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+--- Thread: Old sharpening methods... (/showthread.php?tid=280)
RE: Old sharpening methods... - EOU - 04-05-2018
That's the ticket Thomas! What do you suppose the abrasive nature of the wheel is on these machines with regard to grit, and type of abrasive or is it just some sort of natural stone?
RE: Old sharpening methods... - Edgepal - 04-05-2018
They have, I think, both natural sandstone and a "alu stone" inntheir sortiment. I do not know what a alu-stone is - but perhaps you know. I know that it is a fine stone...but not how fine... Sorry.
What I know is that Kirunaslipen have a very good reputation and they produce everything with high quality.
Thomas
RE: Old sharpening methods... - Mike Brubacher - 04-05-2018
Yes, don't know either about "Alu Stone" Thomas. Found Alum Stone but that sounds unlikely since its used primarily in cosmetics. Maybe they are making stones with Alumina Oxide abrasive in it and calling it Alu Stone.
RE: Old sharpening methods... - Ken S - 04-05-2018
My guess would be aluminum oxide, the standard manmade grinding stone compound.
Tormek originally used natural grinding wheels mined on an island off the coast of Sweden. As I recall, it was Gotland Island.
The aluminum oxise wheels are coarser.
Ken
RE: Old sharpening methods... - Edgepal - 04-05-2018
We havs two places where they produce sandstone sharpeners, as you wrote,mghe Island of Gotland on the south Swedish East coast and then in Orsa in parish Dalarna. In Orsa they still make grinding wheels up to 65 cm diameter - but they only produce bench sharpeners on Gotland. Gotland have produce grinding wheels during loooong time before.
Thomas
RE: Old sharpening methods... - Ken S - 04-05-2018
Mike,
If you are planning to design and build a pedal powered wet grinder, your knowledge of "modern grinders” (high speed dry grinders) can be as much of a hinderance as a help. Most wet grinders (essentially Tormek clones) are designed with high speed dry grinding thinking. The most obvious giveaway is the shaft. Most are not made of stainless steel. Tormek switched to stainless in 2006. If you are going to go through the trouble of building a solid machine, why not have it last?
Tormek has the TT-50 truing tool. When you are still in the designing stage, incorporate a good dressing and truing tool into your design. Your grinder will be a pleasure tool; make it easy to keep running true and cutting well.
Tormek uses nylon bushings instead of sealed bearings. Running at 100 RPM, it is not a high speed, high heat machine. The nylon bushings work fine and last for many years.
Consider something like Tormek's universal support bar.
In my not terribly scientific mind, the large grinding wheel serves as a flywheel, helping to keep itself spinning. When I worked off the Maine coast almost fifty years ago, I remember a "one lunger", a working boat with a one cylinder engine. Getting into reverse meant stopping the engine and hand turning the flywheel in the opposite direction. Simple, but effective. That simple bidirectional festure would be nice to have. Some of us prefer to sharpen knives and other tools with the edge trailing.
Just a thought, if you make your bushings U shaped, open at the top, cleaning and regreasing would be a snap. A stone that size won't escape. Changing grits would be simple, too.
Do keep us posted.
Ken
RE: Old sharpening methods... - Mike Brubacher - 04-06-2018
Those are all very good suggestions Ken. I see no reason why the "Tommy Wheel" aka "Thomas Project" should not build upon the lessons learned by Tormek. I think that the ability to reverse direction is "baked into the cake" if we use traditional drive methodologies and not a lot different than the reversing scheme you describe in the one lunger engine with flywheel. I hope that our Thomas is not offended by the more familiar term used here for his name. If you are offended Thomas, just let me know. In my first job out of college (with Georgia Pacific) my sales manager's name was Gordon. All of our customers referred to him as "Gordo". I asked him if that bothered him. He told me that "I don't care what they call me just as long as they call me". While I'm on a roll here with names and the Georgia Pacific company, here's another one. We had a female accounts receivable clerk at our branch who went to an out-of-town bank and opened a checking account in the name of "Miss Georgia Pacific". Two weeks and 1.4 million later corporate figured out that something was wrong. By that time, she was gone and so was the money. That scheme probably wouldn't work today. Today, I have to swipe a bank card and show two forms of ID just to make a deposit in our corporate account. But I digress so back to business here.
