PA Multitool Belt Grinder on Craftsman Block Grinders

McBrownie · Dec 26, 2014

This thread is about installing a PA Products Multitool Model 362 belt grinder on two different Craftsman block grinders. The two are a 3/4hp 397.19670 from the late 1960's and a 1/2hp 397.19591 from the early 1970's. Both of these block grinders are commercial/industrial capacitor start "round tops". The manufacturer does not recommend using a grinder with any less "oomf" than these and I agree with them. The 1/2hp, while still fine, struggles a little more starting up than the 3/4hp. Once running, they are both plenty powerful and smooth running.

The 3/4hp 397.19670
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And the 1/2hp 397.19591
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McBrownie · Dec 26, 2014

First of all, my thoughts on the Multitool MT362 manufactured by PA Products. I'm not going to go into a full product review as you can find those on Youtube, etc.. I will go into the build quality and more specifically, how this thing bolts up to an old Craftsman block grinder. Let me jump to the chase - you will need some extra parts to get this installed. At a minimum, new bolts and something to make a spacer. I used plywood at first and then had one made from aluminum once I figured out what I needed. I'll get into that later.

If you are looking for something that will be used all day, everyday, you need to look at a better, more purpose-built machine. Burr Kings, and the like, cost thousands of dollars for a reason. But, if you want something that brings a smile to your face when you sharpen up your lawnmower blades or grind away on some brackets or bolts, then give this some serious consideration. For $250, assuming you already have a good enough grinder to mount it on, it is a fun machine to have in your garage or workshop. The side table is an additional $75, by the way. If you don't already have a high enough quality (and powerful enough) grinder, then you might want to look into a complete Kalamazoo unit or something along those lines. The bottom line is I'm really am glad I got this attachment.

Moving on. I give the overall build quality of the multitool a "B" as I had to do some things that should have been done by the manufacturer. I'll get into that as I go along.

The kit comes with a nice box full of hardware, which I promptly replaced:
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Other than the offset washer and the bushing, plan on throwing this out and buying new. $10 on decent nuts and bolts will save you considerable frustration. These bolts are so soft that they deform and are almost single-use. Here is the new stuff, along with some of the original washers. You can see one of those little sheet metal screws that are supposed to be used to attach the side cover.
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I drilled the 6 holes a little deeper and tapped them for 3/4" 10-24 screws. Again, stuff that should be done by the manufacturer, but would drive the price up.
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The side plate where the sanding disc mounts isn't flat. I ordered a piece of 1/8" aluminum to replace this stamped steel.
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So, enough griping about details, let's get into getting this thing fitted to a block grinder or two.

McBrownie · Dec 26, 2014

Of all of the steps in the instructions, this measurement is the most important. The inside edge of the aluminum drive wheel should be approximately 1/4" from the adjustable bracket that maintains the alignment with the front contact wheel. Mine is at 3/16" which is close enough. If I had a lathe, I might take another 1/16" off of my spacer to get this gap right at 1/4", but it is ok as it is.
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Having it at 1/4" will give you plenty of room to adjust the front contact wheel to allow the belt to track properly and will allow the drive wheel to stand clear of the guard like this:
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By the way, I repainted the guard to match my grinder. It was originally black. Here is the problem and this was the case on both the 3/4hp 5/8" shaft and 1/2hp 1/2" shaft. Without a spacer, and with the bracket bolted up to the grinder like the original wheel guard would be, the drive wheel sticks out like this:
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The reason for this is that on both models, the shaft steps up to .667" and the hole in the aluminum drive wheel is only .625"
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This makes the wheel only go on to the smaller diameter (either 5/8" or 1/2" with a bushing) up to the point where it steps up to .667" which leaves it sticking out too far. So, now we have 3 options:

1) Drill out the hole in the aluminum drive wheel to something bigger than .667"
2) Machine down the rotor shaft to .625"
3) Move the mounting bracket out away from the grinder with a spacer so it stands out as far as the drive wheel.

