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flattening chisel backs - question

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Forum topic by HokieMojo posted 02-07-2010 01:54 AM 2289 views 0 times favorited 13 replies Add to Favorites Watch
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HokieMojo

2103 posts in 3190 days


02-07-2010 01:54 AM

I should know this already, but I don’t. I’ve recently purchased a few king waterstones. i’ve got the following grits: 800, 1000, 4000, 6000. On my 1/4 and 1/2 inch chisels, I could use the 800 to remove the machine marks from my craftsman chisel. Then I could easily go through the remaining grits to get a mirror finish. It did take a bit of time (30 minutes for each back) but after getting it flat, the rest of the stones went quickly.

My problem is on the 1.25 inch chisel. I must have spent 2 hours on the back using the 800, but I’m not having much luck. the problem is that when looking at the back, it is convex. It is really tough to get the front edge to start getting smooth. what i’m wondering is this. Do I need a rougher stone? I really want to stick to water stones. i’ve done scary sharp and oil stones, but I really like the water stones. any ideas?


13 replies so far

View papadan's profile

papadan

1174 posts in 2830 days


#1 posted 02-07-2010 01:58 AM

If it is that bad, I would use a slow wet grinder. Then use your stones to finish it.

-- Carpenter assembles with hands, Designer builds with brains, Artist creates with heart!

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a1Jim

115202 posts in 3039 days


#2 posted 02-07-2010 02:03 AM

If you going to use stones an it’s taking that long, Yes you need a rougher stone or you need to do the initial flatting on a grinder.

-- http://artisticwoodstudio.com Custom furniture

View sphere's profile

sphere

109 posts in 2493 days


#3 posted 02-07-2010 02:04 AM

I have used a brass hammer to help coax an unflat back , back into shape. Much as one does to tweak the hollows on Japanese chisels.

-- Spheramid Enterprises Architectural Wood Works

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Julian

880 posts in 2987 days


#4 posted 02-07-2010 03:12 AM

I use a 6” wheel made out of mdf than I put on my slow speed grinder. I apply red rouge to the side and hold the back of the chisel against the side of the wheel. Once the back is mirror shiny I then proceed to do the same thing to the bevel. Both procedures only take a minute to do. I can go from grinding a new bevel to the mdf wheel without changing a thing and produce an edge that will easily take the hair off my arm. I haven’t had to use the scary sharp method since I learned this method and with the mdf wheel I can touch up a dull edge quickly and efficiently so I can back to what I am in the shop to do, work!

-- Julian, Park Forest, IL

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RHutch

5 posts in 2516 days


#5 posted 02-07-2010 04:11 AM

Now that sounds like something I should try Julian.

-- Hutch, Rhode Island

View lwllms's profile

lwllms

555 posts in 2744 days


#6 posted 02-07-2010 04:41 AM

Glue some 60 or 80 grit silicon carbide or Norizon paper to something flat and work the chisel down with that. If you don’t have access to that, cut a sanding belt in half and use it. Make sure and glue it down. It won’t take much effort to remove the abrasive signatures of the sandpaper with your coarse stone but you really want to get that back flat before you move back to your stones.

View 8iowa's profile

8iowa

1546 posts in 3223 days


#7 posted 02-07-2010 05:02 AM

I also like to use water stones. However, for the initial prep of a chisel or plane iron, I have a series of flat glass plates with 50 to 1200 grit paper “gued” on with 3M77. Note, 3M90 is very permanent.

I only go down to 50 grit on old & beat up tools. For a new chisel I would start with 150 or 180 and then progress thru 220, 320, 400, 600, 800, and then to 1200 if you want to finish the surface on the glass plates. I find that 1200 gives a mirror finish on the steel. This saves a lot of wear on your water stones.

-- "Heaven is North of the Bridge"

View JayPique's profile

JayPique

61 posts in 2750 days


#8 posted 02-07-2010 05:07 AM

I do the paper on glass thing as well when I first lap my chisels and plane blades. I use PSA 100, 120, 150 and 180 grit and then move to automotive paper right on up through 2000. I’m a bit picky about it the first time, but you really only need to do it once so you might as well get it right. From that point forward I just touch it up on my finest waterstone – a 12,000 grit Shapton. (Still haven’t sprung for the 30k!)

JP

View RandyMarine's profile

RandyMarine

236 posts in 2831 days


#9 posted 02-15-2010 08:03 PM

Could I glue the sand paper to my Granite top TS? never having used any of this stuff before, does the bonder between the flattop and the paper peel away after?

-- Semper Fi, Randy Sr.

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HokieMojo

2103 posts in 3190 days


#10 posted 02-16-2010 05:11 AM

not what i wanted to hear, but thanks for the honesty. I’m trying a few things to see if i can get the stones to work sufficiently. I’m just out of money to buy anything more, no matter how cheap it may sound. oh well. thanks guys.

View russv's profile

russv

262 posts in 2631 days


#11 posted 02-16-2010 11:16 PM

Hokie,
plain and simple, first time grinding it flat can sometimes take alot. just spray adhesive some cheap 80 grit sandpaper to some MDF and sand away. after that, run thru your wet stones. won’t take long. after initially flat, you won’t ever need the 80 grit sandpaper (or MDF) again. the sandpaper on mdf will work fine, cheap and fast.

russv

-- yknotwood.com: where to go because you don't want no stinking plastic!

View rwyoung's profile

rwyoung

388 posts in 2934 days


#12 posted 02-16-2010 11:55 PM

Hokie -

Make sure your stone is FLAT while you are working on the backs of the chisels. If you are working at a chisel for that long, you are probably also putting a hollow in the stone. Stop once in a while and flatten the stone.

-- Don't sweat the petty things and don't pet the sweaty things.

View rtb's profile

rtb

1101 posts in 3175 days


#13 posted 02-17-2010 12:02 AM

For old or really beat up one I like to flatted then on the belt sander and then go up thru the grits

-- RTB. stray animals are just looking for love

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