ManSpace Issue 3

Issue 3 (otherwise known as Issue 1, 2012) of ManSpace is out now.  Still a massive $6.95, or $5 for subscribers.  An interesting effect on the cover with selective varnishing to highlight details in the images and text.

I have a couple of articles in the current issue: (there are obviously a lot more articles for you to read from other contributors!) A third article has been held over till next time – there was so much content for the current one there just wasn’t the space!

Circle Work: Professing my dislike of a popular power tool, and demonstrating 6 different ways I cut circles in the workshop (excluding handtools, and drilling holes!), whether that be cutting a round disc, or cutting a round hole.

True Grit: which looks at the whole question of abrasives and just how they fit together – sandpaper, waterstones, diamond paste etc – they are all abrasive, and we know to work through the grits but what happens if you don’t have ten different grades of diamond stone?  To complement the article, the following table is what I use to compare abrasive systems.  I have taken a few minor liberties with the numbers, but then no table I have seen seems to totally agree with another anyway.  The other thing you will notice is my table is the only one I have found that places diamond stones in their correct location, and I’ve included some common items to give an idea just how fine some abrasives are.

Waterstones

Description

CAMI (USA)

ISO/FEPA (Europe)

JIS (Japan)

Mesh

Average functional particle size in microns (µm)

P20

18

1000 (1mm)

Beach Sand

28

700

40

P40

425

P60

269

Fine Sand

60

250

P80

201

80

190

P100

162

100

150

100

140

P120

120

125

120

115

P150

100 (0.1mm)

180

P180

82

Portland Cement

200

74

220

P220

68

P240

59

P280/F230

52

P320

46

Silt

325

44

P360

41

120 µm Diamond Whetstone Extra-Extra Coarse

40

Plant Pollen

400

37

320

F280

360

36

P400

35

400

32

400

F360

23

P800

600

22

60 µm Diamond Whetstone Extra Coarse

500

20

P1000

18

600

800

16

45 µm Diamond Whetstone Coarse

P1200

15

1000

14

800

P1500

13

Red Blood Cell

(1200)

12

1200

11

1000

P2000

10 (0.001mm)

25 µm Diamond Whetstone Fine

P2500

2000

8

9 µm Diamond Whetstone Extra Fine

F1200

4000

3

Cigarette smoke

F1500

6000

(4800)

2

3 µm Diamond Whetstone Extra-Extra Fine

F2000

8000

1 (0.0001mm)

P – Coated abrasives
F – Bonded abrasives

Diamonds are a Tool’s Best Friend

Diamonds.

Pure carbon, but not something that is going to upset the greenies, or the skeptics.

The hardest natural element known, it can only be scratched by other diamonds (a simplification, but good enough for our application).  It is not the toughest substance known – good compared to other gemstones, but not as good compared to many engineering materials.  However, it is this hardness that we are particularly interested in for tools – when sharpening, you are scratching the surface (which is where diamonds excel) with increasing finer grades, until a mirror polish is achieved.  If a diamond does fracture, it reveals another facet, and continues to do what it does best.

A diamond whetstone then is a powerful sharpening tool in the workshop.  Unlike other sharpening surfaces, a diamond whetstone actually gets better with use.  Cool huh!

DMT are my preferred diamond product company – they have some innovative products, and use a serious manufacturing process which binds a quality diamond in a high concentration, with a very consistent diamond size – important in sharpening situations (you don’t want deep random scratches from a rogue diamond).

Interestingly, it seems they have not continued with their fine ceramic stone – that always confused me from a diamond specialist company. (Or perhaps it just wasn’t listed on the handout included with my latest shop addition)

So their line up of grades is now:

Extra-extra coarse 120 micron

Extra coarse 60 micron

Coarse 45 micron

Fine 25 micron

Extra fine 9 micron

Extra-extra fine 3 micron

From there, you get into the pastes (and not something I’ve tried), which comes in a 6 micron, 3 micron and 1 micron grade.

They have DiaSharp stones, folding whetstones (plastic covers), Wavy plates (used to match the internal and external radius of curved tools, such as gouges, and the Aligner for kitchen and pocket knives (including serrated blades).

Not everyone wants to use diamond for sharpening, and that is a perfectly acceptable perspective.  I personally like the very soft, yielding surface of the japanese waterstone.  Others are fans of oil stones, or Arkansas stones, or ceramics.  All of these will wear unevenly because of what they are made from, and to get the sharpest surface, you need a flat sharpening surface.

You might use the sandpaper technique – a piece mounted on a sheet of plate glass to produce a flat surface and rub the stone on that.  Or another technique is to rub two stones together.  But there is another solution, and it will be of no surprise, it is a DMT diamond solution.

The latest product from DMT is the Dia-Flat Lapping Plate.  Each plate is hand checked and certified as being flat to +/- 0.0005″ (+/- 0.01mm).  It is the same as an extra-extra coarse stone, but with extra focus on its flatness, and a stripped back to fundamental design to come up with a bonding process to ensure the stone is durable enough to cope with the torture of flattening other stones (oil and water stones).  That inflicts some serious punishment, and this is a stone that laps that sort of punishment up (yeah, a very intended pun!)

At 10″ x 4″, it is an uncompromising size – taking your entire favourite whetstone, and flattening the entire surface in one go.