Problems with options 1 and 2, other than being irreversible, are that the aluminum drive wheel still needs something solid to bolt up against. Also, if you could slide the drive wheel further onto the shaft, you might not be able to install the side plate for the disc sander. The shaft would be proud of that surface.

My first plywood spacer allowed me to utilize the original snap ring that exists on the 5/8" shaft models. In order to use that, I needed a 1-1/4" thick spacer that I made out of plywood. It's not pretty, but it worked.
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This solution presented another problem. Using the small surface of the "circlip" made it darn near impossible to get the drive wheel running true. I needed something more solid.

That is when fellow GJ'r exmaxima1 came up with a great idea.

McBrownie · Dec 26, 2014

Here is where the measurements start getting confusing. The thickness of the mounting bracket is just under 1/4"
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The .667" diameter protrudes a little under 1-5/8" from the bracket on the 3/4hp 5/8" shaft:
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and a little under 1-1/2" on the 1/2hp 1/2" shaft:
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An 1/8" difference between the two models, but the same spacer worked on both.

So, here is the idea that exmaxima1 had. He suggested using a shaft collar to give the aluminum drive wheel a better surface to bolt up to. But, I couldn't use just any shaft collar. I needed one that would fit a .667" shaft. exmaxima1 made one by opening up a standard 5/8" shaft collar I.D. with a lathe.

Edit: GJ'r JZiggy simplified this step by getting a 17mm shaft collar. Saves a machining step. http://www.garagejournal.com/forum/showpost.php?p=5520533&postcount=32

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The thickness is a little over .400"
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And here it is installed on the 3/4hp 5/8" shaft:
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And on the 1/2hp 1/2" shaft with the supplied bushing:
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I tried to get the shaft collar up as close as possible the mounting bracket without it rubbing. That is why it is possible to use the same spacer even though the shaft dimensions are a little different.

So, what about this spacer?

McBrownie · Dec 26, 2014

Previously, I showed my 1-1/4" plywood spacer, but that just wasn't going to cut it. Taking all of the dimensions into account, I settled in on 7/8" being the magic number. Depending on the washer you use, or don't, you could get by with all sorts of different thicknesses. I wanted to try to keep it as thin as possible.

A drawing of what I had made:
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And the finished product also made by exmaxima1. It is aluminum and has been painted:
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I checked the runout on the shaft collar with a dial indicator an it had .002". That was resulting in .020" runout on the outside lip of the aluminum drive wheel.
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Figuring I could do better, I made a shim out of folded aluminum foil and placed it between the shaft collar and the drive wheel on the "low" side.
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And the finished result with the shim and a little tapping with a soft faced hammer is only a little over .002" runout at the edge of the of the aluminum drive wheel. I'm very happy with that.
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You can do the same thing with a pencil if you don't have an indicator and here is a great write up by Don Geiger about how to do just that.
http://www.geigerssolutions.com/Tuning-Up-a-Bench-Grinder.html

Here it is installed with new, longer, grade 8 bolts.
View media item 46341
While I was repainting this grinder (the day after starting this thread), I did something that will make the installation mounting bracket easier. Finding the right length bolts to hold the bracket to the motor housing was a bit tedious. I would end up with bolts that would fit in 2 out of 3 holes. I couldn't just add washers because then the bolts heads would run into the shaft collar. I ended grinding them to lengths that worked. But, since I had the grinder apart, I tapped the holes all the way through the casting. They are 1/4-20 and we're only partially threaded on my grinder. I would NOT do this unless you have the grinder apart. I don't think it would be a good idea to have chips from the tap floating around inside the motor. It does make assembly easier and is worth doing if you are going to have your grinder apart anyway.

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McBrownie · Dec 26, 2014

So, that is it for now. I am contemplating a better way to move this unit from horizontal to vertical and back. As it ships, this involves loosening and tightening 3 bolts and also sometimes messes up the alignment. If I do something with that, I'll update this thread.

