Grinder Build Kicking My Butt...

Phil Dwyer

Phil Dwyer

Joined
Feb 28, 2006
Messages
3,494
Hi Friends,

Well, I'm finally getting a grinder put together and it's kicking my butt. I started collecting stuff way back when the NWG design came out. After looking at photos of so many grinders (haven't seen many in person) I decided to get in gear and give it go. I just had a four day weekend off from school with wife and kids out of town, so took the plunge. It ain't pretty, but I hope to get it to fly.

attachment.php


Looks like I might have the DC motor and controller figured out. My next hurtle is getting all the wheels to be square and coplanar. What a bugga of a task, especially if you're a hack like me. This post of Brian Fellhoelter's is helpful, but I'm still struggling. Got any suggestions?

A couple other challenges I'm having are...

  • Figuring out how to have a 1/2" bolt/shaft reduce down to the 8mm ID of the skateboard caster bearings. Is there such a thing, or would it have to be custom turned?
  • Anyone know where to get some conical shaped (or some such) 1/2" bushing washers that allow the bearing to spin freely when everything is tightened up?
  • Having trouble sourcing some 2"x3" angle iron for platens. Steel suppliers in Honolulu sell it by the full 20' length. Anyone know where I can source some? Mickley only seems to have 1.75"x1.75".
Thanks guys. Wish me luck.

Phil
 
Last edited:
i would put a rubber contact wheel on the motor instead of the aluminum one it just makes more sense for grip in my opinion seems like it would just spin under the belt without the belt moving just my 2cents
 
I'll mail the 2"x3" angle tomorrow. Its been on my to do list since just after Elk season.... :o:(.....I'll add those forge parts too. I'll tape a piece or two of Pyroceram to the angle and hope it makes it. I have plenty of packing material.
I brought home some thin plywood for a liner for the USPS box. If I'm under the weight I'll throw in a 2-1/2"x5"x9" forklift tine drop. I have another one I'm shipping to another forum member tomorrow too.

I tried conical washers with my budget wheels, I ended up pressing the bearings out and adding a spacer between the inner raceways of the bearings... I might have a few to send.
 
Last edited:
I think you are over thinking it.

Are you trying to align everything before fixing the motors position? In my recent build I got everything running (so I could reference the belt)and aligned everything to my attachments so they can be shared between two grinders. I used a washer or two to get everything aligned.

I did notice that the h/w store I sourced my washers from had two different OD washers in the same bin with the same ID; I used the smaller version and they worked perfectly.

What about using smaller angle as a bracket to mount a replaceable platen to? Most home improvement stores sell courtesy lengths of smaller angle and then in your next next steel order order some .375x2" O1 so you can make a hardened platen. Or take advantage of Brian's generous offer.

And don't worry about a rubber drive wheel.
 
A lot of steel suppliers have 'cut offs' they may sell you short pieces of angle iron.

The shaft that you need reduced down to 8mm. You can do that your self easily enough if you have access to a lathe. Then you can cut the 8mm threads by hand with the correct die. Or, you could take some 8mm all thread and shim it out to 1/2"
 
mike nelson said:
i would put a rubber contact wheel on the motor instead of the aluminum one it just makes more sense for grip in my opinion seems like it would just spin under the belt without the belt moving just my 2cents
Click to expand...
I've heard of folks doing that with good success. I'm going to give the aluminum a try since I've got it and it seems to be an industry standard. You should have seen my first effort for a drive wheel. I tried to "turn" one out of kiawe (mesquite) wood.

Brian Ayres said:
I'll mail the 2"x3" angle tomorrow. I'll add those forge parts too. I'll tape a piece or two of Pyroceram to the angle and hope it makes it. I have plenty of packing material.
Click to expand...
Thanks so much Brian! That would be a FANTASTIC help.

