Belt Sanding Chisel or Plane Iron Back?

[Steve Friedman]

The piece was found at the local monument maker, (tombstone cutter). The guy let me have it for $25 and helped me to get it in the car. Someone estimated by the approximate volume that it is about 150 Lbs. If you go this route you may want to bring a straight edge with you to select the best piece.

Here is how it got home:

Attachment 295990

That is in the back of a Chevy Tahoe.

I learned a lot from my father about handling heavy loads. My folks had a furniture and appliance store and I was often used as a delivery person.

It was carefully slid out of the back of the car onto a hand truck. it was then positioned to lean on one end of the horse. The free end was carefully lifted and slid on to the horse. The abrasive hasn't been changed in awhile. It was used recently to clean the back of a chisel and the sole of a K3 plane from last weekend's rust hunt.

jtk

Thanks Jim,

It may be weird, but I may need to go visit some local monument places. Not sure what they're called, but I have seen pieces in cemeteries that are shaped like that bordering the grave sites. Thanks.

Steve

[ian maybury]

As Jim I've had good luck getting granite offcuts from local monumental masonry place too. That long piece looks like a great idea. Even larger sized surface plates from China these days have got very cheap too.

Recent experiments here suggest that what works best depends quite a bit on the size and type of chisel or plane blade, and on how much metal needs to be removed to flatten it - and that what works well on smaller hollow back blades is too slow for wide flat ones.

I've had great luck on Japanese chisels flattening backs on the top of the disc on a WorkSharp with the stock 80 or 120 grit discs or diamond lapidary discs (like a slightly smaller version of the Veritas Mk 2 power sharpening system) - then on to 400 grit before the waterstones. Narrower Western chisels that don't need a lot of metal off the backs work OK on it too. It's probably 2 or 3 times faster than a 120 grit waterstone.

Larger areas/wide blades, tougher steels, more depth to remove and non-hollowed backs can need something a quite a bit more aggressive/slower to burn up self adhesive abrasive paper. Then there's lot more risk of overheating, dubbing and doing other damage in a moment. It's all in the judgement and the touch.

Inspired by Derek's rig I cut a new bevel on an A2 plane iron at low speed on a stock Bosch belt sander on 120 grit AlOx last night, and got close enough in a few minutes that i could quickly finish it on the WorksSharp and then on a coarse waterstone - but realistically it was living dangerously and needs a flatter and harder platen than stock to be properly controllable. Seemed to remove metal 2-3 times faster than the WorkSharp depending on the grit. It would be no use for flattening backs as stock - they just wouldn't come out flat enough. It stayed surprisingly cool though. Lots of potential to end up with bleeding/sore fingertips..

I've had good luck with a UK market Record disc sander with 80 or 120 grit self adhesive AlOx paper on the disc to flatten the back on some wider (1 1/2in etc) cheap Western chisels and gouges that needed a lot of metal removed too. Similar rate of metal removal to the belt sander, it also stays cool if cut in short bursts (aluminium disc), and is dead flat and a solid surface. Also risky for the fingers without jigs. Im in the process of building a rest to accept a honing guide (a la the top of the disc on the WorkSharp) and/or other grinding aids (I have quite a few of the Tormek jigs) to take some of the risk of messing up blades through poor control. Probably shorter abrasive life due to the reduced area, and definitely slow self adhesive grit/paper changes compared to a belt are factors - but it has potential if as in my case you already have one.

Chances are that a highly variable speed belt with a flat and hard platen, and quick change belts may be close to a (cheaper) universal solution. Or maybe one of those larger water cooled horizontally mounted waterstone disc machines with lots of spare stones in different grits in a high very budget scenario?

ian

[David Weaver]

With a belt grinder, belt use isn't so much of an issue. Most of the stuff we grind is well ground with cheap aluminum oxide belts. I ran off a third of the thickness of a 2 1/2 inch plane iron with a 1x42 80 grit generic belt. The real issue when you're grinding like that is to have the discretion to grind a little and keep the iron cool, because you have the urge to really remove a lot.

