Speed Control and Frightening Noises

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dusty
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Speed Control and Frightening Noises

Post by dusty »

I had something happen today that has not happened since I got my SS in the late 80s.

I had been cleaning and lubricating my 510. It was all closed up and ready to back into service. I turned it on and ran it through a speed change from low to high speed. I was very near the top speed when suddenly I heard what I would describe as metal to metal scrapping. Really sounded BAD. I backed off the speed the noise became normal. I once again approached the top end (very carefully, I might add) only to hear the noise again.

I backed off the speed, shut it down and opened for an inspection of damage. I see none. With it open, I ran it back up to near top speed to see if I could locate the source of the noise. I did not and as long as I stay below "S" (on the speed dial) I hear nothing unusual.

I don't have a problem until I get up into the top of the 'Shaping/Routing' speeds.

It's Christmas time and I have a build schedule to keep so I closed without further delay and went back to work,

Does anyone have any suggestions as to what might be causing the noise.
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reible
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Post by reible »

Sounds to me like a case of the control sheave assembly hitting the speed control bracket... resetting the high speed stop should fix it. Look for the section called adjusting the high speed setting in your manual.

Ed
alberrt2
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Post by alberrt2 »

I agree it sounds like the control sheave assembly. I just had the same problem with the loud screaching. My assembly eventually went bad and I replaced it. Seems there are bearings in the end of it; perhaps you know that, but I didn't. My lubricating must not have been enough and the bearings must have gone dry. Anyway it works fine now.
rolands
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Post by rolands »

I just replaced my Control Sheave assembly last week and I'm sure it failed after 18 years because of lack of proper maintenance, but I'm not sure that I have the speed adjusted right. Even tho the saw works well, the speed doesn't sound just right. SS sent instructions on high speed adjustment with or without a tachometer and I did it without a tachometer. I can get a automotive tachometer, but can this be used on the SS to adjust the speed? If so, how is it connected? I would really like to make sure that the high speed is at 5200 rpm. If anyone can help me with my lack of knowledge here, it would be appreciated. Thanks.
8iowa
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Post by 8iowa »

My headstock (1983 model) has just developed a rattle and scraping noise. As I moved the speed dial up it got worse. I installed the new 2 bearing quill but that did not change anything.

In 2000 I replaced the control sheve assembly because the bearing failed. It actually disintegrated. This is a permanently sealed bearing which cannot be re-greased. The headstock had worked fine - until now.

Since my son and I have used this machine a lot through the years I decided to return it to Shopsmith's repair service in Dayton. After all those years of faithful service I decided that the headstock deserved to be re-furbished.

The hardest part of the job was in building a "double cardboard" box. I glued styrofoam blocks to the bottom and stuffed heavy craft paper quilted pads all around the headstock. It costs $41.27 to ship the unit to Dayton via UPS, which includes $7.50 insurance.

In 2-3 weeks they will inspect the headstock and then call me to authorized the necessary repairs. I'll report back here as to their findings and repair costs.
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dusty
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Speed Control and Frightening Noise

Post by dusty »

Does the scheduled headstock refurbish result in a 1 1/8 hp motor or does SS simply recondition the motor in its original configuration?

If you get the larger motor it'll probably seem like it has been turbo charged.

Just curious.

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8iowa
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Post by 8iowa »

Dusty:

Dave in Shopsmith's Dayton retail store told me that they do not service the motor. They will install a new motor if you wish. The cost is $350. It's also a fact that most single phase motors made since the 60's are not very serviceable anyway. ( I used to work for Delco in Dayton back when they made electric motors)

If you have the older Mark V with a 3/4 HP motor, the 1 1/8 HP motor replacement would be a natural if you are going to go to the effort to send your headstock back to Shopsmith to be re-conditioned. Your old motor may have seen it's best days anyway.
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billmayo
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Shopsmith Motors

Post by billmayo »

I feel the 1 1/8 HP motors (1960 and later) are very serviceable. If there is a burnt smell from the motor, then replace it, don't have it rewinded. I had no problem finding several local electric motor rebuilders who would replace the bearings and clean up the start winding contact points for around $70-$75. Since I had the first motor rebuilt (time constrant), I have been replacing the bearings and cleaning the points myself for any headstock I sell or repair. I find the front bearing (next to the fan sheave) will need replacing most of the time, so I just replace both bearings since the motor is disassemblied. Also, I find that most floating sheaves (on the motor shaft) will have a slight sticking problem. I always removed it to clean the inside of it and the motor shaft of any old oil/sawdust/etc (crud). I have a pdf Shopsmith instruction on how to remove/replace motor spring if anyone needs it.

