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12 posts 1 2

RPM adjustment

#238999 by dafixer » Sun Sep 10, 2017 6:14 pm

I've got 2 Shopsmiths. One was made in 2004, one in 2005, both are version C headstocks. I just recently took the speed changer out of the '04 to clean and lube it. After getting it back together, it ran smoother than my '05. I was a bit concerned about the RPM's of the '04 after having pulled and re-installed the speed changer because I may have rotated the worm gear to a different position during the cleaning. So, I went to Harbor Freight and bought a CEN TECH non-contact tachometer so I could check the RPM's on the shafts of both machines, just to see how close they were. BOY was I surprised. The '04 has a slow setting RPM of 768 and a fast setting RPM of 5640. But, my '05 has a slow setting RPM of 925 and a fast setting RPM of 6152. My question is this. Has anyone run into an issue with a headstock running as fast as 6k+ RPM? If so, what was your solution to slow it down? I've read the manuals where SS suggests not running the headstock faster than 5200 rpm.
Thanks for your responses!

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Re: RPM adjustment

#239003 by JPG » Sun Sep 10, 2017 6:42 pm

I would perform a 'high speed' adjustment and forget you have a tach.

There are many variables that affect the speed attained at any setting.*

As for the worm gear, it will not affect much of anything. However that assumes the high speed adjustment is done correctly. The critical thing is that the control sheave does not interfere with the speed control parts at 'Fast'(mechanical limit).

For reasonable accuracy of the indicator dial, it must be set to indicate slow/fast at the extremes.

* A reason there is no rpm calibration on the outer dial.

Also belt wear is one of those variables and will affect the result of the high speed adjustment. It will become faster as it wears.

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╟JPG ╢
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Goldie(Bought New SN 377425)/4" jointer/6" beltsander/12" planer/stripsander/bandsaw/powerstation /Scroll saw/Jig saw /Craftsman 10" ras/Craftsman 6" thicknessplaner/ Dayton10"tablesaw(restoredfromneighborstrashpile)/ Mark VII restoration in 'progress'/ 10E(SN E3779) restoration in progress, a 510 on the back burner and a growing pile of items to be eventually returned to useful life. - aka Red Grange

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Re: RPM adjustment

#239012 by dusty » Sun Sep 10, 2017 7:49 pm

The first question that I would like answered is "why does Shopsmith set an upper limit at 5200rpm".

Is there a weak point in the system that makes this prudent? I don't think so.

My two machines read 5942 and 5275 at the high end and 758 and 749 respectively at the low end for whatever that is worth.

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"Making Sawdust Safely"
Dusty

"If one's words are not better than silence, one should keep silent." - Caine
"Strive not to make believers out of naysayers" - Dusty
"Remember that a narcicist can be taught nothing".

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Re: RPM adjustment

#239014 by JPG » Sun Sep 10, 2017 8:13 pm

dusty wrote:The first question that I would like answered is "why does Shopsmith set an upper limit at 5200rpm".

Is there a weak point in the system that makes this prudent? I don't think so.

My two machines read 5942 and 5275 at the high end and 758 and 749 respectively at the low end for whatever that is worth.


I believe the 5200 is a nominal design number that establishes the reference from which all other nominal settings are based. It assumes motor load/rpm as well as pulley positioning and tolerances, belt dimensions(both length, width, and amount 'squeezed') and speed control assembly . . .

Nominal is theoretical, not real nor measurable.

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╔═══╗
╟JPG ╢
╚═══╝

Goldie(Bought New SN 377425)/4" jointer/6" beltsander/12" planer/stripsander/bandsaw/powerstation /Scroll saw/Jig saw /Craftsman 10" ras/Craftsman 6" thicknessplaner/ Dayton10"tablesaw(restoredfromneighborstrashpile)/ Mark VII restoration in 'progress'/ 10E(SN E3779) restoration in progress, a 510 on the back burner and a growing pile of items to be eventually returned to useful life. - aka Red Grange

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Re: RPM adjustment

#239015 by everettdavis » Sun Sep 10, 2017 9:08 pm

The Power Pro has far higher speeds but the weaker control sheave with small button bearing to quadrant interface goes away.

Everything else including the new drive sleeve assembly for DVR drive are much the same as a traditional headstock.

My best guess

Everett

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Re: RPM adjustment

#239016 by JPG » Sun Sep 10, 2017 9:29 pm

everettdavis wrote:The Power Pro has far higher speeds but the weaker control sheave with small button bearing to quadrant interface goes away.

Everything else including the new drive sleeve assembly for DVR drive are much the same as a traditional headstock.

My best guess

Everett


Good Point! The idler shaft(and that 'small' bearing) is 1.6X as fast as the quill shaft.

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╔═══╗
╟JPG ╢
╚═══╝

Goldie(Bought New SN 377425)/4" jointer/6" beltsander/12" planer/stripsander/bandsaw/powerstation /Scroll saw/Jig saw /Craftsman 10" ras/Craftsman 6" thicknessplaner/ Dayton10"tablesaw(restoredfromneighborstrashpile)/ Mark VII restoration in 'progress'/ 10E(SN E3779) restoration in progress, a 510 on the back burner and a growing pile of items to be eventually returned to useful life. - aka Red Grange

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Re: RPM adjustment

#239049 by dafixer » Mon Sep 11, 2017 4:09 pm

Tell me more about this "high speed" adjustment procedure...

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Re: RPM adjustment

#239051 by reible » Mon Sep 11, 2017 4:28 pm

dafixer wrote:Tell me more about this "high speed" adjustment procedure...


Here is a good place for information like this:

http://www.songofthegreatlakes.com/sshighspeed.htm

Ed

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{Knight of the Shopsmith} [Hero's don't wear capes, they wear dog tags]

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Re: RPM adjustment

#239113 by dafixer » Tue Sep 12, 2017 9:44 pm

Nice. Thank you very much.

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Re: RPM adjustment

#239129 by terrydowning » Wed Sep 13, 2017 10:02 am

reible wrote:
dafixer wrote:Tell me more about this "high speed" adjustment procedure...


Here is a good place for information like this:

http://www.songofthegreatlakes.com/sshighspeed.htm

Ed

Thanks, that's a favorite now!

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