Brian Ayres said:
I tried conical washers with my budget wheels, I ended up pressing the bearings out and adding a spacer between the inner raceways of the bearings... I might have a few to send.
Click to expand...
I see said the blind man. You shimmed the bearings out enough so they can keep spinning freely when everything's tightened up on the shaft. Hmmm, guess it wouldn't take a very thick shim. Where did you source them?

jonekatt said:
probably a shot in the dark but are these the type of washers you were looking for http://www.grainger.com/Grainger/co...ashers?Ndr=textsearchesinbase+true&sst=subset
Click to expand...
I looked at some of those. They're pressed out of pretty thinned walled metal. Couldn't find one with 1/2" ID though. Since the protruding rim doesn't come straight up from the center not sure it would hug the shaft close enough to leave the bearing spinning free anyway.

mike nelson said:
what do you mean it aint pretty... a little bit of paint and some pin strips and it will look like it just rolled out of a factory somewhere ;0)
Click to expand...
Ha, ha...a lot of paint you mean!
 
To fix my bearing sideload issue I went hitech... I bought a couple Redhead, sleeved concrete anchors that had a 1/2" bolt. I then took the sleeves off and took them to my disc and ground them down to the exact dimension between my bearings. Using the part designed for a 1/2" bolt gave me pretty good results. this allowed both the inner and outer raceways to have close to equal load.
Have you e-mailed me you address?
At first when I tightened the nuts to eliminate slop the wheels would stop after one revolution. After adding the spacer between the bushing I got closer to ten.
 
David66 said:
I think you are over thinking it.
Click to expand...
Not sure about that one. If I had thought a little more clearly ahead of time I might not have so many alignment issues now.

David66 said:
Are you trying to align everything before fixing the motors position? In my recent build I got everything running (so I could reference the belt)and aligned everything to my attachments so they can be shared between two grinders. I used a washer or two to get everything aligned.
Click to expand...
Wow, if I was trying to make my tool arms work on multiple machines my problems would probably multiply exponentially. Yes, I'm trying to get the drive wheel on the motor lined up with the tracking wheel and the contact and/or idler wheels on the tool arm. I've decided not to worry about the drive wheel at the moment. I think concentrating on the tool arm and idler wheel alignment first is best.

Unfortunately--between my shake and bake welding alignment and drilling the shaft holes from one side of the square tubing and then the other side--some of the wheels are slightly out of square to the frame which exacerbates the challenge of getting them coplanar. Even simple things like the contact and idler wheels being 2" wide while the drive and tracking wheels are 2.25-2.5" wide slightly complicates lining things up.

David66 said:
I did notice that the h/w store I sourced my washers from had two different OD washers in the same bin with the same ID; I used the smaller version and they worked perfectly.
Click to expand...
Ya, I've got different sized OD thus different thickness washers too. It does help.

David66 said:
What about using smaller angle as a bracket to mount a replaceable platen to? Most home improvement stores sell courtesy lengths of smaller angle and then in your next next steel order order some .375x2" O1 so you can make a hardened platen. Or take advantage of Brian's generous offer.
Click to expand...
Yay for Brian!!!
 
wolffbite said:
Not sure if these bushings are what you might be looking for?
http://usaknifemaker.com/grinders-sanders-all-kinds-c-99/grinder-parts-contact-wheels-c-99-60/machinery-bushing-1-2-by-14ga-10pk.html
Click to expand...
Ya, I'm using those now. They don't just ride on the inner race (if that's the right word) of the bearing though, so when they're tighten against they squeeze the bearing into not spinning freely.

wolffbite said:
A guy who did a build in a thread a while back turned his own bushings but I would have no idea how to go about that lol...
Click to expand...
Me neither.
 
Frank Niro said:
The drive wheel does not need to be rubber coated nor does the idler wheel. Frank
Click to expand...
Thanks for the tip. I believe I'll be happy with the aluminum drive wheel. My cousin bore it out for me and re-keyed it to fit the 7/8" motor shaft. I'm trying to use a 2" rubber idler wheel so it can double as a small contact wheel too.
 
