My idea for a low cost grinder, whatta think? (pics)

Hello All,


I have an idea for a square wheel grinder and I'm looking for some constructive
criticism to help direct the design.  I'm trying to offer an inexpensive
design that the typical home shop guy (gal) can use operating on a home
shop budget.
<center>


<img SRC="http://www.geocities.com/beaumontmetal/sq_wheel/rendered.gif" NOSAVE BORDER=3 height=401 width=551>


This is the basic concept for a 2 X 72 beltgrinder.</center>

Simply bolt the square wheel assembly to the front edge of your workbench.&nbsp;
Your motor can be mounted on a hinged plate/board so that it can fall back
to tension the belt. Maybe add a spring or clevis for more tension....?&nbsp;
I didn't draw the motor mounting/belt tension details.


Similar to <a href="http://www.caffreyknives.com/wilton.htm">Ed Caffrey's
page on his Wilton modifications</a> , I made the platen so that it is
interchangeable with different lengths and widths...and also adjustable.




<center>


<img SRC="http://www.geocities.com/beaumontmetal/sq_wheel/squarewheel.gif" NOSAVE BORDER=3 height=506 width=561>


These are the basic overall sizes.</center>

The&nbsp; two rollers are solid aluminum at 2.5 dia. Every thing else
is angle iron and aluminum plate.

I think I can offer this assembly for just under $200.&nbsp; You would
supply your own motor and fit it with a drive roller. (I can supply the
drive roller of your choice also).&nbsp; Bolt it all to the work bench
top, fiddle with the tracking by moving the motor around...and bammo! your
off and grinding.

&nbsp;


So whatta ya think?


add a tool rest?

Bag the whole idea?

stick with wheels only?

???

&nbsp;


Seriously though, please let me know your thoughts and ideas.


Truly,

Rob Frink

<a href="http://www.geocities.com/beaumontmetal/index.html">Beaumont
Metal Works</a>
 
Its a good start. There are a few things that I don't think would work out that well.
1. is using the weight of the motor for belt tension. I have seen this done only on a table saw witha V belt. And it seemd like the only plus to it was when the V belt was cold and stiff, the motor could bounce up and down until the belt got warm and softened up some. The grinding belt probably won't have that problem. And with everyone supplying their own motor, you never know what kind of tension they'll be putting on the belt. My friends have a few motors off of old grain augers that are made of cast iron and weigh well over 100 lbs. Thats to much tension.And it isn't convenient for changing belts. I think it would get old fast trying to hold the motor up with one hand and line up the belt on all three pulleys with the other.
2. Shifting the position of the motor to adjust tracking. I don't think that would give you fine enough control. All belts are going to track a little differently. Some don't track good at all depending on how well their made. And you want a good solid mount between the motor and the bench, which you can't really have if you need to be able to move it around.
If it were me, I would have the motor bolted down solid, and I would use one of the small pulleys for tension and the other small pulley for tracking. The one on top, just needs a jack screw added to one side to make it act like the pulley on a belt sander. Tighten it and it tilts the roller one way, loosen it and it tilts the roller the other way.
For tension on the bottom, you could either set it up so that it could be ratcheted up and down on a bolt just like the tension pulley, only both sides evenly move instead of only one. That way the roller stays square. Or you could have some type of lever to throw on it similar to the way casters work where you flip the lever and it puts the wheel down, and you can roll whatevers sitting on the casters around. then you flip the lever the other way and it picks the roller up.

------------------
It'll feel better when it stops hurting.
 
I think you will need some kind of spring or other tensioning device to allow for easy removal and replacement of the belt. Likely you also need some tracking adjustment.

But don't let those comments put you off. This is a great idea and I think the knife world needs some get started tools, plus used motors and plywood are cheap.

I could easily envision having two or three of these, each set up with a different contact wheel, small wheel, or platen. Neat!

------------------
Jerry Hossom
www.hossom.com
The Tom & Jerry Show
 
Rob Nathan here
I like the idea
the only problem I see is
the motor,it will get in the way
when you grind of to one side.
a better idea would be
to mount the motor in the back
with the drive wheel on the motor
and the plaent and contact wheel
in the front
If it was set up like that I will
buy one in a minute
 
T

Taz

Knifemaker / Craftsman / Service Provider
Joined
Apr 28, 1999
Messages
2,547
I was going to try a similiar idea, but got a grizz instead. I had the carcass of a 3x21 upright wet dry sander, I was going to do the same type of thing, but mount the contact wheel up higher, so the platen would be horizontal instead of vertical behind the contact wheel, like your homemade sander on your site, but with 3 wheels, instead of 2. this way you get the tension and everything. L6steel made something similiar with a 4x36 carcass, I think. For the motor problems, put a pulley on the drive axle and step pulleys on the motor and stuff to make it slightly variable speed and mount the motor below it, so it wont get as much dust going near it. Is this helping?
 
