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Shopsmith Mark 5.7 project
Posted: Sat Apr 11, 2020 7:06 pm
by FissionChips
Hello, forum!
I'm fairly new to the Shopsmith world. In the past year I've bought a working Mark V that was missing a bunch of stuff and a Mark VII (60's) that has most of its parts, but the motor hums when I try to turn it on but will run when I push turn it.
I'm thinking about putting the Mark V headstock on the Mark VII body (Mark 5.7? Sounds better than mark V.VII) and parting out the Mark VII headstock/plastic rack.
I have two main questions right now, and I'll probably have more later:
-I know I'll be losing the reverse function, but I can't imagine ever needing it. Are there other considerations I should make before putting these two together?
-Someone has already expressed interest in some of the Mark VII headstock parts and I don't want to ask a ridiculous amount for them. Is there a place I can find reasonable prices for them? I can find a few in Ebay's completed sales, but not all of them. I'm not looking to make a profit, but I'm also not looking to take a loss and I want to offer them at a fair price.
Thanks in advance!
Re: Shopsmith Mark 5.7 project
Posted: Sat Apr 11, 2020 7:30 pm
by jsburger
The MK VII motor should be an easy fix if it runs when spun by hand. It is either the start capacitor or the start relay/centrifugal switch. Start capacitor is the likely culprit and easy and cheap to replace. They don't very often go bad but sometimes.
Re: Shopsmith Mark 5.7 project
Posted: Sat Apr 11, 2020 7:36 pm
by FissionChips
jsburger wrote:The MK VII motor should be an easy fix if it runs when spun by hand. It is either the start capacitor or the start relay/centrifugal switch. Start capacitor is the likely culprit and easy and cheap to replace. They don't very often go bad but sometimes.
I was thinking similar, but I couldn't find a test procedure for either of them. I think it's an internal relay because I didn't see one mounted outside. I spent a good amount of time this week blasting compressed air through the motor with no success.
Re: Shopsmith Mark 5.7 project
Posted: Sat Apr 11, 2020 7:43 pm
by jsburger
FissionChips wrote:jsburger wrote:The MK VII motor should be an easy fix if it runs when spun by hand. It is either the start capacitor or the start relay/centrifugal switch. Start capacitor is the likely culprit and easy and cheap to replace. They don't very often go bad but sometimes.
I was thinking similar, but I couldn't find a test procedure for either of them. I think it's an internal relay because I didn't see one mounted outside. I spent a good amount of time this week blasting compressed air through the motor with no success.
I believe it has a relay. JPG will chime in and confirm. Regardless if the capacitor is bad it won't run. The fact that you can spin it up by hand and it runs points to the capacitor.
I would replace the capacitor and see what happens. They are cheap and easy to replace. If it doesn't fix the problem you are not out much and when you get it fixed you have a new capacitor. Not a bad thing given the age. I have 5 10ER's here from the '50s and they all run fine but you never know.
Re: Shopsmith Mark 5.7 project
Posted: Sat Apr 11, 2020 8:48 pm
by JPG
Ding Dong.
Some MVII had motors with external start relay, others had internal start switch.
The most likely culprit is the power/direction switch.
The switch can be removed from the discussion by bypassing that direction switching.
The switch terminals are labeled [2], [5](twice), [T5], and [T9]. Leave [L1] and [L2] wires alone.
Before moving any wires, document where the wires are currently going on the switch.
Ignoring wire colors(since they vary with motor brand), connect the wire going to [5] to the wire going to [T9](after removing them from the switch). The short jumper between the two [5] terminals can be left there.
Connect the wire going to [2] to the wire going to [T5](again after removing them from the switch).
Assuming the internal start switch and start capacitor is AOK,the motor should start when turned on. IF it runs backwards, reverse the [2] and [5] wires.
OVER.
Re: Shopsmith Mark 5.7 project
Posted: Sat Apr 11, 2020 11:13 pm
by lahola1
The only things you gain by mounting the mkV headstock on the mkVII base is easier lifting vertical into drill press mode; plus using parts you already have and making money selling mkVII parts.
The advantages I have found in the mkVII:
as I have said; easier lifting because of the base design.
With the reverse motor:
under table routing and shaping, I have used this more than over table routing.
reverse sanding on the lathe.
I can mount my jointer on the left side; then move the headstock to the right side; run in reverse connected to my bandsaw.
And headstock movement with the plastic rack; I wouldn't trade this for the world!