Here are some other things that I had to tweak on this unit:
The side table miter is cast aluminum. This presented two issues. The numbers were impossible to read and the face was not machined meaning that it was not flat and not square. Some time with a file solved that:
View media item 46339
After some paint and lightly filing over the numbers to expose the bare aluminum. Then a coat of clear
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The platen also had some irregularities in it. I filed that down flatter as well. I have heard of some people attaching glass to their platens. There is room to do it on this unit and might be something I consider in the future:
View media item 46337
The mounting bracket was a rough cast aluminum part. After some belt grinding and paint. Yep, I used to the multitool to build the multitool.
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Another angle showing the side table:
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Again, I like this tool and I'm glad I got it. I'm sure there are other ways to get around this spacer issue and would like to hear your ideas.

torqueman2002 · Dec 26, 2014

Subscribed, looking forward to your posts!

As usual sir, your post is very detailed, well documented, and painstakingly thorough.

drivesitfar · Dec 26, 2014

McB: i really like how thorough your posts and threads are. i always learn something when i see the awesome pictures with your description. so i'm guessing you are going to leave your multy tool set up permanently on the 3/4 HP Block grinder. yes???

other than your time how much have you invested in this set up? i think you mentioned you paid $200 for the belt grinder attachment. then bought new nuts and bolts. then where did you find or buy the sanding disk attachment?

very nice and anytime you get a chance to show this machine running on a Youtube video and sharpening up a lawnmower blade or anything you choose to work on that would be great.

thanks for posting all this work

McBrownie · Dec 26, 2014

drivesitfar said:
McB: i really like how thorough your posts and threads are. i always learn something when i see the awesome pictures with your description. so i'm guessing you are going to leave your multy tool set up permanently on the 3/4 HP Block grinder. yes???

other than your time how much have you invested in this set up? i think you mentioned you paid $200 for the belt grinder attachment. then bought new nuts and bolts. then where did you find or buy the sanding disk attachment?

very nice and anytime you get a chance to show this machine running on a Youtube video and sharpening up a lawnmower blade or anything you choose to work on that would be great.

thanks for posting all this work

Thanks Drives and yes, the 3/4hp is the right machine for the job. I've never done a YouTube video. Something that I'll have to look into. So, how much do I have into it? Too much!!!

The Multitool itself was $199 with free shipping and i threw in the starter belt kit for another $50 from:

www.trick-tools.com

The side table is found on the "Accessories" tab for the MT362 and it ran another $75. Then add $30 for the spacer, shaft collar and new hardware and I'm at about $355. If you get one of these combined with a new 1hp Jet grinder, it is $420. Throw in the belts and side table and that goes to $545. However, I think when you start approaching the $500-$600 mark your options start opening up for some more serious equipment. I'm not sure the Multitool can keep up with those bigger dogs. But, it is cool looking on an old Block!

McBrownie · Dec 27, 2014

I updated Post #5 with some information that will make the installation easier. It involves tapping the holes in the motor housing and makes attaching the multitool bracket easier. I would only suggest doing this if you have the grinder apart. Mine is all painted up and I'll post a finished picture when I get it back together.

McBrownie · Dec 28, 2014

Another update to Post #5 showing how I shimmed the shaft collar to reduce the runout on the aluminum drive wheel from .020" to just over .002". I also added a link to Don Geiger's write up on tuning a bench grinder.

nine4gmc · Dec 28, 2014

Great job McB! That thing looks awesome with all the functions it has! One suggestion for not having to add the spacer, have the armature shaft turned down on a lathe the exact length of the space needed for it to line up.

drivesitfar · Dec 28, 2014

Nines: i think McB already mentioned that was a permanent fix, but then he would lose the option of taking off the extension off of the block and turning it back into a regular block later.

