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3" caster upgrade

Posted: Wed Jan 11, 2023 11:10 am
by dusty
Can I drill the legs according to the dimensions detailed on the template OR should I make some adjustments.

If anyone has used the template and not been satisfied with the results, please let me know. I don't want to do this wrong.

Re: 3" caster upgrade

Posted: Wed Jan 11, 2023 12:46 pm
by JPG
IIRC the early "template" had dimensional inaccuracies.

Re: 3" caster upgrade

Posted: Wed Jan 11, 2023 1:31 pm
by chapmanruss
There have been other threads on this subject and opinions vary. Some like to deviate slightly while other like myself have been happy with using the recommended distances. I used the Metal Drilling Guide that came with the Caster Upgrade as opposed to the paper template. This has my casters slightly off the floor when retracted. As for JPG's comment,
IIRC the early "template" had dimensional inaccuracies.
I believe there was discussion about that. The paper template that came with my upgrade is Rev. D dated 05-12. The Metal Drilling Guide I have matches that paper template.

There is another consideration when adding the 3" Caster Upgrade to a Mark 5/V. Older Retractable Caster assemblies had the Foot Pedal closer to the Cam on the Rod which can cause inference with the 3" casters rotating. Newer Retractable Caster assemblies have about 2" between the Foot Pedal and the Cam. The pictures below show the differences between the older and newer Retractable Caster Assemblies.

Below is the older assembly.

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Retractable Casters - Mark 5.jpg
Retractable Casters - Mark 5.jpg (222.75 KiB) Viewed 5281 times
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Below is the newer assembly.

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Retractable Casters - Mark V.jpg
Retractable Casters - Mark V.jpg (116.91 KiB) Viewed 5281 times
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Notice the spacing difference between the foot pedal and the cam.

Re: 3" caster upgrade

Posted: Wed Jan 11, 2023 1:44 pm
by dusty
If you have the drill template (or a set of holes drilled using the template) can you tell me what the offset distance is between the old and the new holes? I believe it to be 1 9/16". but am considering a slight increase so as to get the wheels a bit more off the floor).

Re: 3" caster upgrade

Posted: Wed Jan 11, 2023 4:05 pm
by jsburger
JPG wrote: Wed Jan 11, 2023 12:46 pm IIRC the early "template" had dimensional inaccuracies.
I had a discussion about this with Mike Young years ago. The original paper templates were correct. At some point they started reproducing them on an in house copy machine. That changed the size of the templet making the dimensions incorrect. The correction was the metal templet.

Re: 3" caster upgrade

Posted: Wed Jan 11, 2023 4:13 pm
by JPG
My belief is that it is NOT necessary to "get the wheels off the floor". It is only necessary to get the weight off the casters. There is play in the stem/ring/piston fit that allows the weight to be off the casters while the casters are still in contact with the floor and the legs bearing against the floor.

This casters still on the floor when SS is lowered to the floor situation allows for maximum lift when the SS is raised. About 1/4" and about 1/2" is the design goal for the two raised positions. I do not think that is attainable IF the casters clear the floor when the SS is lowered to the floor.

So if thy casters are clearing the floor with the 1 9/16" difference I would consider decreasing that somewhat so as to drop the casters to the floor when the SS is lowered. Another consideration is to decrease the hole size to 17/64".

And yes the copier inadvertent dimensional tweeking scenario is my understanding as well.

Now WHAT is the metal template offset result?

Re: 3" caster upgrade

Posted: Wed Jan 11, 2023 4:52 pm
by RFGuy
JPG wrote: Wed Jan 11, 2023 4:13 pm My belief is that it is NOT necessary to "get the wheels off the floor". It is only necessary to get the weight off the casters. There is play in the stem/ring/piston fit that allows the weight to be off the casters while the casters are still in contact with the floor and the legs bearing against the floor.
JPG,

I think you raise (pun intended) an important point. Mine are just kissing the floor but not bearing any weight when lowered. I have a garage shop which inevitably has the expansion joints in the concrete floor. Moving my SS across the expansion joint dip is always a pain, but less so with the 3" casters than the original ones. I bought the premium casters a few years ago. I can't remember if the metal template jig from SS came with the order or if I paid extra for it. My Dad upgraded his 510 casters after me and didn't get the jig from SS so I gave it to him afterwards - he is on the other side of the country so I can't easily get it back from him. Otherwise I would loan my jig to Dusty. It really is easy to do the install with the SS jig. Bottomline, is I think you want the Mark V to raise as much as possible when in the up position unless you have a perfectly flat floor.

Re: 3" caster upgrade

Posted: Wed Jan 11, 2023 5:01 pm
by JPG
I am glad to hear the metal template created the floor kissing result which allows greater clearance when 'up'. Hopefully thine is not an aberration.

Re: 3" caster upgrade

Posted: Wed Jan 11, 2023 5:41 pm
by dusty
Russ

I have the same template (Rev D) so I am going to drill in accordance with that.

Thank you for the response.

Re: 3" caster upgrade

Posted: Wed Jan 11, 2023 6:22 pm
by JPG
Again, WHAT is the offset?