Thread: How I Flatten Chisels... What's the Catch?

Maybe the next level of acuracy could be a sink coutout of a granite kitchen benchtop. They are easy to get and could be epoxied to a large pulley or whatever. Cutting it into a round shape is easier than you think with an angle grinder and cutting disk and them griding the edge on the bench grinder to a marked circle....

Originally Posted by Chris Parks

So the tolerance you refer to is the scratch pattern not the edge to edge flatness? I have never heard of a ground surface referred to that way and I can't see how an MDF platter will affect the ground surface pattern, only the grit level of the platter can do that. If we were talking of edge to edge flatness and it is asserted that MDF will not deliver an accurate result the question remains, what is the tolerance needed edge to edge as making the statement implies that the tolerance is known. I am sorry but your answer to my post makes me more confused on tolerances, accuracy and what those are exactly.

tolerance ? as in edge to edge across the back of a chisel or plane blade? you own a worksharp machine as i under it (above), so it would seem to me you have a grasp of it already. i thought that edge to edge 'tolerance' was obvious to anyone so i thought or misread you to be talking about flatness in terms of bumps and groves e.g scratch patterns.

so as far as i can see your main point of argument is that you are saying MDF is good and want me to prove why it isn't. again i think its pretty obvious the pitfalls of MDF. once any swelling occurs, of course, usually near the edges first, the disk is no longer flat. obviously you can not lay the back -or the front bevel on and expect a flat or straight edge to form. at minimum some dubbing and at worse it gets the more out in all tolerances/angles and cutting edges are effected. like i said short term should be fine, using dry, no lubricant. the back of plane blade should be flat as can be i'm not going to give you a measurement, when you put a straight edge on you can see and you can see when the cap iron is also honed how neat (perfect) the fit is. if you simply want someone to agree that MDF is fine then i am sure there are bunches of people that would agree with you. even though you bought a worksharp machine . i am not saying one has to spend a fortune or even heaps of money to get correct results. i am all for people working out cheaper alternatives. i just don't agree with mdf as a long term solution

Originally Posted by jhovel

Maybe the next level of acuracy could be a sink coutout of a granite kitchen benchtop. They are easy to get and could be epoxied to a large pulley or whatever. Cutting it into a round shape is easier than you think with an angle grinder and cutting disk and them griding the edge on the bench grinder to a marked circle....

sounds like a good idea, an thinking outside the box. as you say cutting and drilling it isn't that difficult. offcuts such as those should be easy to source. the caveats to look for might be the weight, if 30mm or more thick of natural stone or man made it will be rather heavy so the bearing set up (which ever you use or make) must be strong enough to handle it. natural stone in particular is often ground quite flat on the top side, however the underside not so much, i've installed many a bench top and often need small wedges to make the joins fit perfectly on the top side, you don't see the under-side so in kitchen applications so the underside doesn't matter. however using it as a base disk you would need to look out for this and make the ness adjustments so it turned around flat not like a warped record for example. composite man made stone is often not as thick 19mm or so (some is thicker of course) and the underside is usually flatter, also lighter but the bearing and same would still need to be checked when making but might be easier or need no adjustment on the under-side. otherwise sounds quite feasible to me


cheers
chippy

I have no argument just questions and a suggestion which I put forward and was only picking up on your assertions of accuracy or lack of it. The diamond platter is a very rigid plate and not something that will be affected by what it sits on to a large extent. Before I bought some I wondered how flexible it would be and was pleasantly surprised to find it is a very rigid thing and the substrate it sits on is not a huge factor if reasonably flat. Pittwater Pete might add some comments on the diamond plates as he has all my stuff at the moment. As a cheaper way to experiment MDF will do just fine and if treated correctly would last a fair while even with lubricants. For permanent use I would go to a plastic platter or similar material such as aluminium.

