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Sears Craftsman Bench Grinder - any worth?

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RoninB4

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Think I’m going to pick these up tomorrow - should do the trick for the rubber feet?
-Maybe but not a guarantee. The perceived vibration is a relative description, there's going to be some with a bench grinder that's not mounted. The mass of the grinder has a lot to do with absorbing vibration, yours doesn't look like it has much mass. Have you put an indicator on the shafts to determine if they run true? IF the bearings are good then how well the wheels are balanced has a lot to do with the vibration. Many types of grinders (surface grinders, pedestal type tool grinders, tool/cutter grinders, etc,) have very little perceived vibration. Bench grinders all have some vibration present because of the lack of mass. If your grinder is bouncing on the bench then that's excessive. The less mass the greater the need to use anti-vibration measures.

-For rough grinding more vibration is acceptable, for fine grinding (cutting edges) then it becomes more important. Vibration and improved surface finish can be accomplished. How important is this to you for what you're doing? Try the rubber feet and report back.
 

larry4406

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The original rubber feet look like this
1787306002445.png

Lowes has ones that are near identical. I can't find the part number at the moment.

This style is what you want for a craftsman block grinder.
The clone rubber grommets at Lowe’s are made by Hillman. Pictures of package and grommet from my stash.

These are in the hardware section in the various drawer bins.

Exact as far as I can tell. Learned about it on this site.


IMG_1691.jpegIMG_1692.jpeg
 
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freebo86

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Well I picked up the $2.99$ stuff and cut the head as a slot and surprisingly they fit well, lol.

Here is a video of the machine running. The wheels look out of round, I do see a wobble. I did the ring test on the wheels and they’re good.

Thoughts? Is this excessive?
Garage floor test

Bench test


IMG_1676.jpeg
 

1982fxr

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The right side looks to have an issue.

But, overall, the machine is not walking, which is good. I'd check for runout on the shaft.

You could also swap sides and see if the problem follows it.
 

RoninB4

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Thoughts?
-It does "walk" when it's slowing down, that does suggest an problem that could be attended to.

-Did you put an indicator on both shafts to check for runout (power off and unplugged).
Is this excessive?
-For some it's tasks it's ok, for grinding woodworking tools with a sharp edge.....no. You can attempt to balance the wheels (off the grinder spindle), then dress them accordingly. There are also better elastomers and mounting the grinder that should help but it's really about what the task is and how much effort returns the result you want/need. It doesn't look horrible but it could probably be better. This is a bench grinder and, like everything else, there's a point of diminishing returns that only you can decide. Test and post results.
 
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freebo86

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Check salt a
The right side looks to have an issue.

But, overall, the machine is not walking, which is good. I'd check for runout on the shaft.

You could also swap sides and see if the problem follows it.

so I’ve learned that I shouldn’t put the shaft nut on with a impact 🤦‍♂️ so I may have warped it I guess..

I’ll see what I can do, like I said I may swap one of the wheels for a 7” wire wheel it would serve me more than 2 grinding stone wheels. Was going to grab this -

 

RoninB4

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so I’ve learned that I shouldn’t put the shaft nut on with a impact 🤦‍♂️ so I may have warped it I guess..
-No you should NOT use an impact for the spindle nuts. :bitchslap That's a good way to overstress the grinding wheels and cause a fracture in the wheel that explodes at startup. One side should be a left-hand thread, the other side should be a right-hand thread. This is done so that wheel rotation direction prevents the nuts from getting loose. A moderate amount of finger pressure on a wrench/socket applies sufficient pressure to keep the nuts adequately tight. With precision surface grinders the only wrench ever used is about 6"-7" long, a surface grinder will spin up more RPM than a bench grinder and that short wrench is what almost everybody uses. If I had to take a WAG then about 22-25 ft./lbs of torque is average. You want to use the paper blotters I've posted about before to avoid metal to grinding wheel contact.

-If you've warped the metal disc from over-tightening then do replace it.
 

Cruzan80

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If you used an impact, I would not trust the wheels AT ALL! Too high of a chance of introducing small fractures that can shatter it later.

I have seen people run the nut down with an impact if they were using one side without a wheel, just to check balance on the other. That is the only (possible) reason for an impact here, IMO. I dont like to even use one for loosening (not worth the risk to me).
 
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freebo86

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-No you should NOT use an impact for the spindle nuts. :bitchslap That's a good way to overstress the grinding wheels and cause a fracture in the wheel that explodes at startup. One side should be a left-hand thread, the other side should be a right-hand thread. This is done so that wheel rotation direction prevents the nuts from getting loose. A moderate amount of finger pressure on a wrench/socket applies sufficient pressure to keep the nuts adequately tight. With precision surface grinders the only wrench ever used is about 6"-7" long, a surface grinder will spin up more RPM than a bench grinder and that short wrench is what almost everybody uses. If I had to take a WAG then about 22-25 ft./lbs of torque is average. You want to use the paper blotters I've posted about before to avoid metal to grinding wheel contact.

-If you've warped the metal disc from over-tightening then do replace it.