The only "opportunities" would be tracking adjustment and belt tension. It is a necessity to move the belt off of one side of the platen or the other. The motor should be rigidly mounted to provide smoothness. Believe me, if it ain't smooth, nobody would want it.

For grinding a blade a tool rest is not necessary. It would be nice to have in order true things up from time to time. Take a look at the Hard-Core tool rest. It is held in place by an allen set screw in a collar. It clamps on. I just loosen mine, swing it back underneath out of the way and tighten it back up. Its there when I need it, just loosen and swing it back out.

For all practical purposes, to flat grind, a setup conceptionally like yours is all that is necessary. You are on right track.....I am interested.

As Jerry Hossom stated, I would have a couple of setups like this in my shop in addition to what I have now to do different operations. This really looks good.

[This message has been edited by C L Wilkins (edited 09-03-2000).]
 
Just add an "idler,tensioner, tracking wheel" to the back of the gusset, the two small wheels are mounted on. my .02

------------------
Sola Fide
 
rfrink its getting there, put pulleys on both the motor and the grinder useing a fan belt, this helps smooth out the power transfer to the grinding belt also it
can make it variable buy having the tower on a seperate board what i do with my norman coote grinder is place the fan belt on the desired step pulleys pull the tower on the board towards me and clamp it from the side.


------------------
Laurence Segal www.RHINOKNIVES.com
 
I don't have enough experience to comment on the design much, although I'll echo that tracking needs to be easily adjustable and that, ideally, I'd like platen and contact wheel to be at similar height.

The other problem you might run into is cost. The Grizzly comes right now for $275 and that includes the motor and the buffing wheel. On the other hand hand, you may it rather easy to beat Grizzly at a little thing called 'service'.

I'll be watching with interest.



------------------
Rob Ridley
Ranger Original Handcrafted Knives
 
You beat Grizzly hands down in one area. Yours is made in Columbus, Ohio.

You also have the beginnings of a very flexible design that could easily be set up with whatever wheel or platen I wanted to have ready for my next task. Frankly, the idea of having a series of these on a bench is becomming more and more appealing as I think about it.

Please stick with this idea, and make it happen.

------------------
Jerry Hossom
www.hossom.com
The Tom & Jerry Show

[This message has been edited by GaKnife (edited 09-03-2000).]
 
Originally posted by rfrink:
Hello All,
I think it is a great design and with some refinements, say for speed adjustments and tracking controls you or on to a winner here.
I am happy to see that the Inventing community is alive and well instead of sitting in from of a plastic box and pushing
the remote control.


I have an idea for a square wheel grinder and I'm looking for some constructive
criticism to help direct the design.  I'm trying to offer an inexpensive
design that the typical home shop guy (gal) can use operating on a home
shop budget.
<center>


<img SRC="http://www.geocities.com/beaumontmetal/sq_wheel/rendered.gif" NOSAVE BORDER=3 height=401 width=551>


This is the basic concept for a 2 X 72 beltgrinder.</center>

Simply bolt the square wheel assembly to the front edge of your workbench. 
Your motor can be mounted on a hinged plate/board so that it can fall back
to tension the belt. Maybe add a spring or clevis for more tension....? 
I didn't draw the motor mounting/belt tension details.


Similar to <a href="http://www.caffreyknives.com/wilton.htm">Ed Caffrey's
page on his Wilton modifications</a> , I made the platen so that it is
interchangeable with different lengths and widths...and also adjustable.


<center>


<img SRC="http://www.geocities.com/beaumontmetal/sq_wheel/squarewheel.gif" NOSAVE BORDER=3 height=506 width=561>


These are the basic overall sizes.</center>

The  two rollers are solid aluminum at 2.5 dia. Every thing else
is angle iron and aluminum plate.

I think I can offer this assembly for just under $200.  You would
supply your own motor and fit it with a drive roller. (I can supply the
drive roller of your choice also).  Bolt it all to the work bench
top, fiddle with the tracking by moving the motor around...and bammo! your
off and grinding.

 


So whatta ya think?


add a tool rest?

Bag the whole idea?

stick with wheels only?

???

 


Seriously though, please let me know your thoughts and ideas.


Truly,

Rob Frink

<a href="http://www.geocities.com/beaumontmetal/index.html">Beaumont
Metal Works</a>
Click to expand...

 
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