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Problem with grinder build!


Pelallito1
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Help! :wacko: I've hit a snag.

 

First let me say Mike Clerc's grinder plans are great. Thanks Mike.

 

Either there is a discrepency or I'm not reading the plans correctly, (the later is more likely). The snag has to do with the "tracking pivot mounts" and how they attach to the "grinder tension & tracking support arm".

 

I'll try not to confuse myself here. On the "grinder tension & tracking support arm", the plan calls for mounting holes for the "tracking pivot mounts" at 0.50" and 1.25" from the bottom. On the "tracting pivot mounts", the plan calls for holes at 0.50" and 1.75" from the bottom. The snag being the difference between 1.75" and 1.25".

 

So what is it? Am I reading the plans wrong? Is this a typo or what. It's an easy fix, I'll just measure to fit and re-drill.

But if I'm missing something, (very likely), then I sure could use some help.

 

Also, the plans call for the "tracking pivot mounts" to have a hole drilled and tapped 1/4-20 for what I am going to call the axle for the "tracking/idler roller mount" that fits in between the "tracking pivot mounts". If both "tracking pivot mounts" are drilled and tapped 1/4-20 then the bolt won't fit through to the other side. I would think one should be drilled and tapped and the other should be drilled 1/4". Help, again! :blink:

 

Lastly, the plans for the "grinder main arm-support side" show a hole to be drilled and tapped 5/16-18. I assume this is for the "die cast zinc adjustable handle w/ball knob". Mike's material list shows a handle 3/8-16 thread. If this is a typo it's also an easy fix. I'll just pick the one I like and make the hole fit it. The question is, am I reading this right?

 

This would all be so much easier if I knew what the he77 I was doing.

 

Thanks, -Art

"My sword and my shield are at your command"

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Art,

 

I'll do my best to answer your questions. I had the same ones and had to fuddle through by myself so I'll gladly share what I know.

 

On the "grinder tension & tracking support arm", the plan calls for mounting holes for the "tracking pivot mounts" at 0.50" and 1.25" from the bottom. On the "tracting pivot mounts", the plan calls for holes at 0.50" and 1.75" from the bottom. The snag being the difference between 1.75" and 1.25".

 

Art, you are right, the dimensions on the two sheets don't match. I used the dimensions shown on the Tension Arm sheet. Either way you want to do it is fine...just use the same dimensions for those holes on both parts or you will get REALLY, REALLY frustrated when it comes time to bolt the pivot mount plates on the tension arm.

 

Also, the plans call for the "tracking pivot mounts" to have a hole drilled and tapped 1/4-20 for what I am going to call the axle for the "tracking/idler roller mount" that fits in between the "tracking pivot mounts". If both "tracking pivot mounts" are drilled and tapped 1/4-20 then the bolt won't fit through to the other side. I would think one should be drilled and tapped and the other should be drilled 1/4". Help, again!

 

Yup! You're right! Pick one side to drill .250 so a bolt can slide through and tap the other one 1/4-20. I used a socket head screw for my pivot axle and it worked fine.

 

This brings up another point...there is no plan for the pivot plate, at least on my plan set. The plate is simply a piece of steel .75 x 1.5 x 2.0 with a .25 hole drilled through for the axle. Put a 1/2-13 hole smack in the center to accept the axle of your tension/tracking wheel and you are in bidness.

 

Lastly, the plans for the "grinder main arm-support side" show a hole to be drilled and tapped 5/16-18. I assume this is for the "die cast zinc adjustable handle w/ball knob". Mike's material list shows a handle 3/8-16 thread. If this is a typo it's also an easy fix. I'll just pick the one I like and make the hole fit it. The question is, am I reading this right?

 

Do what you want here, Art, because there isn't a right or wrong way. What I did was make a 1/2-13 hole about three inches back from the front of the tool arm receiver box then cobbled up a locking bolt out of some 1/2 all thread rod, a little piece of brass to keep the bolt from marring the tool arm, and some 0-1 drill rod.

 

The beauty of this grinder is that if there is something you want to change in the plans just go ahead and do it as long as it will work. Fer instance, instead of using 1/4" socket heads to attach the tension arm upright I used 3/8" grade 8 bolts for added strength.

 

I'll post a few pictures of what I've explained in hopes that it will make what I've explained here a little clearer.

 

Hope this answers your questions. If not, ask some more and I'll try to clarify.

