Large diameter grinding wheel build.

Lyon

Lyon

Well-Known Member
I have been wanting to get a proper grinder built and was fortunate to be able to get my hands on a couple of wheels. I am lucky to live close to Bruce Bump and he had come across some 20 inch band saw wheels that were begging for a new life :biggrin:. The wheels were 20X1.4 ish. Bruce was wanting them for a 1 inch belt so he traded me a couple of wheels for milling down a couple for him.


Next step is to get them shipped out to http://www.sunray-inc.com/ and have some rubber put on.

There isn't a whole lot in info on making large diameter grinding wheels so I figured I would get it posted up. The rubber work was quoted out at 100$ per wheel which doesn't seem bad at all when a 14 inch new wheel will run an easy 400$. The biggest draw back is getting any machine work done which I am fortunate to be able to do myself. I think this is the first time that the compound rotary table has actually saved me money :D. (I am a hobbyist not a machinist.)
 

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I hope this works. It would seem like a cheaper way for a large diameter wheel...
 
Hey Matt,
Thanks for posting up the wheel project.
I came across 4 of these, they are industrial size 20" and high quality. I've been thinking about making more slip joints and think the narrower 1" wheel should give me a precise crisp grind on the small blades. I like the looks of the slight hollow grind a big wheel gives. I'm also thinking a smaller horse power DC motor with a variable speed control is all thats needed for the light weight application here.
 
This is a "neat" project. I would love to have a large 1" wide wheel to work with. The 1" wheel allows for easy grinding of inside curved blades and that 20" wheel will certainly give that "reserved" hollow grind I like so much.
Frank
 
Bruce Bump said:
SunRay will recover these wheels. They are the most resonable priced and seem to be highly recommended. Ed Caffrey uses SunRay wheels, so I,m thinking we should too. Here's their web link: http://www.sunray-inc.com
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Hello Bruce
Are you planning on making all 1" or can a 2" wide be made. If there is a 2" x 20" available I would be interested? What's the Arbor size?
 
Frank Niro said:
This is a "neat" project. I would love to have a large 1" wide wheel to work with. The 1" wheel allows for easy grinding of inside curved blades and that 20" wheel will certainly give that "reserved" hollow grind I like so much.
Frank
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That what I've been told too. The narrow wheel does good re-curves much smoother. Are you in the market for one possibly? I just may have a spare.
 
rhinoknives said:
Hello Bruce
Are you planning on making all 1" or can a 2" wide be made. If there is a 2" x 20" available I would be interested? What's the Arbor size?
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Laurence,
I am making 2 wheels both are 1"
Matt is making 2 one inch wheels also but they will be attached with alignment pins so he can use both together for 2" or remove one for a 1" wheel. That should be very cool if they are CNC matched for diameter and I assume they are.
I put in a request for bid on a solid polyurethane 1" x 20" wheel with a ball bearing center for a 1" shaft. I'll let you know what they say. It may be a good deal to just have them make you a 2" wheel.
 
Bruce Bump said:
Laurence,
I am making 2 wheels both are 1"
Matt is making 2 one inch wheels also but they will be attached with alignment pins so he can use both together for 2" or remove one for a 1" wheel. That should be very cool if they are CNC matched for diameter and I assume they are.
I put in a request for bid on a solid polyurethane 1" x 20" wheel with a ball bearing center for a 1" shaft. I'll let you know what they say. It may be a good deal to just have them make you a 2" wheel.
Click to expand...

I think My Hardcore grinder has a 5/8" Arbor? I will measure it in the morning. Would a 5/8" be to small to run a wheel that large safely? Anyone know?

I will have to start keep an eye open for old wreaked Bandsaws with large wheels.
 
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Something to consider when going big is that the circumference of a 20 inch diameter wheel is 62 inches. I put the 72 inch belt around it for fun and there is no way to run them. The next size up with any kind of selection is 2X132. You can still get up to an A6 grit but you don't have near the selection of the 2X72 belts.

I mention the circumference in reference to the 5/8 arbor. I would guess that a grinder redesign would probably have to happen so may as well go with a bigger shaft.

Also, band saw wheels just happened to be what was at hand. Bruce has a 24 inch track wheel what came off of a tank :biggrin::52::biggrin:

It will be interesting to hear what the cost of just having a wheel made up will be. For 2100 SFM the wheel will be turning around 400 RPM. I wonder what an engineer would say about standing in front of one of these.

http://www.calctool.org/CALC/phys/newtonian/centrifugal
So, 5 oz on a 20 inch wheel at 400 RPM takes 14 lbf (pounds of force) to hold it in place. The wheels were about 8lbs each and much heavier in the middle. 400 RPM, 1.5 pounds = 68 LBF. 600 RPM, 1.5 pounds = 154 lbf. I just learned a bunch of new stuff today! One of them is NOT the max speed at which I would want to stand in front of a large diameter home made wheel with a would be knife in my hand. :les:
 
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I got the quote back from SunRay on a new wheel 1" x 20" with a bearing installed for $513.77
Its actually not a bad deal as it something only a specialized shop like theirs can accomplish.

I think safety is a real concern if makers are using a wheel that could fly apart. A new wheel from SunRay would be the best case for most quality grinder building projects. Both speed reduction pulleys and variable speed working together are a must to keep the RPM down and surface feet per minute reasonably slow. The motor doesn't need to be powerful if gear reduction is used. Its like putting your truck in low gear to climb a hill, there is plenty of power in low gears. My big 2x132 grinder with the 24" wheel, 14" idler wheel and 8" tracking wheel is only running a 1 horse power motor.
 
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Bruce,

Do you happen to know what kind of band saw they came off of? It would be nice to know the SFM that the wheels were running at.
 
Lyon said:
Bruce,

Do you happen to know what kind of band saw they came off of? It would be nice to know the SFM that the wheels were running at.
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I don't know the brand name, just that they came from a huge bandsaw used at Martins Archery Company here in town. I,m not sure if it was a 4 wheel machine or 2) 2 wheel bandsaws. With proper rubber I wouldn't be concerned about SFM.
 
And they are done!

All in all things worked out pretty good. The price was $95 per wheel. The spec's were 1 inch wide and 21 inches in diameter so all things considered finding a good used wheel and having it coated is a big money saver. The cost for a new wheel of that size is $500. The main thing when going used is to make sure that the wheel is actually made to spin that fast. You won't need to spin it faster that 800 RMP which will put you in the 4200 SFM range but at that speed a balanced wheel will start to matter.

The minimum rubber thickness they can do is .5 inch which should be about perfect. I never asked what the full range of rubber hardness that they have but I do know they have from 70 - 90 so it fits what the knife making community uses. They can also do serrated as well. I had a couple of smaller wheels made up for a conversion I am doing to a universal tool grinder and the prices were pretty good. I believe the 8 inch wheel with a serrated surface was around $135.

IMG_20150319_093748_135.jpgIMG_20150319_093758_200.jpg
 
I just got a 4.5" and a 10" from SunRay. Both look good so far, only used the 10" for a few minutes, but no issues yet.

Ordered the 10" w/ 3/4" id bearings, and turned an axle for a tooling arm to match. Price was the same, and figured it might make the setup slightly stiffer for profiling or hogging.

SunRay was verynice to work with.
 
Thanks for sharing the build on these wheels guys. I may go hollow someday when I start making more field/hunters? For culinary flat's and convex work so well I have no complaints.
 
rhinoknives said:
I think My Hardcore grinder has a 5/8" Arbor? I will measure it in the morning. Would a 5/8" be to small to run a wheel that large safely? Anyone know?

I will have to start keep an eye open for old wreaked Bandsaws with large wheels.
Click to expand...
Laurance, I,m sure your 5/8" shaft will run the big wheel, at least one like this one as its really light weight. Variable speed is a must though to keep surface feet per minute down to a safe speed.
 
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Not sure how you would make this work on a Hardcore, Laurence.

It's a 2 wheel grinder, with no tool arm, so the drive wheel, and the idler have to be sized appropriately to give you the proper circumference.
You can't even switch between an 8", 10", or 12" wheel without also changing the idler.
 
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