Grinder construction questions

A

aarolar

Joined
Mar 21, 2010
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I am fixing to commence construction of my grinder and have a few questions. On the no weld grinder plans the motor mount plate is hinged what exactly tensions the belt or do you just rely on the weight of the motor to provide tension? (step pulleys being used) Second, what is a simple cheap way to make your pulleys I can machine them out of shaft at work but if there is a simpler faster way like casters I am all ears. Thanks Aaron
 
aarolar said:
I am fixing to commence construction of my grinder and have a few questions. On the no weld grinder plans the motor mount plate is hinged what exactly tensions the belt or do you just rely on the weight of the motor to provide tension? (step pulleys being used) Second, what is a simple cheap way to make your pulleys I can machine them out of shaft at work but if there is a simpler faster way like casters I am all ears. Thanks Aaron
Click to expand...

The motor weight acts as a tension! There is no substitute for quality pulleys! Cheap imitations will give you many problems such as vibration, noise,etc,etc.
For the time you will put into machining your own Maska pulleys will be worth the money.
http://shop.ebay.com/i.html?_kw=step&_kw=maska&_kw=pulley
These are the same pullies that they use on KMG griner I think is what Rob said!:D
 
I hesitated about responding to this thread, but I saw something that happens all too often...you seem to be going about building a grinder with the idea to do things as cheaply as possible. DON"T!

The toughest thing to make individuals understand about a knife grinder is that the more precision the machine is, the better it's going to work for you...that's the reason that the top tier, commercially available grinders cost as much as they do. You're paying for the precision. Building a grinder correctly is a lot more difficult than what most realize. In order for it to operate smoothly and efficiently, everything that turns should be precise, all the pulleys need to be precision aligned, and as balanced as possible. Otherwise all you end up with is something that looks like a grinder, that your always fighting with and fussing over.
IF you can make PRECISION parts, then do it....if you can't, buy the very best parts you can get....otherwise you're just gona be unhappy with the results.
 
Ed Caffrey said:
I hesitated about responding to this thread, but I saw something that happens all too often...you seem to be going about building a grinder with the idea to do things as cheaply as possible. DON"T!

The toughest thing to make individuals understand about a knife grinder is that the more precision the machine is, the better it's going to work for you...that's the reason that the top tier, commercially available grinders cost as much as they do. You're paying for the precision. Building a grinder correctly is a lot more difficult than what most realize. In order for it to operate smoothly and efficiently, everything that turns should be precise, all the pulleys need to be precision aligned, and as balanced as possible. Otherwise all you end up with is something that looks like a grinder, that your always fighting with and fussing over.
IF you can make PRECISION parts, then do it....if you can't, buy the very best parts you can get....otherwise you're just gona be unhappy with the results.
Click to expand...

You would be wrong with that assumption I have the ability an tools to make my own quality parts cheaply at the cost of my time. I make a living building things from steel including automated machinery.
http://www.indmachine.com/
 
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No offense was intended by my post. It's just that all too often individuals seek cost savings over quality when it comes to building their own grinders, and all too often the results are something that looks like a grinder... with lots of issues, and very limited functionality. You never mentioned your abilities, only that you were looking for "a simple cheap way to make your pulleys". That's just one of those statements that raises a red flag, which is why I responded as I did.
If you can build the parts and assemble them in a precise manner, then your a couple steps ahead of many.
 
Same on my end no disrespect meant I just wanted to clarify that fact. The drive pulleys will be purchased the pulleys the sanding belt will ride on will most likely be made from shaft of some sort.
 
aarolar,

I wish I had access to the same tools and skills to help make the parts needed for that grinder!

Take some pictures of the process if you would be so kind!

Thanks,

Doug
 
I am in now way taking the cheap road in my grinder build, my estimate of the total cost when finished w/o belts is just over $1100. Yes I am using the cheaper poly contact wheels to get me up and running, but its not so much me being cheap, its just what I can afford at the moment. I did manage to save big time on my motor, $50 for a 1.5 hp Leeson 3ph. I took it in to be serviced and I I got a call the next day saying it looked like it had never been run and didn't need service:thumbup:
 
Filling out your profile would have told us a lot that has been assumed wrongly.