This is something that you do only when a blade is too far gone for anything else (including loose diamonds on a lap). I rarely do it, there is still a fair bit of hand work left after you do it - another 10/15 minutes worth to get things dead flat. It is something to do for irons that are complete lost causes, well beyond the condition you'll ever find any new tool.

Pat - in regard to the flatness comment, the part where it really counts is right at the edge of an iron. if you can't get your stone on the back of an iron to move a wire edge, you have to either finish with superfine abrasives or strop like crazy. It's a lot nicer to thin the edge with a fine stone than it is to remove a very thick wire edge by stropping.

[Pat Barry]

Pat - in regard to the flatness comment, the part where it really counts is right at the edge of an iron. if you can't get your stone on the back of an iron to move a wire edge, you have to either finish with superfine abrasives or strop like crazy. It's a lot nicer to thin the edge with a fine stone than it is to remove a very thick wire edge by stropping.

Thats the same message I was going for when I said

Just get the cutting edge right. That's the only way a pit or two will cause a problem.

[Winton Applegate]

post that mentioned use of a belt sander

We were talking about belt sanders but this "belt" is stationary and the blade is moved over it by hand force.

You may be thinking of Derek's fine blog entry.

[Casey Gooding]

I have used a belt sander on irons and chisels in bad shape. Generally OK results as long as you know you will have to do more work by hand. A ceramic belt helps as it won't wear out as quickly as many others.

[ian maybury]

For sure stock (faster running) belt sanders and discs (even if they have flat platens etc) tend to come in right on the upper end of metal removal rate and risk of heating/dubbing/limited precision and flatness/sanded fingers - and hence require lots of caution. So perhaps best reserved for use with care on jobs requiring large volumes of metal removed over large areas.

I'd be reluctant to try doing very much on e.g. a narrow (say 3/4 in and smaller) chisel on a belt unless there was the option to reduce the speed right down, and if required change to a finer grit belt. (below maybe 800 ft/min) - which seems to be the way the purpose made belt sharpening systems like the Sorby are set up http://www.robert-sorby.co.uk/proedge.htm This is roughly the surface speed of the Work Sharp too.

That same set up would seem quite slow on the back of e.g. a 1 1/2 in western chisel or a badly out of flat plane blade though unless it was reasonably close to flat as received. (but would likely be a big mistake with/would probably actually worsen e.g. an already lapped/very flat as delivered Veritas/Lee Valley blade that only needs a few minutes on a flattened 1,000 grit waterstone to get it ready to polish)

Speed may not be so important on a one off job, i'm probably a little sensitised having just finished setting up a whole set of Japanese chisels and a bunch of older Western ones. Some of the wider Western ones were badly bellied.

Chisels come with a handle that gives good control, but i'd be cautious about trying to flatten the back of even a rough old plane blade on a belt sander unless it was set up with a flat platen, and especially not without some sort of handle to help with handling it. Lots of risk of doing more harm than good, and there's other options. Jim's long abrasive strip on granite/Derek's abrasive strip on glass http://www.inthewoodshop.com/Woodwor...%20Blades.html, or presuming no ideological opposition there's the ruler trick to polish just the area adjacent to the edge on waterstones. (see the latter part of the other thread on suction)

[Brett Robson]

This guy has the belt sander sharpening technique down -- can't see anything wrong here!

https://www.youtube.com/watch?v=aKzZ6-dQ2C0

[David Weaver]

Do you think that video is a work (intended to be dumb?) or do you think that guy was serious. It's been posted places several times....if you've ever sharpened something trailing or against a hard wheel like the roller on a belt sander, it can turn things cherry red. (maybe I should say ground instead of sharpened).

[Steve Friedman]

Do you think that video is a work (intended to be dumb?) or do you think that guy was serious. It's been posted places several times....if you've ever sharpened something trailing or against a hard wheel like the roller on a belt sander, it can turn things cherry red. (maybe I should say ground instead of sharpened).

