Surface grinder Belt conversion help

Huntsman Knife Co. LLC.

Huntsman Knife Co. LLC.

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I picked up an old 612 Harig a few months ago and have decided to convert it to run on 2x72 belts for more rapid material removal+ tapering tangs on tomahawks. Im ordering a new 1.5-2hp motor (hopefully this wont be overkill and throw blades at the wall, but 1HP just seems insufficient with a 2in contact surface) and VFD for it and have a spare tracking and idler wheel for the conversion. Only problem is I can't figure out how I'm going to attach the contact wheel. I plan on custom ordering one from sunray or contact rubber in 100 duro with serrations.

What is the best way to attach a 2x7 wheel to this grinder? I've included some pictures. I would really appreciate some input on this as I'm completely stumped.

surfacegrinder1_zpsc771f9bf.jpg


surfacegrinder3_zpsfca04a3b.jpg


surfacegrinder2_zps5d433ba0.jpg
 
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There are some other forums that might be helpful.

Practicalmachinist.com
Bbs.Homeshopmachinist.net
Hobby-machinist.com

There s likely a fairly simple solution although without proper equipment, it might be a bit costly. Good luck.
 
all you have to do is order your contact wheel with a 1 1/4 hole in it. or better yet a 1 inch hole that you can have machined/bored so that it will just slide over your hub adapter. machining the hole helps ceter the contact wheel on the hub so there is less material to remove to true the wheel and lessens the chance of vibration.
 
When I sent my wheel dimensions/specs to Sunray, it came back so close that about all I had to do was hand lap the bore hole a bit with some sand paper and tap it on.
Just give them the dimensions and let them do the thinking.
Give 'em a call.
 
This is the quote I got from www.contactrubber.com
I was referred and will most likely do business with them when/if I go ahead with the belt mod.

6" Diameter x 1" Wide x 1.250" Bore
90 durometer rubber
Standard Serration
Balanced
PRICE: $173.75 net
DEL.: ships in approx. 3 weeks
 
Some other things,

It is not recommended to change out the motor because of balancing issues. I guess three phase motors on surface grinders are kind of a task specific motor and issues may arise if you just slap something else on.

Also with a two inch belt you don't need to have a two inch surface in contact with the blade. You move the belt across the surface at any rate you choose, so it could just be a few thousands if you choose. Only the leading edge of the belt is in contact with the metal.

Good luck on the conversion, I have a surface grinder that I have considered converting but would rather just buy a conversion, but I don't think anyone offers one.

Thanks

John
 
Thanks so much for the replies.

So for the contact wheel should I attach it to the tapered arbor or to the threaded attachment that goes over it? I'm guessing the attachment since that's where the stone wheel sits.

JMJones- I'm concerned about the balancing of the motor. When I took the motor off, the connector that joins the motor arbor to the arbor inside the spindle had lots of holes in it indicating it had been balanced. I'm in a bit of a dilemma though. I'm fairly certain that the motor on my machine is original (probably 30 years old). Its a 1hp motor and it doesn't produce much torque. I've actually stalled it out when making a deep pass (.008) with the stone. It also runs extremely hot so that's probably not good.

Is there any chance that the new motor will run OK without balancing? I just don't think the original motor is going to cut it running belts which will cause even more resistance.
 
I built 2 conversions this week!
Sub-1 HP on a 612 is what I have been running for several years, works fine.
Belts cut much more freely than a stone, never even approached stalling it.

Why did you take the spindle out!
That's bad JuJu...

Just make sure you calculate your offset in your wheel to maximize your use of the table.
$175 - $200 is the going rate for these wheels from Contact rubber, ordered 2 on Monday.
 
Fellhoelter thanks! Is there any way you could post a picture of what your contact wheel setup looks like? How did you attach it to the 612 and what were the specs on the wheel you ordered for it?
 
I am not allowed to post pictures!
Sorry, I can't help!
I want to... But, that's why I am not here so much anymore.
It's too difficult to help people.

.750 seems to be the right offset on a Harig 618 that I have now, though I don't have the wheel yet. That's for a 2" wheel BTW.
The wheel just mounts on a Sopko adapter, then on to the taper.
Your second picture shows your spindle with an adapter half mounted to it...
 
FWIW, from Contact Rubber

N130
6" Diameter x 2.250" Face x 1.250" Bore
80-90 Durometer Rubber
Standard Serration
Balanced
PRICE: $209.75 net

I am going to a wider face on this wheel so that I can dress a fully supported Gator belt with a diamond.

90% of the time I am actually running 1" belts, but want to be able to do 2" belts.
 
You're expecting too much out of your surface grinder.
These are NOT!! for heavy stock removal.
.008"??
I have never even come close to trying to remove that much material with my belt conversion.
I only remove approximately .002" per pass. And that's with a sharp 36 grit.
When I go to finer grits like a 120 or a Gator 100 or 45, I only remove .001" at a time.
And you work your way across the work piece a little bit of the belt at a time.
Now, you can use a two inch wheel and only a 1" inch belt, since you are basically cutting with the leading edge of the belt anyway.
Unless that motor is shot - you don't need a new motor.

KalEl said:
Its a 1hp motor and it doesn't produce much torque. I've actually stalled it out when making a deep pass (.008) with the stone. It also runs extremely hot so that's probably not good.
I just don't think the original motor is going to cut it running belts which will cause even more resistance.
Click to expand...
 
I could take/post a picture of Fellhoelter's old one but he still has the part I need to make it work.
 
I'm trying to make this one work like Mick Strider's grinder. He uses 2x72 belts and can remove some serious material with each pass. I want to be able to quickly and accurately taper tangs on my 3/8th thick hawks and put distal tapers on my bigger blades. And also, just a thought, but maybe it would be possible to grind bevels on tall blades like kitchen knives using precision shims?

[video=youtube;pP-68vC1_OY]http://www.youtube.com/watch?v=pP-68vC1_OY[/video]
 
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Fellhoelter said:
I am not allowed to post pictures!
Sorry, I can't help!
I want to... But, that's why I am not here so much anymore.
It's too difficult to help people.

.750 seems to be the right offset on a Harig 618 that I have now, though I don't have the wheel yet. That's for a 2" wheel BTW.
The wheel just mounts on a Sopko adapter, then on to the taper.
Your second picture shows your spindle with an adapter half mounted to it...
Click to expand...

That's been clarified and rescinded, post away.
 
12345678910 said:
That's been clarified and rescinded, post away.
Click to expand...
But I genuinely do not even have the ability, the option is not there like it is on every other forum!

Yes, I have been told I am allowed to post helpful pics, but the button for doing so in the reply box does not allow it!

It's like telling your kid he's welcome to drive the car, when there is no motor under the hood...
 
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Don Hanson III said:
I sure wouldn't want a 2" wheel, or 2" belts on a surface grinder. 1" is plenty .
Click to expand...
2" are really convenient sometimes.

You can remove a TON of material fast when you have a coarse belt on and plunge cut.

Then come back with a finer belt, and a more traditional technique to get parallelism and surface finish.

I can easily take .020" or more off of a couple of folder blades in one minute or less, and with much less physical labor.

You can also dress fine Gator type belts with a diamond, and then plunge full width and get pretty damned parallel, and a little different finish.
 
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