Bill Mayo billstoolz.com
8iowa wrote:Dusty:

Dave in Shopsmith's Dayton retail store told me that they do not service the motor. They will install a new motor if you wish. The cost is $350. It's also a fact that most single phase motors made since the 60's are not very serviceable anyway. ( I used to work for Delco in Dayton back when they made electric motors)

If you have the older Mark V with a 3/4 HP motor, the 1 1/8 HP motor replacement would be a natural if you are going to go to the effort to send your headstock back to Shopsmith to be re-conditioned. Your old motor may have seen it's best days anyway.
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Nick
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Post by Nick »

Dusty, sorry it took me so long to wade into this thread but I needed to gather some information from my factory snitches to be better able to answer you and they were unusually hard to contact. You'd think it was Christmas or something.

I gather from the thread that you've progressed from fixing the metalic sound yourself to having the headstock rebuilt. If the sound at high speed is really all that's wrong, you may want to think again. It's an easy fix.

The sound you're hearing is the control sheave rubbing on the speed control mechanism (indicated by the arrows in the photo below). As you dial in a higher and higher speed, the control arm pulls the control sheave away from the idler sheave. Ordinarily, a long, threaded allen screw stops the control arm when the speed is as high as it will go and prevents the arm moving the control sheave so far that it rubs. Occassionally, this allen screw loosens and the screeching begins.

[ATTACH]36[/ATTACH]

Remove the rear cover from your headstock and (carefully now, the protective cover is off) run the speed up to where the top surface of the V-belt is just below the rim of the drive sheaves, as shown in the following photo. If you have a new belt and its width is still close to 1/2", it should be 1/16" below the rims. If you have an older belt and the width is 15/32" or less, make it 1/8" below the rims. (If your belt is less than 7/16" wide, get a new one.) This is where your belt should end up when the speed indicator is on "FAST." By the way, Roland, this is also where the belt ends up when the machine is running at 5200 RPM with a broke-in belt. When the belt is brand new, the Shopsmith will only run at 4800 RPM. Try to adjust it higher and you'll get the screech that is ruining Dusty's holidays. As the belt breaks in, it stretches and narrows slightly -- and the speed of the machine goes up to 5200 RPM.

[ATTACH]37[/ATTACH]

Remove the Speed Dial with a 3/32" allen wrench and loosen the jam nut on the idler gear. You may find it is already loose -- this is what holds the allen-screw-speed-control-stop in place. Turn the allen screw with a 1/8" allen wrench until you feel it push against the control arm. (See photo below.) Hold the set screw with the wrench so it doesn't turn and tighten the jam nut.

[ATTACH]39[/ATTACH]

Reset the outer ring gear of the speed control mechanism so that the pointer on the headstock lines up with "FAST" on the ring gear. Replace the the speed dial. (See photo below.) Turn on the motor and run the speed control through the range of speeds several times. The screech should be gone and the dial should stop at "FAST."

[ATTACH]40[/ATTACH]

Oh, yeah. While you've got the rear cover off the headstock, suck out the fine sawdust and oil that puppy.

With all good wishes,
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Nick
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Post by Nick »

Albert, while my camera is still warm I thought I'd comment on your experience with the itty-bitty bearing in the control sheave. There is indeed one there folks, and it's not sealed. (See photo below.) Needs some attention and few kind words now and again. The lubrication you put in the hole in the control sheave shaft finds its way to the bearing and makes it feel appreciated. That's why we changed the maintenance instructions a ways back and upped the recommended dosage of oil from 2-3 drops to 5-6. Got a lot of warm, fuzzy thank-you notes from happy bearings for that.

[ATTACH]41[/ATTACH]

By the way, don't try to oil this bearing from the outside. The oil you leave on the surface will attract fine sawdust and wick the lubrication right out of the bearing.

Want to see what happens when you ignore this little bearing? The photo below is from the "Hall of Shame" where our rebuilders keep a few of the old parts that were subjected to extreme abuse. You're looking at a ruined control sheave in which the bearing froze and the coupler that hooks the control sheave to the control arm twisted off. The owner, whose head and headstock were both full of sawdust, kept on working! You think that the screeching that Dusty reported was annoying? Grown men weep at sounds such as this must have caused. In short order, the friction heated the control arm and it actually welded itself to the control sheave. The control arm broke off and the owner finally decided to quit.

[ATTACH]42[/ATTACH]

The moral of the story is that 5-6 drops of oil in the right place at the right time will go a long way to insure that you and your machine continue to work happily ever after.

With all good wishes,
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