Ken and I discussed via email this morning provision for deburring with the Tommy Wheel. I told him I had an idea and that I would send pictures. I decided that we just as well share with everyone. We have been experimenting with more efficient deburring methods and here is one that seems to work quite well. I think that this design could be incorporated into a sort of "flip out of the way", friction drive, device for the Tommy Wheel. We currently drive this prototype with either a fixed RPM gear motor or with just a drill motor if we want to test at different speeds.
[attachment=598]
The "belt" is simply a high durometer .125" diameter "O" ring and is shaft driven from the backside. The pulleys are slightly offset so that the belt clears itself at the "V". We know that rubber works well for deburring from our Sharp Pad experience. In this design, up to three belts can be used at the same time.
[attachment=599] [attachment=600]
The concept is simple; pull the knife through and the burr is first pushed one direction and then back. Of course we get away from the flipping the knife over process that is so time consuming. If three belts are used this process is repeated three times with one knife motion. Using one belt, usually four or five pulls removes the burr. Does the edge cut the belt? No. The belt is always moving away from, not into, the edge. It will not remove those short, super gnarly burrs that have have been created by using too much grinding pressure. The burr in that case acts like a scraper and just starts to remove rubber from the belt. Any reasonable burr created by the sharpening process comes right off. Its an absolute dream for those super malleable burrs that Grepper has complained about.
The project pictured here can barely be called a prototype. It is more "proof of concept" in this state. As mentioned earlier, a friction driven version for the Tommy Wheel might just be the cat's meow.
RE: Old sharpening methods... - Edgepal - 04-06-2018
Mike, I am 192 cm long sins I was 14 years old. I have had all nick names your fantasy can think of about my length
, i did not care when I was 14 - and I do not care today. Tommy wheel are perfectly ok for me. I am happy that what I wrote started your Tommy Project and that old thoughts and things develops
Thomas
RE: Old sharpening methods... - Ken S - 04-06-2018
Thomas,
A bit of background information on "Tommy". While using a large grinding wheel is historically correct and very impressive, having a second grinder with a smaller wheel seemed intriguing. If the smaller grinder was very portable, it would be an interesting and functional conversation piece at things like family gatherings. The 250mm (10”) diameter Tormek SuperGrind wheel seems like an excellent candidate. Using the affectionate nickname Tommy for it seems a good fit. As it is named in your honor, using the Swedish word seemed a very good fit. Doing an online search for Tommy in Swedish profuced "Engelsk Soldat" (the traditional nickname for an English soldier, not our intention........)
So, we have stayed with Tommy.
Mike,
Your burr removal device is intriguing. (I would expect no less from you.
Ken
RE: Old sharpening methods... - Edgepal - 04-06-2018
I have thought about bying a Tormek T2 with diamond grinding wheels...
usefull for big grinding jobs - and no water involved...But I am instead now working with a mini beltgrinder that can be used with my sharpening tool Chef. I think it can be a nice attatchment. It can grind in wanted degrees and use chefs guide rods for both flat and convex edges.
My thougt is that my beltgrinder can remove a lot of material fast - and then work with normal sharpeners for the last precision and after that maintanence.
A thought...
Google have a 3D program named Sketchup that you can download and use for free. It is simple to learn and simple to use - but also very powerful. It works nice.
Have any of you guys use Sketchup?
With the help of Sketchup can we, if you like, construct the optimal grindingwheel together with all its parts, everything in correct size. When we are ready it can be produced from the drawings becouse all meassure will be there.
When I build my workshop, carport and firewood place it become a "barn" 12x6 meters. I build it first in Sketchup plank by plank in all details. I built it exact in all meassures - and I could then very easy calculate all wood material I need to by. When my "barn" was built - there was very little material spill.
Sketchup are a very usedul program
Thomas