Check out this video by Stan Watson, the Technical Director for DMT on using the Dia-Flat to flatten a waterstone.

Mine will be subjected to the ultimate flattening process shortly (most likely over the coming weekend)  No more hollow sharpening stones for me!

 

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.

A Slab ‘o Granite

Precision requires precision tools, there is no two ways about it.

Whether it is assuring that your square is square, your plane blades are honed to just the right angle, straight edges are straight etc, it is beneficial to have a true surface to reference off.  Taking that one step further, where it comes to sharpening particularly, if you are relying on a flat surface to create a reference plane (either the surface you use to dress your waterstones for example, or a surface to conduct the Scary-Sharp technique), then you need a surface who’s flatness is assured.

And what better way than a solid slab of granite?  You can get it wet without fear of rusting, it is dimensionally stable through a wide temperature range, and is comparatively inexpensive.

I picked up this tool from Carbatec – a Granite Surface Plate.

Granite Surface Plate

Granite Surface Plate

Measuring 300x230x50mm (12″x9″x2″) and weighing in at around 12kg, the real significance comes in when you look how flat it is.

It comes with a certificate of testing, and in this case, the block has a variance of 0.00008″ (2.1 microns, or 0.0021mm) over 7.5″.  So she’s pretty flat.

Certificate of Testing

Certificate of Testing

It will be featuring in some sharpening episodes in the near future

Comparing Abrasive Systems

It is all very well to say that sandpaper is 100, 200, 600 grit etc, but what does it actually mean? When you talk about waterstones being 1000, 2000, 6000 etc, is that the same as 1000, 2000, 6000 sandpaper?

Unfortunately no! The way that I prefer to ensure I’m comparing apples with apples is to look at the size of the abrasive material itself. This at least should be a uniform way of comparing different abrasives. In other words, I may start sharpening on a diamond stone, transfer to sandpaper, and finish on waterstone. Ok, I may not jump around like this, but there is no reason why you can’t, once you understand the micron size of the abrasive.

I’ve listed here the 2 main sandpaper designations, and the actual micron size of the particles. This will then allow other mediums to be compared.

 
ISO/FEPA Grit designation
CAMI Grit designation
Average particle diameter (µm)
MACROGRITS
Extra Coarse (Very fast removal of material)
P12
 
1815
P16
 
1324
P20
 
1000
P24
 
764
 
24
708
P30
 
642
 
30
632
 
36
530
P36
 
538
Coarse (Rapid removal of material)
P40
40
425
 
50
348
P50
 
336
Medium (sanding bare wood in preparation for finishing)  
60
265
P60
 
269
P80
 
201
 
80
190
Fine (sanding bare wood in preparation for finishing)
P100
 
162
 
100
140
P120
 
125
 
120
115
Very Fine (final sanding of bare wood)
P150
 
100
 
150
92
P180
180
82
P220
220
68
MICROGRITS
Very Fine (sanding finishes between coats)
P240
 
58.5
 
240
53.0
P280
 
52.2
P320
 
46.2
P360
 
40.5
Extra fine  
320
36.0
P400
 
35.0
P500
 
30.2
 
360
28.0
P600
 
25.8
Super fine (final sanding of finishes)  
400
23.0
P800
 
21.8
 
500
20.0
P1000
 
18.3
 
600
16.0
P1200
 
15.3
Ultra fine (final sanding of finishes)
P1500
800
12.6
P2000
1000
10.3
P2500
 
8.4

Waterstones micron sizes are:

1000 : 14
2000 : 7.5
4000 : 3
6000 : 2
8000 : 1.2

So from this we can see that a 1000 waterstone is actually comparable to between a 1200 and 1500 grit sandpaper. And that my 6000 grit waterstones are VERY smooth!

Flattening Waterstones

Been doing a little preparation for a video on sharpening (or part of a series on sharpening to be exact).

One of the popular sharpening methods is using Japanese waterstones, sometimes using a jig such as the Veritas MkII covered recently.

I like to think of sharpness of an edge as the interaction of two smooth planes. The smoother the planes, the sharper the edge. However, you can’t get a smooth plane if your sharpening surface isn’t smooth. In the case of waterstones, this means they need to be flat.

You need to keep on top of this – it is very easy to get dishing in your stone (a patch of increased wear), so a regular flattening (before and after each job would be good practice, and therefore would take little time).

pict6785.jpg

To flatten a waterstone, you can (apparently) rub two together, flattening both, but to my mind this would only really be effective if both stones were the same grade. These are not particularly cheap, so I only have one of each! The stones I have are 1000 grit and 6000 grit. That does not correlate to sandpaper if you were wondering – I will do a separate post about that shortly.

Instead, I prefer to use a known flat surface (in this case 10mm plate glass), and affix some 180 sandpaper to it to flatten the stones. It is prety easy from there – keep rubbing until the stone has a uniform surface. As you can see in the next series of images, I went a bit overboard when first using the stones a few years ago when I got them, and went way too long without reflattening them, which caused significant dishing. I have been using the other side from then on, but for this article, decided to return to the dished side, and get it flat once again.

pict6786.jpg

pict6788.jpg

pict6789.jpg

The first photo is after quite a lot of sanding, and still the hollow is very apparent. The second photo was with the end in sight – the dishing is almost gone. The final photo shows (finally) a nice uniform surface which means the stone is flat once again.

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