Brian Ayres said:
To fix my bearing sideload issue I went hitech... I bought a couple Redhead, sleeved concrete anchors that had a 1/2" bolt. I then took the sleeves off and took them to my disc and ground them down to the exact dimension between my bearings. Using the part designed for a 1/2" bolt gave me pretty good results. this allowed both the inner and outer raceways to have close to equal load.
Click to expand...
Sounds like my kind of fix. I'll see about rounding one up. Guess you could cut numerous shims from one sleeve. Most of the anchors like that I've seen, the sleeve has an "open" or un-welded seam. Maybe I can find one that "seamless."

Brian Ayres said:
At first when I tightened the nuts to eliminate slop the wheels would stop after one revolution. After adding the spacer between the bushing I got closer to ten.
Click to expand...
I presume you're referring to spinning the wheel by hand to see how freewheeling it is.

Brian Ayres said:
Have you e-mailed me you address?
Click to expand...
Sent ya a PM. Please let me know if you didn't get it. THANKS sooooooo much!
 
jonekatt said:
This might work for your bushing in between your bearings http://www.grainger.com/Grainger/DAYTON-Sleeve-Bearing-3FJN4?Pid=search

I don"t know what shaft size you have but there are a lot of sizes to choose from, 9/16 and 5/8 are also avalible
Click to expand...
Hmmm, I might could chuck that up in my drill press and file a rim at an angle to do the job for the 1/2" shaft bearings. Might also be able to find the size I need to sleeve the skateboard casters' 8mm (5/16") shaft to fit in the 1/2" holes in the Polar Bear platen arm.

Edit: Just realized, doubt my drill press chuck will open to hold 3/4".
 
Chris Pierce said:
A lot of steel suppliers have 'cut offs' they may sell you short pieces of angle iron.
Click to expand...
Got my fingers crossed for Brian's help, as at this point I haven't stumbled across any drops.

Chris Pierce said:
The shaft that you need reduced down to 8mm. You can do that your self easily enough if you have access to a lathe. Then you can cut the 8mm threads by hand with the correct die. Or, you could take some 8mm all thread and shim it out to 1/2"
Click to expand...
Yup, one or the other. I guess shimming it out with sleeve bearings might be easiest, especially since I don't have a lathe or metric dies.
 
Phil, you could call some skate shops to see if there any around that sell bearing spacers. Of course, they will be the right size already. Or, in the Hillman drawers at your local hardware store (I recommend Hardware Hawaii, but I used to work there) look at the steel spacers and bronze spacers/bushings to see If you can find a sleeve the right I.D., then you can cut and square it to the proper length with your bandsaw and grinder.

Another thing: if you get some 8mm hex nuts from the hardware store, you might be able to grind the corners off until they will press fit cold into the 1/2" holes in the GIB platen. If you picture it for a minute you'll see how they could be drawn in with an 8mm bolt, a larger nut and a washer. Then you could even braze or weld them in there if you wanted to. Either way, a fender washer on each side will keep them square in use.

As for steel, looks like you may have a line on some already, but remember that hardware stores may have some overpriced mild steel in a pinch, and that job machine shops will often cut and sell pieces of their stock. Don't know if there are any scrap yards in Honolulu area, Sand Island maybe, but that may be an option.

Another thing, if you are trying to set the motor correctly aligned with the grinder, you can use welding clamps to try-set it, then set the tracking neutral and install a belt. Spin by hand or even power the motor when you think it's close, shift the motor if necessary for correct tracking, when you find where the motor has to sit for the tracking to be correct with the idler in a neutral position and the belt riding centered on the wheels, mark and punch for the mounting bolts. You could get an idea of where to start with motor position by using a long straight edge from the face of the drive wheel to the grinder frame. Not that they should be flush, but more importantly that they are parallel.

Good luck!
 
Last edited:
You must log in or register to reply here.
Back
Top