The second iteration of my grinder design (more pics)

rfrink

rfrink

Joined
Aug 1, 2000
Messages
863
Hello Again,


Thank you all for the input on my&nbsp; <a href="http://www.bladeforums.com/ubb/Forum51/HTML/001370.html" target=_blank>first
grinder posting</a>!&nbsp; I carefully read them over and over. "Thank
you"&nbsp; to those who emailed photos and faxed parts lists and exploded
views of various grinders.


I just can't believe the prices for some of the grinders on the market
and it makes me think that there has to be another way than to dish out
$1000-$2000.
<center>


Based on input,&nbsp; I've come up with the second iteration.


<img SRC="http://www.geocities.com/beaumontmetal/sq_wheel/frame.gif" NOSAVE BORDER=3 height=415 width=705></center>

It starts with a basic frame made of commonly available steel pieces
bolted to a heavy workbench top.&nbsp; The riser plate (mounted between
2 angle irons) accepts a contact wheel setup or a square wheel setup. The
arbor for the contact wheel is shown in red above. The belt tension arm
is spring loaded and adjustable in length to accommodate different setups.&nbsp;
The tracking mechanism was basically copied off of a band saw which has
an adjustment knob to tilt the idler wheel, shown below.
<center>


<img SRC="http://www.geocities.com/beaumontmetal/sq_wheel/tracking.gif" NOSAVE height=157 width=223>


Here are some clickable links to view more:

(they should open up in a new window for convenience)


<a href="http://www.geocities.com/beaumontmetal/sq_wheel/square1.gif" TARGET=_blank>square
wheel setup</a>

<a href="http://www.geocities.com/beaumontmetal/sq_wheel/squarsetup.gif" TARGET=_blank>square
wheel details</a>


<a href="http://www.geocities.com/beaumontmetal/sq_wheel/contact1.gif" TARGET=_blank>Contact
wheel setup</a>

<a href="http://www.geocities.com/beaumontmetal/sq_wheel/10contact.gif" TARGET=_blank>Contact
wheel details</a></center>
http://www.geocities.com/beaumontmetal/sq_wheel/10contact.gif


I think I've overcome some of the major downfalls of the first design
and still kept this one simple enough that many people can build it at
home.&nbsp; Let me know all of your thoughts and if everything looks OK
I'll start building one to play with.


Sincerely,

-Rob


<a href="http://www.geocities.com/beaumontmetal/index.html" target=_blank>Beaumont
Metal Works</a>
 
Great idea for the tracking idler wheel set up!!! Will you be including a 10" rubber covered contact wheel???

------------------
Always think of your fellow knife makers as partners in the search for the perfect blade, not as people trying to compete with you and your work!
http://www.nebsnow.com/L6steel
Buzzards gotta eat, same as worms!!!
 
Great!! I like it a lot. You might consider going with a common shaft hole in the riser plate that would let the user employ the standard wheels they may already own. My Square Wheel Grinder accomodates any wheel or accessory with a 3/4" shaft. That way, I would dump that loud and nasty old beast and get three of your setups, one each for the square wheel, the contact wheel, and a small (3/4") wheel. Each of those would likely want a different drive wheel(s) for its optimum speed. I could also select the motor depending on the power I need for each setup.

Lots to like about this.

------------------
Jerry Hossom
www.hossom.com
The Tom & Jerry Show
 
Looks good to me.
biggrin.gif

I have a homebuilt grinder, that I changed so many times, I named it the Thunderbolt Grease Slapper. I ran out of steel for the motor mount so I just screwed the motor to the workbench with sheetrock screws.
That isolates the vibration of the motor from the contact wheel.


------------------
Sola Fide
 
D'oh! I should have done this a while ago, but you beat me to it. Oh, well, I'll have to find some other outlet for my engineering genius!
rolleyes.gif
Anyone have any ideas of some engineering that needs doing, so I can afford even more knives?
smile.gif


Okay, on your grinder, the only thing I would change is to separate the motor from the grinding belt with a drive belt of some sort. That would allow lower-cost motors, which might have too much vibration if in direct contact with the belt, to be used, as the drive belt would serve to isolate the grinding belt from the vibrations. Plus, by using multi-size pulleys, you could change the belt speed easily. Just my thoughts, anyway.

