True Grit

Being inspired by the recent look at diamond stone sharpening, (which is a topic I have returned to on a few occasions already, covering the different aspects of sharpening), I have again raised a few questions I have wanted to answer, and the more answers, the more questions I find to ask!

One thing that seems to be a regular stumbling block is the issue of the grade of the abrasive material.  So many seem to use a similar system of depicting the abrasive properties of the material in question, but then things seem to not quite line up.

Is a 1000 grade waterstone the same as P1000 (ISO system) sandpaper?  And is that the same as 1000 mesh diamond stone?  Or 1000 grit sandpaper using the CAMI grading system? Sort of, no, no, and that is just the start of the confusion.

Without getting into actual definitions, an abrasive is typically small particles that are harder than the substance you want to abrade.  How they are presented to the item is more a matter of choice than if one system is better than another.  They could be a powder which has some oil added and use on top of a flat surface.  Or in a wax and added to a felt wheel.  They could be secured firmly in a permanent base (although only diamond really justifies this).  They could be in a soft matrix and formed into a flat slab, or turned into a slow spinning wheel, and so on.

I’m still not unconvinced (yeah, double negatives) that I’m on the right track by breaking down all the different systems to their micron equivalent.  So perhaps all abrasive systems should be sold using that designation.  Pick up some 100 micron lapping paste to get a flat side, switch over to 75 then 50 micron sandpaper, then use the 35 then 25, then 20 micron diamond whetstones, really develop a mirror with 15 and 10  waterstones, and finally a 5, 2 and 1 micron diamond paste for a deadly edge.  Wonder if I can market that concept?

Oh, and if you wondered what a 3 micron diamond abrasive can do (which is roughly equivalent to a 1 micron friable product) , have a look at the mirror surface of this chisel, sharpened on the DMT “Steel Waterstone”, which is their finest diamond whetstone (also known as the Ex Ex Fine). That’s an awesome finish!  I’m building a list of items that cannot be purchased in Australia that I’d be rather keen to get to try.  This stone is one of them (as is the Forrest Woodworker2 sawblade).

DMT Steel Waterstone

DMT Steel Waterstone

You just don’t realise how big this topic is until you start really delving into it.  Like every topic in woodworking really.

If you are looking for a bible on the subject, start with Lie-Nielsen’s take on the subject from Taunton Press.

nielsenThe guy who comes up with handplanes like this definitely knows his way around the idea of sharpening an edge!

nielsenplane

In the light of this article, I decided to do a quick audit of what sharpening gear I have, and therefore what is still missing from a good system. And because of my push above, I’ll list them in micron order!

Micron Description Speed
269 A60 Grinder 3600RPM
162 Norton Al Oxide 100 3600RPM
68 Triton WetStone 120RPM
20* DMT Ex Coarse Diamond Hand
15* DMT Coarse Diamond Hand
14 Japanese 1000 Waterstone Hand
8* DMT Fine Diamond Hand
3* DMT Ex Fine Diamond Hand
3 Tormek Honing Compound 120RPM
2 Japanese 6000 Waterstone Hand

*I have amended this list in light of recent discussions with the Technical Director for DMT, and the micron size now listed is based on the size of the exposed diamond, which is what is doing the cutting and not the size of the diamond in total (2/3 of which is buried in the Nickle plating).

Not listing sandpaper of course, although it would be valid to include them.  The finest sandpaper I have is P2500, which is around 8 microns.

I also have a Granite Plate, the Alisam and Veritas Mk2 Honing Jig, a bench grinder and the Triton Wetstone Sharpener.

I wouldn’t mind having a diamond whetstone around 15 micron to fill that gap, and around a 2000 waterstone to narrow the jump from 1000 to 6000.

Alisam Sharpening Sled and Diamond Stones

There are two main aspects of sharpening edge tools.  One is the abrasive, and the other is presenting the tool at a consistent angle to that abrasive.  The more accurately this angle is maintained, the better the result, and the easier the entire sharpening process.  Jigs that assists you in maintaining that angle are known as sleds, or honing guides.

I’ve spoken in the past about the Veritas Mark 2 sled, which runs on top of the sharpening medium.  This sled from Alisam takes a different approach, and runs on a smooth reference surface which the stone is also on.