Now the disadvantages I've found:
It's hard to make fine vertical adjustments on the table with the small crank.
I always turn the speed back to slow and start slow for fear of damaging the almost irreplaceable motor.
And other irreplaceable parts like the speed control.
As far as what mkVII parts should sell for: I have no idea. I would sell them on Ebay; auction mode. I'm sure you would get a fair price but I would think about it first before you tear it apart; try and get the motor running.
I have a mkV sitting in my barn I don't use because I have a mkVII.
Re: Shopsmith Mark 5.7 project
Posted: Sat Apr 11, 2020 11:26 pm
by FissionChips
Hi JPG!
Thanks for the insight! I did that and it fired right up! I had to press the FWD button on the switch for it to turn on, so I'm not sure I understand what I just did...I took the switch out of the circuit, but still needed it to press it to turn the motor on? Sorry if I'm misunderstanding.
Thanks for your help!
Re: Shopsmith Mark 5.7 project
Posted: Sat Apr 11, 2020 11:44 pm
by FissionChips
Thanks lahola1. I didn't realize the under table routing required the reverse function. I might have to rethink parting it out...using JPG's suggestion it fired right up and sounded wonderfully smooth...much smoother than my Mark V!
Re: Shopsmith Mark 5.7 project
Posted: Sun Apr 12, 2020 12:24 pm
by JPG
FissionChips wrote:Hi JPG!
Thanks for the insight! I did that and it fired right up! I had to press the FWD button on the switch for it to turn on, so I'm not sure I understand what I just did...I took the switch out of the circuit, but still needed it to press it to turn the motor on? Sorry if I'm misunderstanding.
Thanks for your help!
Nothing wrong with your understanding nor the results.
I failed to make it obvious that only the direction wiring was being altered and that the on/off sequencing was still required..
A few words regarding the switch functions.
The switch does three things.
1) turning the power on/off.
2) controlling the run direction.
3) inhibits switching direction before motor 'stops'.
The switch mechanicals(and key lock) with a center off position(which MUST be traversed) prevents(maybe) attempts to reverse direction before the motor slows down to near stop.
The direction switching ONLY affects the motor run direction during the start cycle(when the start circuit is energized). Once the start switch(or relay) opens the start circuit, the run direction circuitry has NO effect.
IF you are adventurous, the switch can (maybe) be restored to correct functioning. A persnickety task that has no guarantee of long term success. IF the sliding contacts are destroyed due to arcing, all chances of success is greatly diminished. The slidint contacts become weak(low leaf spring tension). High temps cause by high currents/arcing causes that weakening. This is surprising as the switch is a modified design of a GE range(burner) switch.
In any event the two primary functions can be duplicated with a DPST(power) switch and a DPDT(direction) switch. That leaves the interlocking up to the operator.
P.S. Depressing either the FWD or REV button should make it run(same direction controlled by the bypassing thee did).
Re: Shopsmith Mark 5.7 project
Posted: Sun Apr 12, 2020 2:55 pm
by FissionChips
JPG wrote:
Nothing wrong with your understanding nor the results.
I failed to make it obvious that only the direction wiring was being altered and that the on/off sequencing was still required..
A few words regarding the switch functions.
The switch does three things.
1) turning the power on/off.
2) controlling the run direction.
3) inhibits switching direction before motor 'stops'.
The switch mechanicals(and key lock) with a center off position(which MUST be traversed) prevents(maybe) attempts to reverse direction before the motor slows down to near stop.
The direction switching ONLY affects the motor run direction during the start cycle(when the start circuit is energized). Once the start switch(or relay) opens the start circuit, the run direction circuitry has NO effect.
IF you are adventurous, the switch can (maybe) be restored to correct functioning. A persnickety task that has no guarantee of long term success. IF the sliding contacts are destroyed due to arcing, all chances of success is greatly diminished. The slidint contacts become weak(low leaf spring tension). High temps cause by high currents/arcing causes that weakening. This is surprising as the switch is a modified design of a GE range(burner) switch.
In any event the two primary functions can be duplicated with a DPST(power) switch and a DPDT(direction) switch. That leaves the interlocking up to the operator.
P.S. Depressing either the FWD or REV button should make it run(same direction controlled by the bypassing thee did).
Thank you! I noticed the selector plate (part 501349) is missing. Could this be the crux of the whole problem? It didn't come with a key, either. Otherwise I might try to refurbish it just for fun.