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Forum topic by TMcG posted 757 days ago 814 views 1 time favorited 13 replies Add to Favorites Watch
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TMcG

182 posts in 1601 days


757 days ago

Topic tags/keywords: sharpening waterstones flatten question

Looking for some guidance on sharpening, specifically flattening the backs of my plane irons.

I have waterstones, 400/1000/2000/5000/8000 and a granite block to flatten them.

When trying to flatten the backs of the planes I always seem to end up with some sports that are shinier or more polished than others though the scratch patterns are consistent and uniform across the back of the iron.

Are the shiny spots indicative of high spots or is that just something that happens as you flatten ?

I just can’t seem to get them consistently polished across the whole back of the iron and, to be honest, it’s driving me crazy and keeping me from getting to the parts of this hobby I really like.

So, sharpening guru’s, any thoughts as to what I’m doing wrong or questions that can help illuminate what I’m doing wrong ?

Thanks in advance
tony

-- http://wood.mcgivern.org


13 replies so far

View a1Jim's profile

a1Jim

112000 posts in 2178 days


#1 posted 757 days ago

He Tony
It sounds like your putting to much pressure on one side while your sharpening. A little gun blueing on the the back will give you a very good indicator of how your doing.

-- http://artisticwoodstudio.com Custom furniture

View BubbaIBA's profile

BubbaIBA

171 posts in 977 days


#2 posted 757 days ago

Tony,

I’ve found it difficult to flatten on waterstones, they dish much too easily so as you move from one grit to another they have different flatness. For flatting, what works best for me is either sandpaper on granite or diamond stones. I doubt you are doing anything wrong, it’s just your equipment letting you down.

View Loren's profile

Loren

7253 posts in 2249 days


#3 posted 757 days ago

The only part that needs to be flat is near the edge. Depending
on the individual chisel or plane iron, it’s sometime not worth
the effort (to me) to flatten more than the 3/4” or so at the
edge. In a spectacularly swaybacked chisel the lack of a flatter
back may impede usefullness in some cuts, but such deformed
chisels are usually not much good anyway from a metallurgical
standpoint.

All you need to do is get the back flat enough that it can be
polished at the edge to the same grit you hone the bevel
to. Depending on your skill at honing the bevel, you may or
may not be able to get a consistent “shaving sharp” edge,
but that has at least as much to do with your technique
as a fine polish on the back.

If flustered, do the best you can on the back near the
edge and buff the back with jeweler’s rouge.

-- http://lawoodworking.com

View LukieB's profile

LukieB

921 posts in 931 days


#4 posted 757 days ago

I start with a piece of 120 adhesive backed sandpaper (porter cable makes some, available at amazon) on a scrap of granite (from a local countertop company and free). Flatten until the shininess is even, and then move on to the waterstones. I also use the granite and sandpaper to flatten the stones. And I’m very happy with the results (huge bald spot on my arm, from testing plane irons)

-- Lucas, "Someday woodworks will be my real job, until then, there's this http://www.melbrownfarmsupply.com"

View TMcG's profile

TMcG

182 posts in 1601 days


#5 posted 757 days ago

Thank you all, I am only flattening the last 1” or so of the iron

The waterstones certainly do dish quickly, perhaps I’ll get some diamond stones, got everything else ! :-)

So are you “bearing down”, as it were, or is the weight of the iron and you’re just sorta guiding ?

-- http://wood.mcgivern.org

View ShipWreck's profile

ShipWreck

536 posts in 2353 days


#6 posted 757 days ago

You dont need much more than the weight of the chisel itself to sharpen. No need to push down very hard at all.

Forget the 400 stone, it is way too soft and a waste of money. 220/400 Sand paper works better because it will not dish.

View Clint Searl's profile

Clint Searl

1389 posts in 962 days


#7 posted 757 days ago

Tony, it sounds like you’ve bought into all the hype about sharpening that’s uber fashionable these days. In my 40+ years of woodwork, oil stones and wet/dry sandpaper on a piece of glass have served to deliver all the sharpness that’s necessary.

-- Clint Searl.............We deserve what we tolerate

View TMcG's profile

TMcG

182 posts in 1601 days


#8 posted 757 days ago

thanks Ship, that helps, I’ll give that a try.

Clint, sigh, I’m just trying to learn how to flatten some plane irons and chisels so I can get better at something I’ve grown to really like, bought into all the hype ? Really ? I’m glad you’ve got all this down pat, 40 years of experience’ll do that for you I guess.

-- http://wood.mcgivern.org

View a1Jim's profile

a1Jim

112000 posts in 2178 days


#9 posted 757 days ago

I agree that the scary Sharpe system works great and it’s low cost and simple to do.

-- http://artisticwoodstudio.com Custom furniture

View ShipWreck's profile

ShipWreck

536 posts in 2353 days


#10 posted 757 days ago

I forgot to add that you only need to flatten the back of the blade/chisel about 1” from the edge. Going any further is just eye candy.

View sikrap's profile

sikrap

988 posts in 1960 days


#11 posted 757 days ago

I had the same problem for a long time. How I fixed it was by making a jig that holds the iron in place while I flatten/polish the back. All I did was take a piece of mdf about 3” x 5” and inserted 4 1/2” rare earth magnets into it with epoxy. Cost me about .40 and it works great. In fact, it works so great that I’ve made several and I give them out to people that take my sharpening class at the local woodworking club. If I can remember, I’ll post a pic tomorrow. Another great thing about this is that its much more comfortable :)

-- Dave, Colonie, NY

View TMcG's profile

TMcG

182 posts in 1601 days


#12 posted 756 days ago

Jim, I do tend to agree that the Scary Sharp system is a lot simpler and definitely a lot less messy ! But, by chance more than anything, I started down the waterstone path as part of a gift, so here I am

Shipwreck, I’m only trying for the last 1” or so

sikrap, That sounds great, would appreciate the pic

-- http://wood.mcgivern.org

View sikrap's profile

sikrap

988 posts in 1960 days


#13 posted 756 days ago

Well, it turns out that I lied. The magnet are 3/8”. All you do is clamp the mdf down and drill 4 holes with a forstner bit, drop a drop of epoxy in, drop the magnets in until they’re flush with the mdf and you’re good to go. You’ll be amazed at how securely these itty bitty magnets will hold a plane iron and how much easier this simple jig makes flattening/polishing the back.

Well, I’ve tried several times to upload the pics, but it just ain’t working for me. PM me with your email address and I’ll send them to you

-- Dave, Colonie, NY

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