 

K

10.jpg

16.jpg

27.jpg

3.jpg

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Art,

 

One other thing I forgot to mention about the tension arm and the tracking pivot plate...On final assembly I secured the pivot plate axle bolt and the bolt holding the tension arm to the upright with nylon locking bolts for a little added security.

 

K

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The pictures are indeed worth several thousand words.

I just finished my grinder today and would post pics but something is wrong with my photobucket account, and my feet hurt.

Tomorrow I'll clean up the bench and put away all the tools I have scattered all over the benck so it will look like I keep a clean workspace and then take some pics. Mine is a hybrid of the grinder in the pics above, KMG clone and some mutt items from other grinders. I think it will work out well tho. I used a variable speed controller and the step pulleys so I have a lot of speed/Torq flexibility. Next item is the platten,

Got some knife steel on the way too, WooHoo!

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Sixfooter, you've illustrated my point about changing plans to suit yourself. There is a wide variety of grinder designs and all will work to do the essential task of abrading materials. The only critical elements are that all the wheels are in the same plane so the belt tracks straight and there is enough tension on the belt to keep it where you want it. And, hopefully, all the parts are screwed on tight enough to keep from coming loose and bouncing off your head. Everything else is gravy.

 

K

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Thanks Ken and Sixfooter,

 

The fog is starting to lift. :)

 

I couldn't do this without you. You're lucky you don't live closer.

 

-The beauty of this grinder is that if there is something you want to change in the plans just go ahead and do it as long as it will work. Fer instance, instead of using 1/4" socket heads to attach the tension arm upright I used 3/8" grade 8 bolts for added strength.

 

I'm trying to figure out how to make my drill-press drill square holes. -Art

Edited by Art Lawrence

"My sword and my shield are at your command"

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I used all SS hardware on mine all in Allen socket screws mostly just because I could. Not quite done yet, some cleanup and paint to do yet

The basic grinder is the same as you have there but all in steel. I used a different tracking mechanism that is adjustable in 2 planes and I also used a Pinch Bolt on the end of the tool arm to facilitate tool changes, one quarter turn on the bolt and the contact wheel comes off. The idea being that I'll have (eventually) more tham one contact wheel, a platten with 2 different wheels, a small wheel tool, disk etc... all that will be very quick changeup.

All I have now is an 8" wheel, but that woll get me started.

What color should I paint this thing? After this much work rust red just isn't going to do it.

 

What do you need a square hole for?

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What do you need a square hole for?

 

"Fer instance, instead of using 1/4" socket heads to attach the tension arm upright I used 3/8" grade 8 bolts for added strength."

 

Ken milled a hole to accept the grade 8 bolt head. I was just being a wise-aker. I don't really need one. However, I am interested in your pinch bolt set-up on the tool arm. Doesn't Bader use that system? Will it work with the KMG contact wheels and spindles? Thanks, -Art

 

p.s. I snapped another 1/4-20 four flute tap. I had just started it and whammo! It shouldn't have snapped. I think the Ace taps are crummy. I ordered a 3 flute from McMaster-Carr. Twice as much, we'll see how it works. I also ordered a tap extractor. We'll see how that works too. -Art

Edited by Art Lawrence

"My sword and my shield are at your command"

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Ahh, ok now I understand the square hole thing. I used 1/4 x 20countersunk screws for the upwright and ground the heads flush.

I don't know what Bader uses, never looked at their unit that close, I saw it on that russian guys video and adapted it for mine. I ordered my contactwheel from Sunray, but its just a 1/2" shaft. I made the axle for it from 1/2" round stock cut to length and threaded it myself. I got the drive wheel and idler pulley from Beaumont and made the axle for the pivot from all thread.

I'll post a couple pics tomorrow

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Drill the big hole, then the small one and then cut the slot. The slot would make the drill bit jump around to much

 

Thanks SIXFOOTER ,

 

I should have asked before, but, how far from the end are the big and small holes? What size is your pinch bolt? By the way, I saw the Russian guy's video. He reminds me of a movie actor. Can't quite place him.

 

Thanks, -Art

"My sword and my shield are at your command"

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Art,

I cut mine all the way, so that I could slip it on and off by just loosening the Allen bolts that hold it in place. I have not noticed any lack of rigidity, by doing it that way.

