2 X 72 Grinder - Home Built

[bpOutdoors]

Here is a recent home built grinder from a good friend who is gearing up to make knives...


[video=youtube_share;Vd356Bfh-fc]http://youtu.be/Vd356Bfh-fc[/video]

 

[Bill Hoffman]

Very nice. Just make sure you keep the motor as grit-free
as you can. Open frame motors ingest grinding dust in the
blink of an eye and metal dust in an electric motor is never
a good thing.

Bill

 

[12345678910]

When I look at the image at 2:02

The shaft seems small - what size is it ?

At the drive wheel, the shaft sticks out a long ways unsupported

I would have tried to put the bearings farther apart and closer to the drive wheel.
It seems like it will bend easily, then it will be very unbalanced.

 

[Atlas Knife Company]

+1 on the count's suggestion about the pillow blocks. Is the drive wheel 5-6" from the pillow blocks? That's a LONG ways for the shaft to support.

What's the purpose of the plate on the "wheel attachment arm?" You lose the rigidity of the square tube when you move to a flat plate. Most grinders that I can find pictures of have the wheel bolted directly to the tube. This would give the bolt two attachment points instead of just one.

The tension spring looks very light. What is it rated for?

Why 4 slots, and why so far away from the wheel slot? I can't find any grinders that have tooling slots that far from the main slot.

Here's a picture of what I mean about the location of the slots and the platen bolted directly to the tube. Also, check out the toolrest, very little flex or wasted metal in it's location.

 

[quint]

Zaph its pretty much the NWG welded together with a few small changes. In that design the point to moint the arm is basically where he has it just right above it. I agree with ya just saying thats how they are made or should I say the designs call out for.


Bp looks good, I assume thats a 5/8" shaft, should work fine (I have the 3/4" one myself). One thing I use to have my pillow blocks setup like you did except my motor was farther away but even then it puts a huge amount of stress on the bearings which depending on where you get the blocks are probably imported stuff and not the good kind. If you take a 4x8 or whatever size you need, weld that on the top of your 4 tube box then mount the bearings it really helps with stability and evening out the stress.

 

[bpOutdoors]

> I believe the shaft is 3/4 but will have to check... it is at a friends home...

> Re: At the drive wheel, the shaft sticks out a long ways unsupported.
I agree... the plans show it this way so we will see how well it holds up but those bearings would be better located farther apart to mitigate shaft bending.

Thanks for the comments.
bryan

 

[bpOutdoors]

> Re: What's the purpose of the plate on the "wheel attachment arm?" You lose the rigidity of the square tube when you move to a flat plate. Most grinders that I can find pictures of have the wheel bolted directly to the tube. This would give the bolt two attachment points instead of just one.

I think you have a good point here.. The plate is part of the plans but it might be worth looking into leaving them off and using a longer bolt for the wheel attachment throught the tube.

> The tension spring looks very light. What is it rated for?

I don't have numbers on the spring ratings but I think it was improvised from a hardware store visit. Just trying to see what works at this point.

> Why 4 slots, and why so far away from the wheel slot? I can't find any grinders that have tooling slots that far from the main slot.

Sounds like another good point.. will see how it performs and adjust accordingly.

Thanks again for all the feedback.

bryan

 

[Atlas Knife Company]

OK, all that aside, it looks like some nice craftsmanship and quality welding! I love the t-handles. I'm going to have to built a couple of those to replace the plastic handled junk that I have now.