KMG Grinder Tweaks Thread

Tait

Tait

Joined
Sep 26, 2009
Messages
576
Hi all,

I have done a couple of tweaks to my KMG grinder which I have found useful; I thought I'd share them for others, and see if anybody had any to share back.

1) Raise it above the workbench a bit. Many folk set up their benches so the grinding is performed just off the edge. I have a 30" wide workbench, and the KMG sits back on it because stuff has to be stored in front of it when I'm not using it. So my 10" contact wheel is - or was - pretty close to the workbench surface. Last week, I cut an 18.5" square piece of solid core door and put it under the metal baseplate. This raises the grinder up almost 2", which is, for me, a more comfortable grinding height. It is also high enough to fit a bread pan with water underneath the contact wheel.

2) Move locking lever from left to right hand side. The lever used to lock arms in place was always pretty awkward for me. I don't have an MAP arm (yet), but I saw how the grinder pieces can be assembled such that the handle lock is on the right hand (belt) side of the grinder. This is a much more natural operation as I can easily push down the tension lever with my left hand, extend the attachment to take up slack with my right hand, then lock the lever with my right hand. Doing this does change the alignment of the tool arms a bit, but is still well within tracking adjustment capability.

Any other "hacks" for the KMG out there?
 
I used square tube to make a tooling arm for each attachment. They cost like 5 bucks each instead of 80 for the kmg arms. Works great.
 
Fellhoelter said "Fixing the damned tensioner arm was Priority 1 for me."

What was wrong with the tensioner arm?
 
It's awkward, and short.

You get a lot more leverage if it's extended.

DSCN2432.JPG


I also put the arm locking screw on the right hand side on day 1
 
I agree on the arm lock screw. Going on the outside. Much more graceful two handed operation. I can switch belts in seconds.
 
fellhoelter what kind of platen you got going on there?
I set mine up with a DC motor I really like it a lot. It sounds like it is about to take off.
 
It's the super deluxe, watercooled, flatgrinders special platen!

Belt rolls over a 3/16" radius and runs parallel to the cutting edge.

It only takes a few minutes of hand sanding to get a nice satin finish once I come off of this @ 400 grit.
This does the bulk of my work for me, and plunges are always dead nuts, with a nice radius.

As you can see, I've modified the tensioning arm, the locking screw, and the tracking knob on mine.
And after 2 years of using it, I discovered the wheels were not all on the same plane, and that's why I had some pretty bad belt wobble.
Got the centerlines all coplanar, and the wobble is gone.
 
Have to agree with the extended tension arm. This is from a build about 2yrs ago.
Also, gas shock rather than the compression spring :)
Don't regret either.

HPIM4410.jpg
 
I've seen tool rests that adjust their angle with just 1 bolt to adjust angle. Not cool like mapp but quick and effective.
 
Some great ideas!

Fellhoelter, I particularly like your platen! It looks like it's about 6" wide by 10" long? Is the vertical "just" bolted to the tool arm?

I've been saving up for a disc grinder - this might do some of what the disc grinder does. Do you also have a disc grinder?

Tait
 
Yep, the vertical is just bolted there.
And through it and the 2 piece platen, the water flows in and out.

I do have a disk.

It dovetails bolsters, and nothing else.
 
Fellhoelter said:
I discovered the wheels were not all on the same plane, and that's why I had some pretty bad belt wobble.
Got the centerlines all coplanar, and the wobble is gone.
Click to expand...

Brian, I also got some wobble and my tracking wheel is very tilted to be able to get the belt tracking in the center of the contact wheel.
Any tips on how to achieve that coplanar centerlines thingy? I have no idea where to begin to look. :confused:
 
It's hard to explain it all, since it was actually a pretty big procedure.

Since there are no dowels or anything in the build, and the screw holes are oversized to allow the screws to fit, the whole machine wasn't square.

I started by making sure the receiver for the arm was actually square to the drive wheel.
It wasn't, so that took some creative adjusting and measuring.
This is an important step, because otherwise the drive and driven wheels end up with axis that are not parallel with each other. something like this \ |
They need to be parallel, more like this ||
Hope that's clear, because it's the key.

Once that was done, and I was sure the axles weren't cocked in relation to each other, I put the tracking wheel in a neutral position, and took a measurement off of it.
Again, no easy task, I had to get creative.

I then made sure the centerline of the drive wheel was on the same plane as the tracking, and did the same for the wheels on all the tooling arms.

All was better after that.

Maybe a drawing will help a little.

Screwy_Tracking.jpg


This is looking straight down on the grinder, it's just the wheels.

You can see on the right, what I started with.

The wheels were crooked in relation to each other, and the centerlines didn't all line up.

The left, is what you want.
 
By the way, I discovered all of this, when I built my own grinder.

I made a 3 wheel grinder that tracked like a dream, and when I moved the belt to the KMG, it wobbled all over the place.
Same belt, 2 machines, 2 different results.

I investigated, and fixed it.

It seems like when the wheels are crooked to each other, the drive wheel is trying to drive the belt off of the contact wheel/platen/slack belt.
It only gets so far before the tracking wheel overcomes it, and brings it back.

Diving off and coming back = Wobble

At least that's today's theory.
 
Fellhoelter,

The water cooling seems like a lot of work - did you find it was necessary, or was it sort of just for fun??

I'm thinking of making a similar platen - is it possible to get a copy of the plans? (Or better yet, do you want to make one for me?)

Tait
 
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