New Wheels for Power Stands or Pro Planer

[JPG]

John, you have not likely seen Mark VII pistons that are cracked/broken off. The walls are thinner on those pistons. The stems are also shorter so any side load is transferred to the end of the piston(outward force). That is 'worse' than the M5/V, but I think it is undesirable there as well. With some(maybe all) of the vertical load being taken up by a direct contact of the piston to the caster frame/top bearing, I think the sideways loading will be less likely to cause deformation of anything.

Take a look at Mod 10 casters. The pistons also have thin walls(compared to M5/V), but the piston to caster clearance is very small(almost to actually touching).

This maybe a lot of consternation for little cause.

I do think the bent frames/crooked stems are the result of other forces at work.

[dusty]

Two questions. I might have missed this.
1. Has anyone checked that the bore depths are a uniform depth in the cylinders?
2. Has anyone ran a drill bit that size in those bores to be sure that the stems are actually bottoming out all of the way in?
OK, three.
3. Do we really know if the bores are uniformly flat bottomed? Or are some at common drill bit angles?
Bonus question... Has anyone ran a drill bit that size (maybe flat bottomed) down in that bore to be sure that there is nothing stopping the stem too soon? OK, that is a repeat of #2 but I think it is important.


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The bottom of the bores has a spherical cross section. i.e. a domed stem mates to a rounded bottom. This can be indirectly observed by feeling a probe traverse from the outer to center of the bore. With a good light(and eyes) it can be observed directly.

This indicates to me that the small protrusion is intentional(the stems are intended to bottom out in the bore with a slight clearance between the piston and shoulder on the caster frame).

I think that is not desirable from a durability standpoint.

I think the damaged casters previously pictured are the result of the casters encountering an immovable object(step/hole in the floor).

The sides of the bore are smooth all the way to the bottom. The friction ring is just that - friction grip only, no groove in the bore ...

First I am not sure I agree with that but whatever.

I agree with everything else you have said. The SS castors, actually the piston was designed that way from the very beginning 70+ years ago. I don't understand all the angst and hand wringing abut a 1/8" or less exposure of the castor stem below the piston. The piston was designed so the load is carried on the end of the stem. Presumably because the steel of the stem and the piston is harder than the metal the yoke for the wheel is made of. Why would you want the weight of the machine sitting on the castor yoke and wearing it away every time the castor wheel swivels?

Dusty's new castors have a ball bearing on top of the wheel yoke. If the castor stem does not go all the way in so the weight of the machine sits on that ball bearing what is the point of the ball bearing?

That is the point. With the new casters, the contact point between the machine and the casters is the bottom of the plunger and the top of the caster yoke (the shroud over the top of the bearing).

[jsburger]

John, you have not likely seen Mark VII pistons that are cracked/broken off. The walls are thinner on those pistons. The stems are also shorter so any side load is transferred to the end of the piston(outward force). That is 'worse' than the M5/V, but I think it is undesirable there as well. With some(maybe all) of the vertical load being taken up by a direct contact of the piston to the caster frame/top bearing, I think the sideways loading will be less likely to cause deformation of anything.

Take a look at Mod 10 casters. The pistons also have thin walls(compared to M5/V), but the piston to caster clearance is very small(almost to actually touching).

This maybe a lot of consternation for little cause.

I do think the bent frames/crooked stems are the result of other forces at work.

No I have not. However, if you change a proven design you get what you get. I guess they should have been left alone.

If you do that without a bearing on the top of the castor frame like the SS castor I think the harder (presumably) metal of the piston will ware out the castor frame in short order.

I agree that Dysty's replacements are likely a better castor than the SS originals but after 70 years of a proven design I am not going to run out and change all the wheels on the 6 sets of castors I have in use.

The picture is a set of 60+ year old 10ER castors that have just about the same extension as the 6 sets of my MK V castors. None of them are deformed and only 2 of my MK V sets were bought new by me. The other 4 sets came from eBay with an unknown history.

[JPG]

John, it is the position of the caster/piston when bearing a load that counts. I am not sure your pix were in that condition.