Originally Posted by Chris Parks

I have no argument just questions and a suggestion which I put forward and was only picking up on your assertions of accuracy or lack of it. The diamond platter is a very rigid plate and not something that will be affected by what it sits on to a large extent. Before I bought some I wondered how flexible it would be and was pleasantly surprised to find it is a very rigid thing and the substrate it sits on is not a huge factor if reasonably flat. Pittwater Pete might add some comments on the diamond plates as he has all my stuff at the moment. As a cheaper way to experiment MDF will do just fine and if treated correctly would last a fair while even with lubricants. For permanent use I would go to a plastic platter or similar material such as aluminium.

ok, i see somewhat clearer what you are saying. first point is i don't have the diamond disk you linked to, but it appears cheap (cheap enough to try without hurting if it doesn't meet expectations). other diamond disks i have found are used by jewellers to hone the facets on Gem stones, they come in various grits but are pricy. the disk you linked to was 100g which doesn't tell me much because as i said one persons 100g is different to another claim of 100g (perhaps they sell other grits as well?). so that may be fine to begin with with but i suspect will not be enough to finish the job (of going down to a nice scratch pattern), going down the grit or micron sizes to finish the job.

and sure you can seal MDF and then paint it further to help seal it further. of course this then adds to overall cost, one might just as easy get aluminium or some else for the same cost by the time they are finished. and in my experience it only slows down the swelling (particularly at the edges). for example i've made many kitchens, often with nice timber doors, often with vinyl wrapped draws and doors from the factory, and plenty of MDF draws and doors as a cost saving factor for the customer (their choice). obviously sealed and painted, sometimes in two pack paint. but i have found they still swell at the edges and that is in areas of the kitchen that don't particularly get much moisture, under the sink area its can happen more quickly. it does last somewhat, and the owner gets a certain amount of value for money, especially if they spec building or flipping a home. or for the time being use the cheaper method with a view to upgrade the faces later. as a result i can not honestly recommend it as a workshop material (for a long term solution) or i would feel i am doing people an injustice or misleading them to think it is suitable material to use


cheers
chippy

There is already a high torque, precision machine available with removable / interchangeable disks. The Lap-Sharp from Wood Artistry. However its in the same ball-park cost as a Tormek (but can be used for flattening backs as well as grinding & honing flat blades such as chisels, planes, scrapers, spokeshaves etc)
See this link

I have used one & it does a stellar job. There is a foot switch so you can place the blade then start rotation (and it has forward & reverse switch). Its really the "gramophone on steroids" that's being discussed above, with all the engineering wrinkles sorted out.



Flattening chisel back


Honing bevel

https://youtu.be/ADdKsb8_f7I


This is an interesting idea. Any thoughts on its accuracy?

Stuart


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That looks good Ross, but fair dinkum, USD795 for torquey motor that spins at <200rpm, with a foot switch (good idea, but easy to add to any non-ZVR switch)? I reckon NCArcher could rig up a 3 phase motor with a VFD for waaaay less than that. The platter could be a piece of 12mm Polycarbonate.

That would be out of reach for a lot of people but it is the same principle I espoused or near enough. There are others around but we don't see them in Oz. https://www.google.com.au/search?q=h...UIBygC#imgrc=_

Originally Posted by stuP

This is an interesting idea. Any thoughts on its accuracy?

Love the way the stone flies out........

That would work much better if he used Atoma stick on diamond sheets on an oversize piece of Polycarbonate - screw the PC down outside the diamond sheet.

Originally Posted by FenceFurniture

That looks good Ross, but fair dinkum, USD795 for torquey motor that spins at <200rpm, with a foot switch (good idea, but easy to add to any non-ZVR switch)? I reckon NCArcher could rig up a 3 phase motor with a VFD for waaaay less than that. The platter could be a piece of 12mm Polycarbonate.

AND you could make it a man-sized 200mm diameter

Originally Posted by stuP

https://youtu.be/ADdKsb8_f7I


This is an interesting idea. Any thoughts on its accuracy?

Stuart


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That looks like a good use for the flat plate sander I haven't used for ten years and I'm sure I could stop the diamond plate trying to escape as well.

Stuart

I agree with Chris Parks that I could make the mud wasps homeless from my old orbital sander (rendered obsolete with the advent of the ROS). I think four small dobs of blue tack or even double sided tape would be sufficient to restrain the plate. Make a small cutout in the base so a screwdriver could prise out the diamond stone when required.

It would be interesting to try, and for most of us, dirt cheap. Well worth a go.

You could substitute plate glass with W&D or microfinishing film (3M product) for the diamond plates too.

Regards
Paul