. Those were/are simply leg braces. I don't think there is any reason they could not be moved up a little for clearance if need be.

Yes, mine did not come with a shelf either. I spoke improperly of a shelf when I was really speaking of the leg braces that support the shelf I added.

[dusty]

Maybe my comments are confusing. I did not mean to say the stems on the 2" casters are too long. If I have not made any errors in my measurements, the bore in the plunger and the stem length are the same (1 7/8"). But there is a 1/4" gap, as seen in mine and Johns photo images, between the wheel yoke and the bottom of the plunger.

Why the gap. It seems to me as though the stem should bottom in the bore and thus bury the stem within the bore.

While pondering that keep in mind that the stems on the 3" casters are 7/16" shorter and they are nearly buried in the plunger.

The grip rings on both the 2" and 3" casters are located the same distance from the ends of the stems (about 1/4").

Shopsmith Plunger and Caster Stem.png (99.01 KiB) Viewed 4621 times

I so wish Shopsmith published detailed mechanical drawings.

[jsburger]

Maybe my comments are confusing. I did not mean to say the stems on the 2" casters are too long. If I have not made any errors in my measurements, the bore in the plunger and the stem length are the same (1 7/8"). But there is a 1/4" gap, as seen in mine and Johns photo images, between the wheel yoke and the bottom of the plunger.

Why the gap. It seems to me as though the stem should bottom in the bore and thus bury the stem within the bore.

While pondering that keep in mind that the stems on the 3" casters are 7/16" shorter and they are nearly buried in the plunger.

The grip rings on both the 2" and 3" casters are located the same distance from the ends of the stems (about 1/4").

Shopsmith Plunger and Caster Stem.png

I so wish Shopsmith published detailed mechanical drawings.

It seems to me that the reason is this. The swivel point on the 2" castors is the domed end of the stem on the bottom of the piston bore as JPG mentioned. With the new castors the swivel point is the ball bearing race on the castor so you want the stem to be shorter than the piston bore to allow the weight to be carried by the piston on the ball bearing race of the castor wheel. Even the 10ER steel castors have a rounded end on the stem.

[JPG]

OK, I'm just going to start punching keys and see what comes out... I may be trying to remember from way back maybe into the old email list days but I have already forgotten today's lunch.
There is a notion in my head that at some point somebody once said that the top of the caster stem was to be a small area (like a dome) and the little cylinder (piston) bore was to be a flat bottom. I think that it was supposed to be like that so that the contact area would be quite small to allow the caster to caster easier than if the caster stem made full flat contact at the top of the stem. I believe the same thing applies if the stem is too short and the cylinder sits tight against the top of the wheel yoke. Even with a washer between the caster and the base of the cylinder that adds contact area and so adds friction to the swiveling of the caster. I know that the cylinder "can" swivel in the casting but that is a hard steel against a soft aluminum casting which is pretty much the technical definition of a brake.
I'm kind of fond of casters that swivel on a ring of ball bearings above the wheel rather than in the stem but they also can have problems if the bearings fill up with sawdust. Nothing worse than a caster that does not want to caster.
What I "think" I remember was someone trimming the stem a tiny bit if needed (dimensions to be determined at the time) and inserting a single, drop in fit, very hard steel ball bearing ball so that all weight swiveled on the tiny contact areas of the hard ball.
I hope that makes sense... Did I just hear 37 people throw their mouse and run screaming from the room?


.

Where did '37' come from.

That all makes sense to me but I swear the bore is not flat bottomed.

If I get an opportunity I will peruse some of my casters and pistons.

[dusty]

The stems on my 2" casters are ball shaped.

What the end of the bore looks like, I don't know.

It doesn't seem to matter though because it seems that the stems do not reach the bottom of the bore. They would IF the caster went all the way in. Looking at Johns' picture and at mine it can be seem that they don't. There is about a 1/4" gap. This is what my sketchup was intended to show.

[JPG]

The stems on my 2" casters are ball shaped.

What the end of the bore looks like, I don't know.

It doesn't seem to matter though because it seems that the stems do not reach the bottom of the bore. They would IF the caster went all the way in. Looking at Johns' picture and at mine it can be seem that they don't. There is about a 1/4" gap. This is what my sketchup was intended to show.

Well now if they do not 'go all the way in', what is stopping them?