Friday, July 5, 2013

Diamonds are a carpenter's best friend

Looking at those horrible photos of my unfinished workbench kinda reminded me that I had intended to actually build some drawers for the thing. Which means that I've got a lot of stock to machine up (I am in no way a hand tool purist) , but before that happens, I've got a secret to tell. I have never replaced the planer blades in my old Delta planer.
Delta 12 inch planer sharpening blades
Good old Blue/Gray
And it shows, big time. Just like not washing the car until it turns green, I was able to put off buying new knives and enduring minor tear-out, for a long time. Then I bought a bunch of Port Orford Cedar (POC). This wood is beautiful and when perfectly planed, leaves a shimmering almost iridescent surface.

Port Orford cedar box oil finish slat top
Port Orford beauty

This is from Merriam-Webster;
adjective \shə-ˈti-ənt\

Definition of CHATOYANT

: having a changeable luster or color with an undulating narrow band of white light <a chatoyant gem>


French, from present participle of chatoyer to shine like a cat's eyes
First Known Use: 1816

REALLY nice stuff, but rather prone to tear-out when planing. Old Blue/Gray could still handle mahogany (amazingly well after 20 years and possibly 1000ft linear with only minor honing) with no problem, but POC? No way. So this last winter, I took a few days and sharpened (hahahahah) the knives with very underwhelming results. Made a jig and and burned through about $10 in wet/dry paper and maybe ever made them more dull. Hard to tell.

So what's different this time? First of all, someone's watching (you) and secondly, I bought some diamond stones.
Cheap import 150 300 400 grit tool sharpening
The first set is a cheap three set no name import special that I got at a local store for $7.95, but you can get them from Amazon for around $12 (2013) delivered. Oh yeah, 2x6 inches and slightly bowed along their length, very flat in width. Those little dot looking spots are actually holes in the metal plate that allow lubrication fluid and metal swarf to get out of the way.  The colored part is thin plastic. Not so good for chisels or things with pointy parts or small surfaces, though. All and all, they are rather durable, very aggressive at 150, 300 and 400 grits and I use them for lots of different things that would ruin my real stones.

3M super 77 cheap diamond sharpening stones
Hold it!

Mount them on some blocks of wood and they flatten right out. Use a good quality spray adhesive like 3M super 77 (16 oz for $10-12) or 90(16 oz for $18). Kinda spendy for glue in a can, but you'll find plenty of uses for it. I can't find a good price with free shipping, so check locally. If you intend to use these stones for precision work like this (hahaha) you might want to check them for uniform thickness along their length and adjust accordingly. I am going to re-do this set, they work that good. A bargain at twice the price.

DMT duosharp diamond sharpening stone
Not as cheap
The second is an 8" DMT Duosharp that I got off Ebay for about $50. It is  a Fine/Extra-fine 600/1200, is also slightly bowed along it's length and flat in width. These little dots are hard plastic that is flush with the diamond coated surface. Still not too great for chisels, though. Really nice when you knock down the high spots (all diamond stones need to be broken in a bit), this stone is a lot more refined than the others. Heavy and stiff means that there is no easy way to flatten it and honestly, if I was paying retail, I would return it to see if the second one that they sent was REALLY as flat as they say it should be. As it was, it was a close decision as to whether or not I should just re-sell the thing, but after I used it for a bit, it grew on me. I guess that I like it well enough to consider spending  $100 on a diamond coated sliver of metal taped to a piece of aluminum (Tsuboman Atoma diamond flattening plate) , so make of it what you will. I hope that Amazon decides to carry them soon. I would love to try one out. One thing is certain, though. I will NEVER go back to wet/dry paper, I'll tell you that.

OK, reference surface.
Perma blue DMT duosharp sharpening jig planer blades knives
Birchwood-Casey Perma-Blue gel takes about 1 minute to apply and turns the metal black which gives you a good reference surface that tells you when you've missed a spot.
Birchwood Casey perma blue gun bluing gel nitrile safety gloves
You're an adult, make your own choices
In the this photo, you can see the tripod stand that I made for planer knives. It's just a block of wood with a tight fitting slot that the blade slips into, attached to a stick about 10" long or so.
DIY sharpening jig guide diamond plate
Fancy, no? No.
Sharpening action DMT diamond plate jig spacers
In use
So as you can see, the jig merely holds the blade at a more or less constant angle that is adjusted by using a variety of spacers underneath the leg. Trial and error, with a bit of measurement, will get you what you need. I would lean more heavily towards the measurement side. You may also notice that the DMT stone sits on a piece of $store shelf liner, which is on a piece of 1/4" float glass, which also sits on more shelf liner. Now that I think about it, there is no reason for the glass really, is there. It must be some sort of permanent muscle memory kind of thing left over from my "Scary Sharp" days. And in case you were wondering, yes the liner material keeps things from sliding around, yes it does introduce slop and contributes towards inaccuracy, and no I am not missing the first joint of my thumb (yet). You can also see a couple of pieces of slate in the background that I use for polishing up the finished edge.

I'll write up a new and improved version one of these days, but for now this is pretty ghetto, but it works. Or you could just buy new ones. Knives, that is. Or a new planer, I suppose.
Delta planer blades sharp DIY
Photo intentionally blurred to hide scratches. Actually my camera hates me.

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Like all of us, I am figuring this out as I go, so when you see something that is incorrect or flat out wrong (and you will!), let me know. This is a learning process. Real people and names, please. Constructive comments and questions are very welcome, but hate speak/politics are not! Life (get one!) is too short.

Thanks, Jason