This concept does not work for waterstones, which although flat can have any amount of tapering, rendering the sled ineffective.  However, it is ideal for diamond stones, where the thickness is very uniform, the Scary Sharp method (using sandpaper), or using powdered abrasives / lapping powders. The guide is therefore not required to travel on or through the abrasive.  I haven’t tried it, but you could imagine the potential damage to the brass wheel of the Veritas if used on the Ex Ex Coarse DMT Diamond stone (which is around the equivalent to ISO120 sandpaper), or having to push over and through lapping powder.

Diamond Stones and the Alisam Sled

Diamond Stones and the Alisam Sled

I have chosen the SS3 Alisam Sled from Professional Woodworkers Supplies here, as it is the lowest of the three, and ideal for the diamond stones I am using. There is the sled (obviously the blue thing!), the 2 DMT Diamond Stones, and an HNT Gordon Plane blade (this is a reject one because it did not meet Terry’s standards, and so I can use and abuse it without feeling I am wasting good steel (the ultimate crime!)) You could just as easily substitute a normal plane blade, or a chisel etc into this guide. I am using a base of MDF, which is remarkably flat because of its manufacturing process.

Setting up for sharpening a plane blade

Setting up for sharpening a plane blade

The guide is set up with the blade roughly in place, before fully clamping down on it.  The black ring (to the right of the blade) is used to set the blade perpendicular to the guide.  Under the stone, you can see two dark tracks, which is where I was already working the blade before taking the photos – this is some of the metal removed from the blade, where it has been forced into the board by the jig.  It doesn’t affect the accuracy, and just shows how fine the particles are that get removed.  There will be little to no abrasive there because of the quality of the diamond stones.  Unlike a waterstone, the diamond stones are not designed to shed the abrasive as part of the sharpening process.

Setting the sharpening angle

Setting the sharpening angle

To set the grinding angle, one handle on the sled is loosened, and the drawn mark lined up with the required engraved angle.  This is not an eyechrometer thing though – underneath the side (as you may be able to make out), there are accurately machined indents which positively engage on raised areas of the jig body, so the angle is perfect, and perfectly repeatable.

Angle Set

Angle Set

Here I have set the angle to 30 degrees, the blade is clamped down (and I’ve moved the alignment ring out of the way, although this was not necessary).

Working through the grades

Working through the grades

You then run back and forward over the stone to grind the blade – one interesting point is in theory if you kept going you would find it cutting lighter and lighter until the blade could no longer reach the stone. This has been addressed very cleverly by having the front two wheels spring loaded – they have a tiny amount of vertical movement allowing more or less cutting pressure to be applied to the blade.  I was quite impressed when I discovered that.  The other beauty of this jig is you can use the entire stone, and not just a half or so, as the jig is not running on the surface at the same time.  I found it a very easy honing tool to use, and it cut quickly because of both the pressure I could choose to bring to bear, and that each stroke used the entire stone length.

Coplanar Guide Wheels and Blade

Coplanar Guide Wheels and Blade

From underneath, you can see the 4 rollers (the right-hand two, which are the forward rollers are the ones that are spring loaded).  The blade in this case is close to being complete.

Flattened Blade

Flattened Blade

This is about as far as I could get on the diamond stones I had.  My next step from here would be to move onto even higher grades of abrasive to really get a mirror finish (and obviously to flatten the back of the blade to the same condition – there is no point having one mirror surface if the back of the blade is pitted, rusty, chipped etc.)

Just a point too on the apparent loss of the hollow ground in the centre of this blade – remember this was a reject blade, and the slight warping made it scrap.  Even so, that is becoming a very well dressed edge, and it wouldn’t take much from here to bring it up to being fully live.

Diamond Sharpening

There are many different abrasive systems used to produce sharp edges on tools, be that sandpaper, abrasive grits, waterstones, oil stones, or diamond stones (among others).  They all have one thing in common, and that is very hard precisely sized particles suspended or retained in a soft matrix.

The quality of the hard particles goes a long way towards the quality of the abrasive.  Strange as it may seem at first glance, this even applies to diamond – there is diamond, and then there is diamond.  For example, the diamonds need to be bound securely into a parent material, if not they come loose, and not only are lost, but can really gouge the tool as well.  Also too, you can have a few diamonds, or a lot, evenly sized diamonds or not, and diamonds that are strong and durable, or ones that easily shatter and shear.