McB: have you named it yet because Blockerminator doesn't seem to work for me? have you used the side sanding feature yet?

i haven't made a you tube video yet either. I'm sure our kids are able to do it so maybe we should ask them to help us make one the first time? yours would be viewed as college GJ forum standards as detailed as you are.

nine4gmc · Dec 28, 2014

My bad, I missed that but I think you could sleeve it if you ever wanted to go back. :dunno:

drivesitfar · Dec 28, 2014

Nines: i'm guessing if McB uses this enough it will never have the option of changing back, but he already had EX make a sleeve and redrilled and retapped the holes. your thinking was and is usually pretty right on.

by the way did you ever hear back from the Reed 108 owner and post on your thread or the vise thread if you have more pictures or if it found it's way into your shop.

McBrownie · Dec 28, 2014

Drives,

Maybe BlockMeister will catch on.

Here are some of the finished pictures. Phase 3 is done!
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View media item 46455
And yes, I tried out the side table. Works pretty nice!

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It feels good to have it done. Repainting these 8-inchers is a huge task. Took me most of a day! I'll post a picture over on the block grinder thread as well.

jakemac · Dec 28, 2014

That set-up sure is going cause a stir when it's time for the Estate Sale. :lol_hitti

It's a work of art. :drool:

McBrownie · Dec 28, 2014

Thanks Nines! Machining down the rotor shaft is an option and, like you said, you could use a sleeve to go back to original. I didn't have the means to do that and once you do, you can never undo it. The hardest part of the installation was figuring out the width of that spacer. I think you could get by with .750. One thing I didn't mention above is that I didn't use the offset washer like they show in the instructions. I used in on the outside of the wheel, not the inside like they recommend. When I put it on the inside, it pushed the drive wheel even further out causing more of a problem.

McBrownie · Dec 28, 2014

jakemac said:
That set-up sure is going cause a stir when it's time for the Estate Sale.
It's a work of art.

Hopefully in 30 years! :beer:

McBrownie · Dec 29, 2014

Chalk this up in two categories:

1) Me going a little more overboard with this build
2) Something that should have been included in the miter table kit in the first place

It is a "T Slot Linear Bearing Brake P/N 8020-6800" and fits like it was made for this table. It's all metal and replaces the 5/16 nut that locks down the table angle adjustment. Having a handle makes angle adjustments 100x easier since you don't have to fumble with a wrench or ratchet.

View media item 46485

jakemac · Dec 29, 2014

You lied, you said that you were done. :lol_hitti

McBrownie · Dec 29, 2014

jakemac said:
You lied, you said that you were done.

Jake,

Guilty as charged! Actually, I forgot I had ordered that part.

1950mercury · Dec 29, 2014

drivesitfar · Dec 29, 2014

McB: another nice addition. very cool piece. by the way do tell what the new Avitar is? i'd guess it was a Ritzblitz handle, but it's too old looking so did you shine that up on the Blockmeister?

sgs236 · Dec 29, 2014

That is one of the best and most detailed write ups that I have read in a long time. Outstanding job on the finished product.

McBrownie · Dec 29, 2014

Thanks Merc and Sgs!

Drives, That is a picture from the write up of my Parker 203 I did on the Vises 101 thread a while back. It's all original, almost 100 years old, and was a rusty pitted mess when I got it. It took me a few weekends to get it looking like that. I'll bet The BlockMeister could knock it out in less than an hour. I'll have to get another rusty vise just to verify that. :beer:

the gypsy · Dec 29, 2014

Hi McBrownie. I would like compliment you on your work. It is a beautiful piece and I am quite certain a joy to work with. Keep up the good work and the write-ups.

It never ceases to amaze me, the quality of workmanship on this forum.

Trey T · Dec 29, 2014

beautiful machine!

LXCam · Dec 29, 2014

Most excellent job there Mr. McBrownie!. Ya you got a little more into it then would normally make sense, but it's a one off "done it meself" thing of beauty!.

exmaxima1 · Mar 2, 2015

McBrownie said:
Thanks Nines! Machining down the rotor shaft is an option and, like you said, you could use a sleeve to go back to original. I didn't have the means to do that and once you do, you can never undo it.

