Shopsmith Forums

Thanks for the reply. I wasn't planning on disconnecting the ground. I'm not replacing the wire from the switch to the motor or the ground wire from the motor to the power cord, they all look good. Only was only going to replace the hot and common from the new power cord at the switch and reconnecting the ground from the power cord to the one already connected to ground.

algale wrote:Ed,
Would you mind expanding on this thought? What gauge wire does Shopsmith use in its "stock" cord and what differences did you note by moving to #12 wire?

Thanks,

Al

The original SS cord is #14 wire. I used mine usually with a #12 extension cord and never had a problem. Never blew a breaker, never noticed much more than a slight dimming of the lights.

I exchanged the SS cord for a new cord #12 cord that is about 20 feet long. Again no problems, no tripped breakers and no real dimming of the lights.


However and this could be my imagination I have noticed a marked improvement of power. I once ripped so 2x4 on edge cutting about 3 inch depth. So the blade was buried. The SS did it but it was work. I had to turn do the speed control and be very patient. I have retired this with my new cord and the results pleased me. Same cut same board same blade only this time the the speed was up to normal saw speed range and my feed rate was what I would consider normal.

While I have no real empirical scientific data to prove or disprove any of this, I can only think of what may have been a problem.

Old cord had a bad connection at the switch. There was no visible signs of this.

Old cord was defective. Again no signs of this.

The 20 feet of #12 extension cord had an effect on this. Nothing I can see.
However in the second cut the extension cord was not used (no longer needed) Cord is used today with other tools with no adverse effect.

Plug going into the extension cord was bad. No visible signs of this.

2x4 used in first test was under tension and was twisting and I didn't realize it. Again no visible signs of this.

2x4 used in the second test was lighter density thus easier to cut

Or and one I like to believe is the #14 wire used by SS while doing the job supplied less voltage to the motor than the #12 wire did and more voltage made the SS run better.

I'm personally convinced of the results and I would never never never go back to a #14 wire. In fact if I were to do it over I would probably use #10 wire.

To me the difference between the #14 and #12 on my SS are day and night.

Thanks all for your replies and suggestions. My original post was, "could you replace the power cord without taking off belts and dropping the motor pan." I think the answer is "it depends". If you are just replacing the power cord and not the wires from the switch to the motor, then yes I think you probably could. That said, I think the more practical answer is why would you. Taking the dust cover off and dropping the pan was very straightforward. You may as well do it that way and give yourself a little more room to work not to mention the opportunity to learn a little more about your machine. It also provided and opportunity to clean things up a bit inside, I doubt anybody has been in there since 1958.

Ed in Tampa wrote:The original SS cord is #14 wire. I used mine usually with a #12 extension cord and never had a problem. Never blew a breaker, never noticed much more than a slight dimming of the lights.

I exchanged the SS cord for a new cord #12 cord that is about 20 feet long. Again no problems, no tripped breakers and no real dimming of the lights.


However and this could be my imagination I have noticed a marked improvement of power. I once ripped so 2x4 on edge cutting about 3 inch depth. So the blade was buried. The SS did it but it was work. I had to turn do the speed control and be very patient. I have retired this with my new cord and the results pleased me. Same cut same board same blade only this time the the speed was up to normal saw speed range and my feed rate was what I would consider normal.

While I have no real empirical scientific data to prove or disprove any of this, I can only think of what may have been a problem.

Old cord had a bad connection at the switch. There was no visible signs of this.

Old cord was defective. Again no signs of this.

The 20 feet of #12 extension cord had an effect on this. Nothing I can see.
However in the second cut the extension cord was not used (no longer needed) Cord is used today with other tools with no adverse effect.

Plug going into the extension cord was bad. No visible signs of this.

2x4 used in first test was under tension and was twisting and I didn't realize it. Again no visible signs of this.

2x4 used in the second test was lighter density thus easier to cut

Or and one I like to believe is the #14 wire used by SS while doing the job supplied less voltage to the motor than the #12 wire did and more voltage made the SS run better.

I'm personally convinced of the results and I would never never never go back to a #14 wire. In fact if I were to do it over I would probably use #10 wire.

To me the difference between the #14 and #12 on my SS are day and night.

You make some good points, but experience tells me that the original Shopsmith design engineers wouldn't have cut a few pennies of cost if it made a significant difference in performance. So I went throught the analysis. (JPG has exercised admirable restraint here, but I just can't help but be a smart-alec.)

14 gauge wire has a resistance of 2.525 milliOhms per foot. 12 gauge wire has a resistance of 1.588 milliOhms per foot. Let's assume that your power cord was 8ft long. Then the conductors run (in both directions) for a total of 16 ft.

So then the difference in total resistance is 16x(2.525-1.588) = 15 milliOhms. Now let's assume that you are on a 20A circuit. The worst case extra voltage drop is 20A x 0.015 Ohms = 0.3 Volts. Noise level .. the power company's supply is not nearly that consistent. And don't even start thinking about inductance, etc. When it comes to power cord at 60 Hz, only the resistance matters.