I have sourced some diamond stones from Professional Woodworkers Supplies which have a good name for quality and durability.  They are DMT Diasharp stones, and the ones I have chosen are double sided, so are the equivalent of 4 diamond stones.

For some reason, DMT only categorise their stones as fine, coarse, extra-coarse etc, which is rather frustrating when trying to compare apples with tomatoes. However, I have been able to determine what the equivalent is across all abrasive types, by finding out what the size of the abrasive particles are, which means it is easy to switch and swap between all the different abrasives and still be working “through the grits”. This earlier article of mine on comparing abrasive systems spells it out in a table form.

From the DMT website, I was able to determine the actual particle sizes:

Stone Mesh Micron Effective Micron
Ex Ex Coarse 120 120 40
Ex Coarse 220 60 20
Coarse 325 45 15
Fine 600 25 8
Ex Fine 1200 9 3
Ceramic 2200 7 ?
Ex Ex Fine 8000 3 1

*I have amended this list in light of recent discussions with the Technical Director for DMT, and the effective micron size now listed is based on the size of the exposed diamond, which is what is doing the cutting and not the size of the diamond in total (2/3 of which is buried in the Nickle plating).

Just out of interest, the concept of “Mesh” originates from a sorting method for determining the particular particle size, by passing it through a number of sieves (meshes), with increasing holes per inch (and therefore decreasing hole sizes) until the particle can go no further, so it’s size is known.

Oh, and fwiw, 1 micron = 0.001mm = 0.00004″

When flattening something (whether that be sharpening, or sanding), you start off with a particle size (or grit) which is coarse enough to remove the existing structures and scratches caused by the tooling.  Depending on how rough the surface is to start will determine what is the correct grit to start with, and you keep working till the original machining marks are replaced completely with the scratches from that original grit. You then move onto the next higher grit, and work to remove the scratches from that previous grit.  Rinse and repeat through all the grit sizes until the final finish quality is achieved.  As you work up the grits, less and less material needs to be removed.  One thing I find annoying, is the manufacturers rate their abrasives based on the average grit size.  The problem with that is although the average is all very well, if you have a few much larger particles, they will cause some individual serious scratches which will remain in the project unless you return to a heavier grit and start again.  The better quality the abrasive, the less of a problem there is.

Oh, and one other myth – rubbing two abrasives together to produce a finer grit is just that – a complete myth. Imagine the individual particles of abrasive as tiny chisels.  Do you get a better, sharper, finer chisel by ramming it into another?  No- all you get is a blunt, chipped or broken edge which renders the tool useless.  Same with abrasives.

So onto the sharpening with diamond.  Diamond chips are just another collection of micro chisels.  These are securely bound in a base of metal for the simple reason that because diamond is so durable, you want to keep the diamond particles around as long as possible.  If they are not worn out, why get rid of them?!

The two diamond stones I chose are double sided.  One has an extra coarse side and a coarse side, and the other stone has a fine and extra fine side.  The equivalent in ISO sandpaper is 240, 320, 600 and 2000.  Unfortunately, I feel this already demonstrates a problem, that too many intermediate grits are being skipped.  400, 800, 1200, 1500.  This may explain why when I was using these stones, I found the final result less than the perfection I was hoping for.  Not a fault of the stones themselves, but more may be needed to really perfect the finish.  The lower two were fine, and the jump from 320 to 600 not too extreme, but going from that to 2000 was too much.  However, once you understand micron sizes, it is easy to switch from one material to another.  In this case, I’d probably stop at the fine diamond stone, and switch over to the Japanese waterstones to finish the process. (1000, 2000 and 6000, or in grit sizes: 14, 7.5 and 2). (Update, I now have a better understanding of the grading of diamond stones from the Q&A with the Technical Director for DMT, which covered this point, and demonstrated that there is much less of a jump in the effective micron sizes than I realised)

Part 2 will document the stones in use.

A bit of resawing

For the wood show, I wanted to demonstrate what having a good resaw fence can do for your bandsaw.

Single Roller MagFence

Single Roller MagFence

Using the single roller MagFence, set less than 1mm from the blade (a lot closer than you see in the photo, and I also used a different blade to the one shown), I tried cutting a veneer from Tasmanian Blackwood.