I thought it was a joke as well and expected him to hold up a blued chisel at the end. I have blued lots of steel with a lot less heat than that. The chisel is obviously getting very hot. At the 1:14 mark, you can see him flinch when his fingers are near the edge of the chisel. For the next 25 seconds or so, his fingers keep moving farther from the edge of the chisel until he leaves at 1:40 to put on gloves. Looks like a plain Marples chisel, but maybe it's made from some kind of magic steel. I don't have any magic steel chisels, so I won't be trying that anytime soon.

Steve

[Tom M King]

I use various grades of this Wet-or-Dry on a granite surface plate for flattening. It lasts many times longer than the hardware store variety, and even at the price per sheet, it's probably still cheaper than buying the cheap stuff in the long run. I don't know that it cuts any faster, but it definitely lasts longer. Most of the time, one grit gets rinsed off, and allowed to dry hanging on a line until the next time it's needed.
http://www.multitechproducts.com/100...dry-sandpaper/ Or 3M Imperial AO for the finer grits.

Final polish is done on stones, and finished on Diamond Lapping Film.

I've never bothered to flatten the whole back of a chisel or iron. It doesn't take very long if you don't do but the last inch or two

[ian maybury]

I'd be very cautious of the belt speed and amounts of time he grinds for without cooling in water too. Especially at the bevel. Once the main body of the blade gets hot enough to be hard to handle it's very easy to overheat an edge - having burnt lots of other tools over the years I prefer to keep the body cool/cold so there's always a heat sink available to cool the edge area.

That said belts don't heat that badly, and he may be used enough to doing it to get away with it. Or he may just have polished off the blued/burned bit at what is a pretty thin bevel - hard to see. Either way he's on a relatively fine (120 grit he said) belt that's quite worn, over a flat platen, and it's quite a wide chisel. It'd be a much more difficult/probably impractical job on fresh 80 grit with a narrow chisel. i.e. it's a lot to do with the specifics.

It demonstrates nicely the point that when a large area is in contact/there's a lot of metal to be removed from the back of a blade that even quite an aggressive belt (or disc) is with enough skill fairly controllable. Provided the back of the blade is got down into contact with it neatly - without knocking a corner off or something (a wrong touch could destroy a tool), and provided the back is bellied so that it's possible to sneak up to and instantly stop at the cutting edge before overheats. It'd be much more controllable and a lot less risky if the belt was running much more slowly. It's not the way I'd want to try to flatten the back of my (mythical) $400 Japanese chisel....

[steven c newman]

Just finished up working on a Ohio Tool Co. tapered iron for a coffin smoother. Set the guide to 30 degrees and gave the iron a ride on a worn down 80 grit belt sander. Cup of water was nearby. Ground the bevel until a wire edge had started. Then went to a 220 grit on a tile, still with the guide in place. Then three wet7 dry papers of 1500,2K, and 2.5K. Back and bevel both.

Reset it up in the smoother, had it a bit rank, but it did gave a nice full width shavingIMAG0183.jpg

This was the $5 one i found. It was missing a bolt for the iron. Got a tap and made a new bolt as well
IMAG0186.jpg
Tap was a 10-1.5 Metric Plug type. Bolt was a 6mm allen wrench to tighten. Came from a shelving system they use at work. Had to shorten the bolt a bit, to clear the wedgeIMAG0187.jpg

Edge of the iron seems to be sharp enough, and the back shines like a mirror. Not even a mark in the shaving
IMAG0188.jpg
Yep. I think it just might work, IF I can adjust it a little bit better.

[Chris Fournier]

Things get hot really quickly on belt sanders, you could easily draw the temper out of your tool steel so caution is required. Personally I don't think that this would yield accurate results in your average shop.

[Pat Barry]

Edge of the iron seems to be sharp enough, and the back shines like a mirror. Not even a mark in the shaving
IMAG0188.jpg
Yep. I think it just might work, IF I can adjust it a little bit better.

Holy cow Steven. Very nice work finishing off that table top. I don't think you need to do much more with that iron. Great job!