The old "Post hoc, ergo propter hoc" logical fallacy strikes yet again!

Look for the real reason somewhere amongst the other possibilities that you have identified.

I continue to be 'admirable'!:D















BTW: Well said!:D

Methinks Ed's plug is the culprit! The old cord plug/extension cord socket were more 'compatible'.

I doubt Ed was hallucinating!;)

[quote="BuckeyeDennis"]You make some good points, but experience tells me that the original Shopsmith design engineers wouldn't have cut a few pennies of cost if it made a significant difference in performance. So I went throught the analysis. (JPG has exercised admirable restraint here, but I just can't help but be a smart-alec.)

14 gauge wire has a resistance of 2.525 milliOhms per foot. 12 gauge wire has a resistance of 1.588 milliOhms per foot. Let's assume that your power cord was 8ft long. Then the conductors run (in both directions) for a total of 16 ft.

So then the difference in total resistance is 16x(2.525-1.588) = 15 milliOhms. Now let's assume that you are on a 20A circuit. The worst case extra voltage drop is 20A x 0.015 Ohms = 0.3 Volts. Noise level .. the power company's supply is not nearly that consistent. And don't even start thinking about inductance, etc. When it comes to power cord at 60 Hz, only the resistance matters.

The old "Post hoc, ergo propter hoc" logical fallacy strikes yet again! ]

If a cord of only 8ft is used then I agree. However I think most find the standard cord on the SS is too short (at least I did) so they use an extension cord. Now many factors come into play. Resistance at the connection, the length of the extension and quality of the extension.

What I did by lengthening my cord using high quality wire was eliminated many feet of extension cord that I didn't want or need, an extra connection, and questionable quality.

As I have said I do not have empirical data to prove or disprove my claim. But for me the "perceived" performance increase put a smile on my face and keeps it there every time I run my Shopsmith.

And believe me I am exhibiting a lot of restraint myself.

Ed in Tampa wrote:If a cord of only 8ft is used then I agree. However I think most find the standard cord on the SS is too short (at least I did) so they use an extension cord. Now many factors come into play. Resistance at the connection, the length of the extension and quality of the extension.

What I did by lengthening my cord using high quality wire was eliminated many feet of extension cord that I didn't want or need, an extra connection, and questionable quality.

As I have said I do not have empirical data to prove or disprove my claim. But for me the "perceived" performance increase put a smile on my face and keeps it there every time I run my Shopsmith.

And believe me I am exhibiting a lot of restraint myself.

Yep, I find the standard cord too short myself -- I have to re-route it every time I raise up to drill-press mode. And I agree that any extension cords should be heavier than 14 gauge -- I use a 10-gauge extension cord for power tools when I'm working outdoors. My only point was that 14 gauge should be adequate for the factory power cord.

Your longer heavier cord is more robust than using extension cords, for all the reasons you mention. My best guess is that you eliminated a high-resistance connection or two somewhere along the way, and that gave you the performance improvement.

I think we can all agree 'bigger' is 'better'(.);)

FWIW. I use a short #14 power card and feed it with bigger source wiring. I usually use an 8' extension cord with about 18" of the 'socket' end cut off and reterminated to attach to the switch terminals and the motor shell. That reduces the need to resize the strain relief hole.





I also prefer running my M5 on 230v(a choice made a half century ago when I purchased it new(special order!)).

algale wrote:Ed,
Would you mind expanding on this thought? What gauge wire does Shopsmith use in its "stock" cord and what differences did you note by moving to #12 wire?

Thanks,

Al

Al, I know this is apples and oranges, but here is my experience.

A few decades ago, I had a Datsun 240-Z. SWEET car!

Sometimes, especially on cold mornings, it had "issues" starting. Somewhere I had managed to find some 00 welding wire, and replaced the high power leads from the battery, to the starter and block. (ground)

After that, my cranking speed DOUBLED.

What I'm driving at, a larger diameter wire will almost always work better in power situations.

Oh, I had enough of that wire to make a set of jumper cables, longer than my Dodge Maxi-van. Best jumper cables I've ever used. You didn't need to get nose to nose, to jump someone. With the van, I could pull past them, and still give someone a jump. Handy on the freeway!

steve

I just encountered this thread for the first time and really am curious if 14 gauge wire was not what was designed with the 3/4HP motor back in the 1950's and was never revisited thoroughly when they went to 1 1/4HP motors.

Changes in start capacitors and circuits on the 1 1/8HP motors could have masked a good bit of symptoms with better starting and what you folks have discussed makes a great deal of sense as it shows up as IR Drop under loading. 12 gauge wire changes the curve fundamentally and your observations support that notion.

There is more torque through the power curve. The motor is capable, but the 14 gauge wiring introduces loading of its own that simply isn't present with 12.

Many have commented that their units run on the warm side. For those of you who have gone with 12 gauge wiring, have you noticed it reduced the heat build-ups?

Thoughts?

Everett