Mechanized back flattening

Re: Mechanized back flattening

John Truxell-Svenson

>I can't directly answer the mechanization question, but have seen mention of using the LV system or even the Makita horizontal wet grinder; someone who uses those can pipe up about pros/cons. What I can offer is that I have had success with flattening 1" chisels that were badly out of flat just using a seriously coarse (220?) waterstone.

Your mileage will be different with half-again the surface area, but the coarse stone removes material *very* quickly; I have never had to spend more than 15-30 minutes on anything before moving up the scale. The only tricky part is [hijack bait] working with a flat coarse stone so that you aren't creating more of a problem; 90-grit SiC powder on one of the three level spots on my garage floor works fine, and another ~10 minutes at 1000 gets things ready to polish.

Ignore if you have already tried/rejected this, but $20-40 for a "green" stone is worth a shot before investing in power if you haven't.

/jvs

Just stick to it !!

Luke Herzberg

>Last time I was sharpening some chisels my fingers were cramping up, both in the flattening process and trying to hold the bevel flat to the stone. I grabbed my can of Super 77 (rubber cement in aerosol) and sprayed the chisel, basically gluing my fingers to it. It made things much easier and less fatiguing because not as much gripping pressure was required. It all cleans up with WD-40 also...doesn't WD-40 solve all problems? : )

- Luke, wondering if this is how Edward Scissorhands got started...

Re: Mechanized back flattening

Russell Seaton

>I have the Veritas Mark II sandpaper sharpening thing. I can and do flatten smaller chisels and plane irons with it. I have tried unsuccessfully to flatten 1.5" and 2" chisels. And I've tried the Makita belt sander too. I have not had much success with either power method for large chisels for some reason.

Re: Just stick to it !!

Tom MacGregor, Vermont

>No, some things require Duct Tape.

Re: Mechanized back flattening

Joshua Clark

>I've posted this before, though maybe not here at WC. The best way I've found to flatten the backs of chisels, plane blades, etc is to use drywall sanding screen or mesh. You can find this stuff in the drywall section of any HD, Lowes, etc. The mesh is coated with SiC and comes in various grits. I usually use #220. The open nature of the mesh prevents clogging and the SiC cuts _fast_. Using drywall screen I'm able to flatten a badly pitted chisel in just 1-2 minutes. From there it's on to a 1000 then 4000 and finally a 8000 grit water stone for a mirror-like finish.

I picked up this tip from Tod Herrli at a plane making class a few years ago. I think the tip was also featured in Popular Woodworking a few months ago as well.

I've tried several mechanized methods for flattening backs as well. I purchased the Makita horizontal wet grinder just for this purpose and it works well, but it's expensive and the stones do need to be trued after a while of flattening backs. It's also slower than the previous method. With the 1000 grit stone it usually takes 5-10 minutes to flatten a chisel or blade. I have the 220 stone, but it tends to glaze over very fast. One big advantage the Makita has is it lets you to sharpen your big miter-trimmer blades using the jointer blade attachment. I suppose you could sharpen your jointer/planer knives as well but that's for another message board!

Good luck!

-Josh in CT-

Re: Mechanized back flattening

Lyn J. Mangiameli

>I have tried mechanized means of back flattening and have always found them to cause more problems than less. For one, with most items, the entire back can't be flattened, which makes any future back flattening (and removal of sharpening burrs) more problematic. Second, as you have found, even a slight bit of momentary misalingment can ruin you attempts to acheive a flat back and require a lot of time to correct. The latter problem could be minimized if not eliminated with a proper jigging system, but at present no one offers one (I did toss out an idea for one to Rob for the LVPSS, but I don't know if they will pursue it or something like it).

My recommendation is similar to one of the earlier replies, namely that you obtain one or two very course stones. My experience has been that many blade backs are far more out of plane than one would expect, and it takes some serious metal removal to get them to a point where one is refining the surfacer, rather than flattening it.

My standard procedure is to start with a 1000 waterstone, and take a look at the pattern it leaves on the back. If the pattern suggests that the blade is going to require much flattening, I immediately drop down to a 100 Shapton stone to get the back flat quickly and efficiently, and then go back up through the stone ranges to refine the surface. In my case this might be 100, then 200 or 320, then 1000, then the finer stones.

I think you will find that having just one efficient coarse cutting stone like the Shapton 100 will remove the tediousness form flattening the backs of all but the exotic steels (A2, M4 etc.).

I suspect that diamond slurries my be equally efficient for these purposes, using much the same grit ranges, but I just have less experience with them than I do with waterstones.

Re: Mechanized back flattening

David Linnabary

>Gotta agree with Lyn, seems like a lesson I had a hard time making myself belief was that it is often faster to start with a coarser grit and walk back up through the grits.

Also spending too much time on too fine of a stone just puts that stone out of flat sooner and since your coarser stones tend to be less expensive it makes even more sence to do the heavier cutting on those.