What Ed and I will both tell you is to design your grinder as heavy as possible....and then go 50% heavier. The bigger the bearings , arms, and wheels the better. Precision machining to the .0001" will pay off big time. If the words, "How can I do this cheaper?" ever come out, slap yourself and swear never to say that again until the grinder build is finished.

Since you are building this from scratch, look at photos of KMG's, Bader's, and other grinders for inspiration.

Any possible vibration source should be eliminated. Mount the motor as a direct drive on a C-face, not on a hinged plate with a V-belt.

What I would suggest if you have good machining skills and a full duty shop is to make a 2X132" grinder. Use a 2-3HP 3PH motor and a VFD. You will never regret tis decision. If you decide that knifemaking is not your thing, you can sell such a unit in five minutes.
 
Keeping in mind what Stacy said just above me,

If you have skills and access to machining equipment,
have a look at the KMG Clone and the EERF below

For almost the same investment in time and materials, you will end up with a much nicer end product.

Investigate the Mapp arm and integrate a second tool bar receiver into the design for the greatest tool rest versatility.

DIY 2 x 72” Belt Grinders

KMG Clone
Free Plans
http://www.dfoggknives.com/PDF/GrinderPlans.pdf

NWG No Weld Grinder
http://www.usaknifemaker.com/plans-for-the-no-weld-grinder-sander-nearly-50-pages-p-723.html

EERF Grinder (EERF =“Free” backwards)
Free plans
http://wilmontgrinders.com/EERFGrinder.aspx
http://blindhogg.com/blueprints.html

Buy the kit
http://polarbearforge.com/grinder_kit.html


Mapp arm
http://www.bladeforums.com/forums/showthread.php?t=466024
 
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For now I am going with the KGM plans and a 1hp 110volt motor so I am going to stick with the hinged motor mount to make it easier to change speed via step pulleys. I am renting at the moment and do not have a real shop so I don't want to spend my time running a second 220 line out to the pump house I am using as a shop when I only plan on being here for another year at most. I actually have a 3hp motor that will be used when the time comes but for now I am keeping it simple and portable.

Now more questions, what size should my belt drive wheel be and do I need to crown the belt rollers or will they be ok flat?

Does anyone have any pictures of a KGM clone they have built I am curious if the flat plated attachment will tilt to a 45 ok because I prefer to grind at an angle instead of 90*
 
aarolar said:
what size should my belt drive wheel be
do I need to crown the belt rollers ?
Click to expand...

Depends on the speed of your motor

I take direct drive 3400rpm and 6 inch drive wheel as max speed compared to some factory made grinders

by using the 1700 rpm motor, the 2-3-4 inch three step pulley and a 6 inch drive wheel will give
1/4 1/2 and 1 ratios of the max speed


if you have a 3400 rpm motor
use a 3 inch drive wheel to get that reduction you didn't get with the 1700 rpm motor .

I have seen 4 degree bevels on the drive and tracking wheels

Look at the website of the origional
http://www.beaumontmetalworks.com/
he sells a 6 and 4 inch drive pulley

aarolar said:
Will the flat platen attachment tilt to a 45 angle
Click to expand...

Google Search Images
KMG grinder
KMG clone

Yes
See the hole and arc for the screws
kmg-pla0.jpg
 
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12345678910 said:
Depends on the speed of your motor

I take direct drive 3400rpm and 6 inch drive wheel as max speed compared to some factory made grinders

by using the 1700 rpm motor, the 2-3-4 inch three step pulley and a 6 inch drive wheel will give
1/4 1/2 and 1 ratios of the max speed


if you have a 3400 rpm motor
use a 3 inch drive wheel to get that reduction you didn't get with the 1700 rpm motor .

I have seen 4 degree bevels on the drive and tracking wheels

Look at the website of the origional
http://www.beaumontmetalworks.com/
he sells a 6 and 4 inch drive pulley



Google Search Images
KMG grinder
KMG clone

Yes
See the hole and arc for the screws
kmg-pla0.jpg
Click to expand...

I am using a 1700 rpm motor and have not yet chosen my step pulleys so I will get the 2 3 4 step pulleys and use a 6 inch drive pulley. The rest of the pulleys I am planning on around a 2 inch diameter.

I know I can make the platen rotate to 45 but will the geometry between the top pulley of the platen and the idler pulley be ok?
 
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