Shopsmith Question

robinson46176 · Post by **robinson46176** » Sat Feb 25, 2012 9:55 am

dusty wrote:Do the reverse and forward keys connect to relays that actually do the power switching OR is the power switching accomplished by the switches.

I really wonder why this feature was abandoned in the transition to the early Mark 5? I never read about owners having power switching problems which leads me to conclude that it was not a reliability/dependability issue.

Now, think about it. If they had carried that reversibility feature through, half of the PowerPro's thunder would be lost.

It also seems curious to me that of the three motor manufacturers, Emerson's is the only one that is not reversible. They had to design in the non-reversible feature.

I have said before that they started back up again with the wrong one... Then again we have no idea of a possible half zillion other factors. Cost was probably the killer. I'm sure that a lot was the pent up demand for parts for all of those orphaned Mark V's and the nostalgia connected to them as well as the stigma of the 2 Mark VII minor problem spots. I say minor because if you could just order a new plastic cam for $4 or $5 melting one wouldn't amount to a hill of beans.

I'll see if I can get a picture of the backside of the switch. You can see in the picture a clear spot in the 2 outside buttons. Inside of the case behind the switch there are 2 tiny light bulbs mounted that makes which ever of the 2 buttons is pushed in glow. They do not work on mine and I do not really care.

They really did intend for the Mark VII to be a "super" Shopsmith...

On an added note, IIRC the Mark VII only uses 5' of floor space instead of 6'.

.

JPG · Post by **JPG** » Sat Feb 25, 2012 9:59 am

dusty wrote:Do the reverse and forward keys connect to relays that actually do the power switching OR is the power switching accomplished by the switches.

I really wonder why this feature was abandoned in the transition to the early Mark 5? I never read about owners having power switching problems which leads me to conclude that it was not a reliability/dependability issue.

Now, think about it. If they had carried that reversibility feature through, half of the PowerPro's thunder would be lost.

It also seems curious to me that of the three motor manufacturers, Emerson's is the only one that is not reversible. They had to design in the non-reversible feature.

The mark VII was introduced in 1963 after the Magna American Goldies. Rather than being 'abandoned', it was introduced with the MVII.

The switch does all the switching, but it does have a start relay instead of a centrifugal switch.

The switch is a crucial maintenance problem and a replacement not available.

I do not think the Emerson was designed with the intention of preventing later conversion to being reversible. I think it was merely a build process decision. I do not think the other motor vendors considered potential user modifications either.

JPG · Post by **JPG** » Sat Feb 25, 2012 10:11 am

A little light Saturday morning reading!:rolleyes:

https://forum.shopsmith.com/viewtopic.php?t=6983&page=3

FWIW post 11 accurately describes the induced EMF picking the start relay when it runs.

camerio · Post by **camerio** » Sat Feb 25, 2012 11:10 am

Thank your JPG for answering my question and mine is a B with the holes in the ears :

"Later " B" castings have holes in the ears to allow locking the switch off"

What could be use to block it, not that I need to do so but just asking.

Culprit · Post by **Culprit** » Sat Feb 25, 2012 3:40 pm