David

Re: Mechanized back flattening

David Linnabary

>My heavy cutting surface is a piece of marble window sill which is about 5" x 30" and I use 4" wide roll type PC adhesive backed paper, usually 80 grit. The advantage for me is that once I get a proper grip on the tool the long surface seems to make the work go faster with less tendancy to rock at the end of each stoke and it's less tiring. It's especially good for flattening plane soles.

I'd suggest checking with your local countertop installation company and see if they'll throw you some scrap.

David

Re: Mechanized back flattening

Alan Hamilton

>Robin,

I have a Makita machine, and I have used it to flatten the backs of some edge tools. My Makita doesn't really shine at flattening backs though. "Sticktion" is a big problem--especially with plane irons--and it can be difficult to keep the back of narrower tools flat on the stone.

It can be done on a Makita, but I no longer use mine to flatten the backs of tools (I rarely use my Makita for anything these days). I've reverted to a green stone and a measure of patience.

Alan

Stone Flattening

Don Thompson, Cutler Ridge, South of Miami FL

>IIRC, you like to flatten your flattening stones with diamond plates. Do you still prefer this, and, if so, which diamond plates do you like to use?

new thread! new thread!

John Truxell-Svenson

>...or, as Opus used to say, "ppphhhttt!" :)

Hey, Joshua

Todd O. Cronkhite Native of Maine

>What do you mount your drywall screen to, and how?

Todd O.

Re: Mechanized back flattening

George Huron

>Start with 80 grit adhesive backed sandpaper on glass until most if not all of the back has the same scuff marks. If the back close to the cutting edge is too rounded, you may have to cut some of the chisel off and regrind the bevel to save the chisel. Use an abrasive wheel saw (I have only used an industrial abrasive wheel saw). The saw I used had a clamp to hold the chisel in place while the cut was made. I don't know if I would hold the chisel by hand because the forces would probably be too great for me to hold the chisel steady.

Re: Stone Flattening

Lyn J. Mangiameli

>Hi Don,

I use any 'ole perforated DMT that is handy, generally a Black or Blue one (the two coarest). I have the Shapton lapping plate and find it works fine, but I tend to only use it at the end of a session when I don't have to worry about the lapping grits contaminating my stones as I will have plenty of time to clean them off. With the diamond stones, I don't have to worry about this contamination.

It's a good solution for me as I already had the Diamond stones and don't find them efficient for blade maintainance, thus this is a good way to use them up.

Re: Mechanized back flattening

Bob Foster

>the fastest method I've found is a disc sander,but you can't bear down to hard or to long or the temper will come right out. The safest machine I have Is a 4" wide wet belt sander made for grindig glass. It has a 15" long platten and a water drip.

Re: Mechanized back flattening

Steve knight

>I can do 2" on the makita no problem. but I have had a bit of practice (G) but my backs are not much out of flat. if I had a lot to remove I would use sandpaper on the nakita. I have a 80 grit setup for hogging steel.

Re: Mechanized back flattening

Steve knight

>You just need mroe practice I will send you 100 more planes irons to practice on. I will even pay you 1.00 each to polish them up (G)

I can take pics on how I hold the irons if anyone wants ot see it.

Re: Stone Flattening

Steve knight

>Just start with the fine stone and work your way down. I don't have any contamination problems. I just rince the stones when done. then I take a air hose and dry off the lapping plate.

I hope to get ritch enough to afford the new diamond lapping plate.

Re: Mechanized flattening - followup Q for Steve

Murray in Palo Alto CA

>Steve,

What are you using for the sandpaper base on your makita? Did you pickup some sort of a jeweler's plate?

Re: Mechanized back flattening

Murray in Palo Alto CA

>Steve,

I'd like to see those pics.

Thanks,

Murray

Would a hacksaw work?

Robin Frierson

>That was a problem with this chisel. The corners were very rounded. After I tired of back flattening I decided to just grind the bevel down to get past the problem area. And on the Tormek(my only grinder) it was slow going. I finally decided to set the chisel aside and come back to it another fine day.

But In the future I think just cutting off the end sounds like a good idea. Would a hacksaw work? Or is the tool steel just as hard as the hacksaw. An abrasive wheel you say. And what kind of tool do I run the wheel on. I imagine that would get kind sparky?

Re: Mechanized flattening - followup Q for Steve

Steve knight

>I had tried diamond laps on the makita. worked great for about 30 plane irons (G) but I just used one with PSA 80 grit zirconia cloth. I think they cost me about 3 or 4.00 each. I get about as much life as the diamond. Been thinking of trying some finer stuff but I have not done it yet.

Me too

Robin Frierson

>You do your backs on the Makita if I recall correctly Steve? How many Makitas do you have now? I too would like to see how your do it.

Re: Would a hacksaw work? *LINK*

George D. Huron

>An abrasive wheel saw is a tool. It looks like a simple chop saw but it is designed to cut metal with an abrasive blade. A hacksaw cannot cut chisel steel. The chisel metal is much to hard. If it is only 1/4 inch or so that you need to remove from the length, you can grind this off on a conventional grinder in no time. Just do it in steps cooling the blade by dipping in water periodically so as to prevent overheating.


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