Regards,

Fred

 

On the tool rest arm, are you guys cutting the bolt slot all the way out or leaving the end solid for rigidity? -Art
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Thanks SIXFOOTER ,

 

I should have asked before, but, how far from the end are the big and small holes? What size is your pinch bolt? By the way, I saw the Russian guy's video. He reminds me of a movie actor. Can't quite place him.

 

Thanks, -Art

The pinch bolt is a 3/8" grade 8 and ic on the centerline 1/2" from the end of the bar. The large hole for the contact wheel shaft is 1/2" on the other centerline 1 inch from the end.

 

For the tool rest cutting wasn't looking like a lot of fun, so I used 2 pieces of 1/4" x 1/2" bar stock and welded a small piece of steel on the ends, then cleaned the inside slot up with a few passes of the file. It is attached to the bottom of the tool arm with 2 3/8" bolts and slides in and out well. The tool rest itself it bolted onto the slide with 4 bolts from the bottom and ground off flat on top.

 

Can't say I am thrilled with the tool rest so I'll probably redesign it for something better. Eventually with some arrangement for jiggs for holding blades on precice repeatable positions.

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Thanks Sixfooter,

 

That's very helpful. Please let us know if you come up with something better for the tool rest.

 

I"m assuming that the hole for the pinch bolt is tapped on the bottom side of the slot but not above it. -Art

Edited by Art Lawrence

"My sword and my shield are at your command"

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  • 3 weeks later...

I have fallen "in like" with a spiral 2 fluted bottom tap from McMaster-Carr. They cost $10.00, (twice as much as a four flute from Ace), an cut like butta.

 

It's coming along well now. I had to find workarounds for all my foul-ups. No matter how many times I measure before I drill and tap, I feel like the guy in the Johnny Cash song who is getting his car one piece at a time from the factory where he works, and when he tries to put it all toghether all the holes are gone! -Art

"My sword and my shield are at your command"

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Art,

 

The holes aren't gone...you just have to scoop the insides out and there they are, right where they belong!

 

If you have a Fastenal store in your area you can get the 2-flute taps for about $5 each. They aren't bottoming taps but used judiciously they will do a fine job. I used them on my machine with no problems. Didn't break a single one, but by the time I finished tapping all the deep holes my nerves were shot!

 

K

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Art,

 

The holes aren't gone...you just have to scoop the insides out and there they are, right where they belong!

 

If you have a Fastenal store in your area you can get the 2-flute taps for about $5 each. They aren't bottoming taps but used judiciously they will do a fine job. I used them on my machine with no problems. Didn't break a single one, but by the time I finished tapping all the deep holes my nerves were shot!

 

K

 

I'm with you on the nerves part.

 

My next delima is the holes in the bearing mounts to attach the bearings. The plans call for holes to be drilled and tapped for a 1/4-20. I believe it was you who said they went a bit bigger and still had wobble. Is wobble part of the plan so there is some wiggle-room for adjustment? Should I go bigger yet? What do you think? -Art

"My sword and my shield are at your command"

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I went 3/8" on mine because I wear suspenders with my belt. Also wanted the larger bolts to take up a little more room in those big holes in the bearing blocks. You need a little wiggle room so you can properly align the driveshaft. I'm sure you could get by with the 1/4" bolts from a strength standpoint but you will have to put a washer under the head to keep it from falling through the hole. The 3/8" socket head screws I used didn't require the washer. Just looked nicer and added a little bit of strength. No hard and fast on this one so do what suits you, Art, it will work fine either way.

 

K

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The holes in the bearing plates are 3/8" ish. I cleaned mine up with a 3/8" bit and used 3/8" stainless bolts. 1/4 would work fine and you would have the advantage of a bit more wiggle room for shaft alignment. This is the only place that gave me any real heartburn, making sure the shaft was perpendicular to the tool arm mount. Measure 3 or 4 times...

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  • 4 weeks later...

Guys,

I finally took some photos and put them on PB.

KMG clone motor and remote control for VFD-

DSCN1676-1.jpg

DSCN1675.jpg

 

VFD enclosure both closed and open-

The lights in the front of the enclosure are to remind me that I have power to the different VFDs.

DSCN1680.jpg

DSCN1679.jpg

 

Ken, I sort of copied your arm bolt-

DSCN1672.jpg

 

In action- I don't know if this will play here. It did not, but when I clicked on it I went to PB and could play it. It is my first attempt at video so it is pretty bad.

th_DSCN1678.jpg

 

Still need some tooling for it. Will be making/buying them soon.

Regards,

Fred

Edited by Pelallito1
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