If you used an impact, I would not trust the wheels AT ALL! Too high of a chance of introducing small fractures that can shatter it later.

I have seen people run the nut down with an impact if they were using one side without a wheel, just to check balance on the other. That is the only (possible) reason for an impact here, IMO. I dont like to even use one for loosening (not worth the risk to me).

Throw those wheels in the garbage. The impact trashed them, period.


😭😭😭😭

If I am replacing the wheels at this point, is there any point in downsizing to 6” vs 7” wheels? This thing would be for general garage use. My setup would be a wide wheel and 36 grit wheel.
 
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freebo86

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-Better quality grinding wheels (for surface grinders anyway) have the plastic bushings. These help avoid metal-to-wheel contact that can lead to stress fractures in the wheel. Even a paper/carboard bushing is more desirable that those without.

-Yes those should be there. To avoid the metal-to-wheel contact a circular piece of thicker paper (called a "blotter") is used on either side of the wheel. It's no absolutely critical but it is something you want to have. If blotters aren't available they can be easily made from construction paper.

Are these the blotters you speak of? I’m having a time trying to figure out what this blotter / construction paper stuff is and does?

IMG_1680.jpeg
 

Cruzan80

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Yes, those are the blotters. They are there so the flange doesnt make direct contact and it prevents high-pressure spots by squishing and evening out the force.

Re. 6 vs 7" wheels, no real issue besides adjusting the tool-rests. IIRC, there are more options in 6" than 7".
 

RoninB4

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What @Cruzan80 said. As for the wire wheels....you ought to obtain "gauntlet" type of gloves to protect your hands/wrists when the wires come out of the wheels unless you like acupuncture. Can't recommend a brand, they all seem to give up the wires at some point during heavy use. Every place the wires puncture your skin has a good chance of becoming infected, metal carries nasty things with it that set up bacterial colonization. That doesn't always mean you need a tetanus shot. I've never had to get one but that may be I'm somewhat immune from the hundreds of metal lacerations I've had. It's still painful picking dirty metal wires out of your skin and the ensuing infection sites can be avoided with a good pair of heavy gauntlet gloves.

-Just like with grinding wheels you should select the wire wheel according to the type of work you intend to do. Brass wire wheels are more expensive and wear faster but they don't damage the surface, that's important to me sometimes. The diameter and count of the wires is up to you too. Thicker wire with less of them makes the wheel a "coarse" type that's faster at removing crud but has more of a tendency to "grab" the workpiece and pull your hands and the workpiece into the wheel. Smaller diameter wire with more of them makes a "fine" wheel that's less aggressive, more flexible, and leaves a nicer brushed finish but may not be stiff enough to remove heavy rust on the workpiece.

Sounds like there's a lot decisions to make with metalworking equipment? There always is for every process. A lot to learn? Yes and no, depending upon the process. It's not a simple matter of get the machine and power it up. More learning yields better/safer results. OBTW, don't use an impact gun on any type of machine or tooling again, for risk of cross threading. Impact guns may be faster but also means it can eff-up what you're doing faster. I bought my first electric impact two months ago just for changing the anode in my water heater. Impact guns may be a staple for mechanics but there's a whole lot of people that don't know how to use them properly and eff-up the project. It's a pet peeve of mine. Rant over.
 

Lassen Forge

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Only issue with bronzze/brass wire wheels is they WILL transfer some of the yelloe metal onto whatever you're wire brushing.

-I can see where your field data might have led to your conclusion. You'd also have to include the sheer number of idiots out there in with access to those wheels. I've run into them in machine shops where they ought to know better (but didn't seem to).

We had a real Doctoral candidate of an employee who, instead of getting the right handle for the highway pushbroom (of which we had metric f***loads) with a taper that wedged to the broom head, he took a different one (the screw in type like we used for the soft warehouse brooms) and proceeded to cut off the threads, then sat for nearly an hour filling the shop up with smoke while he attacked this wooden handle with the bench grinder... then comes to me and asks why it's not working.

I asked him if he was making an ugly stick that I could beat him with.
 

RoninB4

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Only issue with bronzze/brass wire wheels is they WILL transfer some of the yelloe metal onto whatever you're wire brushing.
-Yep, brass is softer than steel (for others reading this) so it can/will impart/imprint brass onto steel. For more delicate threads I don't like risking what steel wire will do to precision surfaces. Most times the rough onslaught of steel-on-steel is good enough.
We had a real Doctoral candidate of an employee who, instead of getting the right handle for the highway pushbroom (of which we had metric f***loads) with a taper that wedged to the broom head, he took a different one (the screw in type like we used for the soft warehouse brooms) and proceeded to cut off the threads, then sat for nearly an hour filling the shop up with smoke while he attacked this wooden handle with the bench grinder...
-...and likely clogged the grinding wheel with resin/pitch/wood fibers too. How's that old ad go.....1787491858565.png
then comes to me and asks why it's not working.
-"Maybe you should have asked me IF it would work beforehand but I don't want to deny you the self-discovery that you effed up"
I asked him if he was making an ugly stick that I could beat him with.
-"Oops, I can see someone else already used one on you."
 
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