--JB



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e_utopia@hotmail.com
 
Let me know when you start making these. I'm still looking for that "perfect, low-cost(not cheap) home shop knife grinder. You have a great idea here. Good job!
 
its looking good! i have two points on the design, running the belt right off the motor will put to much vibration in to the grinding belt unless your just using it with a 50 grit belt as a hogger doing profile work. two it is easy to adapt it to variable by mounting the riser on another board and putting it flush with the edge of a home work bench so you can use a step pulley and C clamp for variable adjustment. good luck

------------------
Laurence Segal www.RHINOKNIVES.com
 
Rob, your illustrations and drawings are great, what software are you using to make them?
 
Tanker,
thank you for the kind words! I used CADKEY99. It is a low cost but highly functional package. The main reason I like it is that it makes solid modeling a snap. Once the model is built, all the renderings, views, layouts just fall out. If you update the model, all of the layouts update automatically...even dimensions.

By the way, software is boring......get in the shop and make something!...heh,heh, heh.

seriously, thanks again!
-Rob
 
Rob
I think your grinder Ideas have merit but you may be trying to be to thrifty.
As Jerry and Lawrence stated you should have a universal type mounting hole for platens and wheels and seperate the motor from the belt.
This is my grinder to give you some Ideas. Play with this design on your cad system. I have seen a few others like it but each a little different. The basic frame cost me about $65.00 Can. I figure I have about $350.00 Can ito it as it sits including motor and contact wheel. Not bad for a variable speed grinder. I can slow it down so that I can read the print on the back of the belts or run it so fast I leave the room as it winds up for take of.
View

View

Incorperate some of your ideas into this please, as I am starting to build anouther one and would appreciate any new ideas.

------------------
Robert
Flat Land Knife Works
rdblad@telusplanet.net
http://members.tripod.com/knifeworks/index.html
 
The tension and tracking adjustment arm may pick up enough viberation that will need to be beefed up or another support arm.

Looking good!

Lynn
 
rob, i've designed a belt sander, and the biggest problem is vibration. it looks to me like the tracking tension wheel would put out aot of vibration becuase of the arm.
the other thing is that you need a thick steel base not wood. steel will stay flat and true, and wood will warp causeing tracking problems.
i used a 1 1/2" thick steel plate, but you don't have to have it that thick., i'd say 1/4" would be good enough.
 
Magnum,
A friend of mine built a home built grinder and it is just as smooth as my Hard-Core, no vibration . What kind of a setup/design do you have?
 
I'm back to the ol' drawing board. I agree with the points about the tension arm not being stiff enough.....heck it looks pretty flimsy sticking out there now that I look at it again. I also like the ideas about a stiffer base plate plate and trying to commonize the "business end" of the grinder to accept the contact wheels that you might already have.

I've got a new design now that is looking very good! Belt drive, beefy construction, simple, very robust tensioner and tracker, flexible, variable speed..?

I hope to post it before the end of the weekend for everyone to review. Also, I'm looking into a infinitely variable cone pulley system. Not step pulleys. I'll post more as I figure out the details. I learned that MTD uses one on a riding mower for speed control. The dealers quoted a price of about $65. Is it smooth, quiet, reliable...?...I dunno...but I'm looking into it. Anyone seen these or used them?

Anyway, Thank you again for the input..(I used it all).

Sincerely,
Rob
 
Rob,
Have you thought of driving off of the contact wheel instead of a drive wheel off of the motor? A couple of pulleys and a belt are far less expensive than a drive wheel on the motor. Fewer tracking problems that way, believe me. If the design is using the minimum number of wheels, the less chance of tracking problems.

As far as having a contact wheel and flat platen, that would work as well. Just have the contact wheel on the bottom.

I personally would be more interested in just a flat platen machine with rubber covered wheels to minimize vibration and enhance smoothness. That is just a personal preference though.
 
cl,
i built my grinder based on the two wheel style. the front wheel is the drive. right know i'm using a platen, i plan on switching to a 10" smooth contact wheel. it will be the drive wheel.
i don't like having a separate drive wheel, it's just a added expense.
my grinder wieghs about 600lbs.
i don't get much vibration from it though, and i use a bigger belt the 3"x132"
 
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