It's raining here in Hilo, so I was re-reading some old threads while the beer chilled. The more I think of it, you could turn the shaft down to .625 as suggested, and install a stock size shaft collar anywhere on the shaft if you ever want to revert back to a grinder. A collar is surely better than the crappy snap ring that was original. In fact I might try that on the 3/4hp block I have laying around.....sometime after vacation....

McBrownie · Mar 2, 2015

exmaxima1 said:
It's raining here in Hilo, so I was re-reading some old threads while the beer chilled. The more I think of it, you could turn the shaft down to .625 as suggested, and install a stock size shaft collar anywhere on the shaft if you ever want to revert back to a grinder. A collar is surely better than the crappy snap ring that was original. In fact I might try that on the 3/4hp block I have laying around.....sometime after vacation....

Ex,
I agree that a shaft collar is way better than the snap ring. But, isn't it way easier for you to sell the "machined shaft collar and spacer combo kit" than providing a machining service for rotor shafts?

Trey T · Mar 3, 2015

I have a 1/2hp 257.191401 (early 80s), is it a good candidate for the mod (understood 3/4hp is recommended)?

exmaxima1 · Mar 3, 2015

McBrownie said:
Ex,
I agree that a shaft collar is way better than the snap ring. But, isn't it way easier for you to sell the "machined shaft collar and spacer combo kit" than providing a machining service for rotor shafts?

I wasn't looking at it from that perspective. I assumed that someone else would be doing the machining. Absolutely, a spacer kit is easier for persons without a lathe :thumbup:

Heading back to the Midwest today---bummer....

GirchyGirchy · Mar 3, 2015

That's pretty cool...just wish it was a little cheaper!

McBrownie · Mar 3, 2015

Trey T said:
I have a 1/2hp 257.191401 (early 80s), is it a good candidate for the mod (understood 3/4hp is recommended)?

Trey,

That is a split-phase model. I know because I own that exact same grinder! I never tried installing the Multitool on that model. The spec says "1/2hp and higher" so it should work. I may try installing it when the weather warms up (or should I say "if the weather warms up). If I do, I'll update this thread with my findings.

McBrownie · Mar 3, 2015

GirchyGirchy said:
That's pretty cool...just wish it was a little cheaper!

I agree. If it was, I might get two! But, that fact is that you can change belts so fast that it wouldn't make sense to have two. Then again, there is no award given for making sense. :lol:

McBrownie · Mar 5, 2015

Just an FYI, the 2x48" Multitool is on sale this month.

http://www.trick-tools.com/Multitool_2_x_48_inch_Belt_Grinder_Attachment_MT482_307#.VPjcxfnF-y4

Disclaimer: I don't work for Trick Tools or Multitool. I just got this in a customer email and thought I would pass along the info.

Trey T · Mar 5, 2015

^Is that what you used or the 2"X36"?

McBrownie · Mar 5, 2015

Trey T said:
^Is that what you used or the 2"X36"?

I used the 2x36 because it was $80 cheaper at the time. However, 2x48" belts are much easier to find than the 2x36". On sale, it's still $50 more. I don't use it enough to justify the difference. If I was using it everyday, then I would definitely go for the 2x48 because of having more options for belt suppliers.

torqueman2002 · Mar 6, 2015

McBrownie said:
I used the 2x36 because it was $80 cheaper at the time. However, 2x48" belts are much easier to find than the 2x36". On sale, it's still $50 more. I don't use it enough to justify the difference. If I was using it everyday, then I would definitely go for the 2x48 because of having more options for belt suppliers.

McB - How very timely your post is. :thumbup:

Yesterday I was thinking what should I do with a Block or 2 that need wheel guards and/or covers. :headscrat

Then it hit me! A McB style BlockMeister.

Thank you for enabling the Torqueman.

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