Cutting a veneer

Cutting a veneer

Think I got a pretty good result.  The match is included just for a sense of scale.  I used to do it by eye only, and getting a 3-4mm thick veneer I felt was a pretty impressive result.  Being able to easily resaw a veneer as thin as the one seen here is pretty startling!  And it was simple to maintain the cut width because of the fence.  It is not just veneers that can be cut either – splitting boards in half to have bookmatched panels is as easy.

The single roller is particularly useful because of the bandsaw’s tendency to track, so the operator needs to guide and steer the workpiece to compensate.  Having a fence controlling the width of cut makes this significantly easier.  The other secret is to ensure your blade has good tension.  Running the blades too loose is a very common fault, and results in a poor cut, wandering, and bowing of the blade causing a curved cut.

Sam Maloof

I was sad to hear that Sam Maloof passed away late last week – of course being one of the most influential woodworkers of our age, it never made the news (perhaps some celebrity slept with some other celebrity somewhere which took precidence). Obituaries

Sam Maloof is possibly best known for his chairs, although this is far from the only thing that he made, a Maloof rocker was something highly desired, even by past US Presidents

Photo by George Baramki Azar

Photo by George Baramki Azar

Although at 93, you might expect that he stuck with only traditional tools, I always found it fascinating in the Taunton Woodworking DVD on Maloof that he was not against using any tool that would get him to his desired destination, whether that be the bandsaw or spokeshave, or whatever.

 Photo by Anacleto Rapping / TPN

Photo by Anacleto Rapping / TPN

Photo by Gina Ferazzi/Los Angeles Times

Photo by Gina Ferazzi/Los Angeles Times

There’s a lot of work being done today that doesn’t have any soul in it. The technique may be the utmost perfection, yet it is lifeless. It doesn’t have a soul. I hope my furniture has a soul to it.

– Sam Maloof

Festool Training Workshop

Not sure if I’ve shown this photo before- it is the Festool Workshop and Training Room at Ideal Tools in Williamstown (West Melbourne).  I’d love a workshop that looked like this. I’d love a workplace that looked like this!

Ideal Tools Workshop

Aftermath pt2 – The Wallet’s Response

I did pick up a few things at the show, being conscious of how much I could get on the plane – I knew I had about 12kg spare!

A friend recently showed me a very stylish case he had sourced for the pens he has started making. I still may get around to getting one as well (purchased from the USA) as his one is real leather.  However while at the show I found one that had a similar look and feel, just not leather.

Pen Case

Pen Case

Better get making more pens!

Better get making more pens!

Stores 24 pens in a zippable case, with an internal soft flap to protect the pens on one side from the other.  Cost was around $25 from Carrolls Woodcraft Supplies. Think it is so new that it isn’t even on their website yet.

I did buy a $6 chainsaw bag – didn’t seem a bad price, and it may mean I will look after the chainsaw a little better!

I wasn’t planning on buying much timber – perhaps a few pen blanks, but the Solomon Ebony looked really interesting, and was a surprisingly good price.  I’ve bought ebony before, and gotten very small pieces that still cost quite a bit, and only ever intended to use them for details in other creations.  Instead these pieces are affordable enough to really use them, rather than conserve them.

Solomon Ebony

Solomon Ebony

From left to right, there are some lengths around 18mm square – a bit thicker than normal, but I got them specifically for pens.  They actually came as 2 lengths, but at around 1.5m long, they were going to be tricky to get onto the plane.  I left my run too late to find a saw as the show was packing up, but I found someone with a running chainsaw who was happy to help pop these in half for me.

The next piece is just a nice lump of timber.  The endgrain of the ebony is stunning, and when I do a writeup of the timber itself, I’ll get you some better photos and details images. Same with the stack of 3.

The ebony darkens up to a near black significantly over time as it oxidises, so these pieces will look remarkably different in a year or two!  (I don’t know how fast they oxidise though).  When I turn a pen, if I do a CA finish it will obviously keep the air away from the timber.  Apparently (when I asked about it), the timber will still oxidise over time, it would just take a lot longer through the CA finish.  The gentleman selling the timber had a pen made from it, and it was a beautiful deep black.

The final piece of timber I know nothing about, other than coming from the Solomons, and its name – Kwila.

%d bloggers like this: