stirrin' the pot ...thinking of a new grinder....

Razorhunter,

Contact wheels are the most efficient way to grind. Since the wheel turns with the belt...rather than pinching the belt between the work and a fixed plate like the platen. The softer rubber face on the contact wheel provides a better surface finish...and the cushions the thump from the thicker belt seam. You can get exceptional finishes with a contact wheel by using belts grit as fine as you wish. On a hard platen attachment, however, there is no use going past 220grit or so because the thumping from the belt seam does more damage than good.....and the problem is aggrevated with finer grits. Also, you get better belt life with a contact wheel. The platen, being hard tends to crush and strip the abrasive from your belts. Guys that are advocates of flat ground blades have to live with the problems associated with platen grinding......unless you use a contact wheel that is sooo big, it provides a blade grind that approaches flat. In short, a contact wheel can save time and money. Saves time by providing better finishes off of the machine. It saves money by extending the life of your perishables. Flat ground blades simply require more work by hand. I think this is why in the production knife industry....the majority of production is hollow ground.

Sincerely,
Rob
 
jhiggins said:
Not to poopoo on Doc's idea for the spoked wheel, but spokes would also provide a place for fingers and whatnot to get caught in. I would recommend a solid-disc center, just thin to save on weight. Spokes would be pretty, but not safe when a large mass is rotating under torque. Loss of fingers could happen.

I also like Mark's idea about swiveling the drive motor with a pivot point and a fine-adjust screw of some kind. A threaded screw rod, and a small hand-wheel would be excellent to achieve this.

Another design idea would be to connect a right-angled gearmotor directly to the contact wheel, and then you could have a bar, adjustable idler, and spring arrangment just like the KMG, except in reverse!
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Oh come on Jeff! What are a few fingers amongst friends? You could afford to lose one or two. You have ten of them....

I had not thought about the openings being a problem, but that could be sloved with something a little stronger than the ultra thin center section by using spokes, and sheet aluminum hub covers that screw to the center and the outside hubs.....like the old style Moon discs. The spokes would offer more strength against flex than a thin center, and the covers keep your fingers out of them. May be more pieces than it is worth, but it is something.

Mark wants a surface grinder Ron! I think he has been hinting at it a little here and there. You think you could rig him up a surface grinder? He is really buggin for one.

Doc
 
Ok, so my idea must not be possible. So how about a treadle operated one? That big of wheel it would be easy to get moving wouldn't it? That would be old school!!! :D How much hp where the motors on the grinders that they used to grind the original bowies? :rolleyes:
 
I used to sharpen axes and other tools on a treadle-style 3" width stone wet wheel as a young kid at my Grandpa's sharpening shop. I wish I had that old relic today. It was probably 30" in diameter, though it's hard to recollect.

Actually, Trick, a lot of the Sheffield Bowies were ground in factories where there were banks of powered 6 foot stone wheels with boards hunkering up to them the grinders lay down on. Too large for foot power, I would assume they were water-powered early on then gradually moved to steam. I wish I could find the foto I saw of that, it was pretty cool.

For any not familiar with it, Dana Acker has a foot-powered sit-down stone grinder made from a bicycle. There was a foto on Knife Network awhile back. It wouldn't be a real stretch to convert that to a contact wheel and belts if one so chose.

Personally, as a broke down old fart, I'll take the motorized version! ;)
 
fitzo said:
I used to sharpen axes and other tools on a treadle-style 3" width stone wet wheel as a young kid at my Grandpa's sharpening shop. I wish I had that old relic today. It was probably 30" in diameter, though it's hard to recollect.

Actually, Trick, a lot of the Sheffield Bowies were ground in factories where there were banks of powered 6 foot stone wheels with boards hunkering up to them the grinders lay down on. Too large for foot power, I would assume they were water-powered early on then gradually moved to steam. I wish I could find the foto I saw of that, it was pretty cool.

For any not familiar with it, Dana Acker has a foot-powered sit-down stone grinder made from a bicycle. There was a foto on Knife Network awhile back. It wouldn't be a real stretch to convert that to a contact wheel and belts if one so chose.

Personally, as a broke down old fart, I'll take the motorized version! ;)
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Now Fitzo,

I have learned volumes from, in your own words,"Broken down old farts". Don't be too hard on yourself there man. I doubt age has taken much away from you except the urge to hurry up and get done.

I am going to have to talk with Ron aboutmy plan for knifemaking domination. We should come up with a machine that will capture and freeze the "Broken down old fart" knifemakers, and allow us to preserve them until we need information about how to do something.BWAAHAHAHAHAHAHA!

Ya'll have a good weekend.

Doc
 
Thanks, Doc! Actually, I lied: I'm not really "old" (53). :)

You have yerself a good weekend, too!
 
This avatar you have posted makes me think you are a bear of a fella.

53 is far from old. I am 36 (I know I know), and work with my 82 yr old grandfather every chance I get. He is many things....wise, stout, old, and ornery and he still runs circles around me, my uncles, and a couple of my cousins. I am trying to find a way to freeze his butt too. I would hate to lose out on the knowledge that I will be missing when he is gone.

Trying to get my 14 yr old to start getting some lessons of some kind off of him. The old man has forgotten more about many subjects than I will ever know.

Doc
 
Doc Hollywood said:
This avatar you have posted makes me think you are a bear of a fella.
Doc
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Well, thank you, sir! Actually, I look more like a beached whale nowadays at 6'3" and 300 pounds! What once was in weightlifter shape at 215lbs is now a large pale mass of quivering jelly! :eek:
 
Rob-

While it's a very cool idea and obviously getting a lot of good feed-back...

I think it would be like when I bring a fancy dagger to a show. A couple hundred people will pick it up and say it's great, this and that...but then NONE of them pony up the $$$ to actually take it home.

I don't know if you'd have a large enough market for this type of unit to tool up for it. I doubt many people realize how much is involved for you to get set up to do something repeatably.

I am NOT trying to be negative here, just looking at all sides of it.

If anyone could pull it off....it would be YOU!!! :D

-Nick-

http://www.wheelerknives.com
 
fitzo said:
For any not familiar with it, Dana Acker has a foot-powered sit-down stone grinder made from a bicycle. There was a foto on Knife Network awhile back. It wouldn't be a real stretch to convert that to a contact wheel and belts if one so chose.
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Ha! Assuming one was coordinated enough to grind and pedal at the same time! Which I ain't. I'll stick with the motorized version too, thank you very much.

So here we are with a Nick Wheeler who's so good looking women swoon, makes world-class knives anyone with half a brain would die for, and now he's waxing pragmatic too? Gimme a break!

Nick, you suck.

In a nice way of course. ;)

But frankly I'm betting Rob won't take this too far without having done his marketing research. While a curved platen might do the trick for occasional use, anyone who really wants to grind shallowly (is that a word?) often will surely find a way to cover one. I'm guessing this thing could usher in a whole wave of knife design. Or more accurately, take us back to our roots. And you Nick, will just have to get one too. :D
 
Yea yea, nanny nanny poo poo.... :p



Guys, don't get me wrong...I would love to see something like this, AND actually own one. For grinding a Sheffield bowie a 36" wheel would be the cat's meow! But "want" and "can have" are usually two different animals.

And NO, I'm not so arrogant as to think that just because I can't afford one right now, means nobody else can either! :p

Was just giving a different $0.02

As to the surface grinder thing... I bet Rob could build one. But the cost would be way up there for the work involved.

-Nick-
 
Matt Shade said:
Yeah Dan, don't argue, I was agreeing with you :D
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no arguing :grumpy: man you're taking the fun out of this.. :D

I'm going to put a belt on the back of a logging skider, jack the tire up put her in gear and start grinding :rolleyes: :D
 

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Looks to be about a 1 grit right now. Pretty good for hogging if you can hang on.... ;) VS, too!
 
Yeah, Variable Speed. I figured if you could hog with that you could work the gas pedal with one foot, too! :footinmou

Don't mind me, Dan! I'm just carrying on. And, no, I ain't been ingesting anything! ;)
 
Ron

What you said about the platen damaging the abrasive grit on the belt is a good reason to try to develop the rotary platen idea to simulate a large radius contact wheel or platen. Perhaps one could use a series of small diameter wheels with a thick rubber belt. The centers of the wheels would be arranged along an arc.


With all you guys suggesting the "sculpted" spokes for the large contact wheel, I was wondering when someone would mention adding a "spinner" like what you see on the SUV's that rappers pose in. That might open up a new market for some makers who would be willing to deal with such customers :D Just post a picture of it on your website in the shop tour section.

I get wierd ideas when I stay up late. I'll shut up now. :rolleyes:
 
Rob,
Why not turn your machine around and run a big wheel right on the drive shaft, move the tracking wheel higher and further back (use a longer arm and taller riser) to get it out of the way and run an idler wheel on a tooling arm out of what would now be the rear of the grinder? You would of course have to position the machine to the right of the base so the 36" wheel has clearance. This way your machine could use all of the same parts you now have on hand you would just need to relocate a few holes. Just a thought.
I have two of your grinders now and have been itchin' for a third if I can find room. Oh yeah, 36" wheel please.

Mike D
 
I rigged up a KMG mounted surface grinder attachment a couple of years ago. Then sent the pic to Rob. The preliminary conclusion was that there were lots of problems to be worked out if it were to be a viable product. Some precision might have to be sacrificed to achieve a basic surface ground finish.

Here's what I did though.....I picked up a heavy duty drawer slide from the hardware store and used a chunk of aluminum channel stock as my carriage. The drawer slides go on either side of the channel. Then I rigged up a series of aluminum brackets so that the thing mounts on the arm and sits in front of the grinder in a vertical position. To use, I double sticky taped the piece to the channel and then pull the "carriage" up and down against the contact wheel. It actually worked pretty well, sort of. :D The biggest problem was that there is no fine adjustment in and out and no way to square it accurately against the wheel. Problems that are surmountable I am sure for a more accomplished machinist.
 
Dan Gray said:
no arguing :grumpy: man you're taking the fun out of this.. :D

I'm going to put a belt on the back of a logging skider, jack the tire up put her in gear and start grinding :rolleyes: :D
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Cool :cool:

I was just wondering about lettin some air out of the back tire on my pickem up truck, wrapping a belt around it and then bumping it back up to 80 psi (I've got a couple heavy duty jackstands to put under there). Anybody know where I can get 8"X98" belts?:D Only trouble is I aint got cruise control :grumpy:
 
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