Oh I completely agree that without 'top swivel bearings', bearing on the caster frame/(whatever that step is) is undesirable. What I consider undesirable with the Mark 5/V casters is the size of the gap.

An additional deviation of the MVII is the pistons slide in a stamped part rather that bored holes(sloppy fit).

[jsburger]

John, it is the position of the caster/piston when bearing a load that counts. I am not sure your pix were in that condition.

Oh I completely agree that without 'top swivel bearings', bearing on the caster frame/(whatever that step is) is undesirable. What I consider undesirable with the Mark 5/V casters is the size of the gap.

An additional deviation of the MVII is the pistons slide in a stamped part rather that bored holes(sloppy fit).

OK but, I am not sure how I could get them in all the same without trying without them being bottomed out. Those pictures were taken in Sep 2015.

I will take pictures tomorrow of those castors mounted on the machine with weight on them. Then we shall see.

I agree that if the gap is "excessive" then there could be a problem. I do not consider a 1/8" gap excessive. How much of a gap do you consider excessive without touching?

[JPG]

Anything that causes damage to the caster!

I think 1/32" (0.031") is a moderate objective. My 10E casters have much less clearance.

But let us not be blinded to the likelihood that other forces are causing damage(I think your point as well).

[dusty]

Thank you, John. I now understand why we experience the differences in caster sets as we do. Your casters do truly insert deeper into the plunger. Those that you pictured were have a very minimal gap and I think that gap is intentional so as to reduce friction when the casters swivel.

BUT, we have not been comparing apples with apples. Your pictured caster set appears to be one of those that has not changed at all mover the last 70 years. It is not a modern day Retractable Caster Set 555354. A "functional equivalent" but with significant design differences.

The wheels are different too.

[reible]

After cleaning up a bit in the shop yesterday evening I got down to try and measure the "gap" I see. Decided to use the measuring bars I have. With weight on an eight inch was to large, but not by much. Guess at 3/32??

As I mentioned I have not seen mine get bent. I also don't have seams I roll across in the garage. How ever the drive way is really ruff, maybe a very different load on the wheels and stems.

So have all of your own casters fit the same way with what looks like a large amount of stem showing? If so one might question if it is a caster issue of the other part they fit in..... Just wondering.

Ed

[robinson46176]

I picked up a set of 2" casters at Menard's Friday just to try them. They are the gray rubber wheeled with ball bearing swivel (listed as "friction stem"). The stem is about 1/4" shorter than the SS casters. $3.78 each.
I'll try this set on my 510 and see if I like them. I got kind of annoyed the last time I moved it, I wanted to turn and it only wanted to go straight... I hate all of the yelling that brings on. I will not oil the ball bearings but I will puff a little graphite into them.
If I like the casters I'll pick up a set sometime for the Push-me Pull-me double drill press. The 510 is the one I re-position fairly often and so is the drill press. The other SS's, not so much.
On a side note I love the caster and lift system on my Ridgid TS-3650 table saw. Just push the pedal down once till it clicks and it is up and ready to move easily.

BTW, I didn't make a special trip, I was picking up 25 common 8" concrete blocks. Their blocks are decent quality and the generic 8"x8"x16" are currently .89 cents each.


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[dusty]

John, it is the position of the caster/piston when bearing a load that counts. I am not sure your pix were in that condition.

Oh I completely agree that without 'top swivel bearings', bearing on the caster frame/(whatever that step is) is undesirable. What I consider undesirable with the Mark 5/V casters is the size of the gap.

An additional deviation of the MVII is the pistons slide in a stamped part rather that bored holes(sloppy fit).

OK but, I am not sure how I could get them in all the same without trying without them being bottomed out. Those pictures were taken in Sep 2015.

I will take pictures tomorrow of those castors mounted on the machine with weight on them. Then we shall see.

I agree that if the gap is "excessive" then there could be a problem. I do not consider a 1/8" gap excessive. How much of a gap do you consider excessive without touching?

Please, when you do this photo op include a Shopsmith Caster Assembly other than the one shown previously.

The gap on mine is 3/16".

Caster Stem Gap 2.18.18.jpg (49.45 KiB) Viewed 4747 times