Get out of jail card

It is Sunday, (or after trading hours), or simply live too far from your normal woodworking supplies shop, and your drum sander has run out of abrasive.

What do you do?

I decided to find out if there was an alternative, if only temporary to get you out of trouble so you can finish the job you are doing.

Headed down to Masters to see what was on offer.  Seriously….very little.  Certainly no cloth backed sandpaper in a roll or of any length.  About the only stuff I could find was a very weak paper backed painter’s sandpaper.  No idea how it’d survive – you just touch it and the abrasive is flaking off the backing.

Went to take a length anyway, and discovered that even worse, it is perforated every metre (for easy tear-off – the last thing you want for a machine sander!)  But there was nothing else, so it was either this to get out of jail, or nothing.  It wasn’t the right width either, so it was going to be an interesting attempt.

First, I took some packing tape, and ran a length down the entire back of the 2m long strip I bought.  Oh, and the strip cost $4 ($2/m), compared to something like $18 for the real deal.  (Remembering this is a temporary fix, not a long term viable alternative).

With a bit of guesswork, I trimmed the end to an angle, then with a bit of adjustment got it so each loop butted up against the previous, and got to the opposite end of the drum.  That was a lot easier, as the end was simply trimmed to be parallel to the edge of the drum, and secured with the second clip.

IMG_4209

Kind of looks the part doesn’t it!  Also proves that you can use other widths of sandpaper – you are not restricted to just using a 75mm wide roll (think that is what the standard width is).

A quick test – turn on and off (while standing clear) – seems to work – it didn’t fly to shreds instantly.

Next test – sand something!

IMG_4210

Took a scrap of timber, and ran that through.  It survived as well, even multiple passes.  You can see a gap at the right hand side- I hadn’t gotten sufficient tension in the roll, so after this pass I readjusted the paper to get it tight on the drum again.

IMG_4211

After a few passes, the wear is a lot more evident on this sandpaper than is on the garnet cloth-backed sandpaper.  However, it was working.

So let’s do it for real.  Got the piece of walnut that I needed to sand, and ran it through again, and again to flatten it off.  I did go with a slower feed speed and less height change between passes to give the paper the best chance for survival.  Even so, near the end of the job the drum was bogging down a bit as the paper was loosing its ability to cut.  But I got the piece flattened (over a dozen passes)

Turned it over to dress the rear side a bit, and managed to get about three passes in before the paper exploded off the roll.

It wasn’t dangerous – the paper was flapping a lot on the drum, but there was no issue in turning the machine off.  There were bits of sandpaper everywhere (about 1″ square) – when this let go, it really let go!  Surprisingly, the perforated area halfway along had survived (although had started to tear when the length failed).

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The proof of concept was achieved however – I have a nicely sanded piece of walnut – so this indeed “get me out of jail”  It isn’t the most economic – an $18 length will last and last (until you burn it or do something silly, or wear it out), but for a one-off when the shops are shut, this worked.

Be your own judge whether you choose to ever do this for yourself or not.  I am satisfied that there was no real risk (and I stood aside even so).  If I have to do it again, I may try gorilla tape next time – something a bit stronger than a cellotape-type packing tape which may increase the time the temporary fix can survive.

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

The Camera is (still) Mightier than the Pen

There is a pen style to suit everyone, from the thinnest slimline designs, through to the bulkiest, heaviest ones.  The price can vary from a few dollars to $100 or so, simply for the mechanism.  You’d certainly want to be on your turning game when working with the expensive models.

Elegant Beauty Kit

There are stacks of different pen kits out there, from slimlines, through sierras, sedonas to emperors and on and on.  Some require one turned section, some 2, either the same diameter, or with lids, or other sections.

Sedona Kit

Some are more complicated than others!

Blank Drilling Vice

A blank drilling vice holds the blank steady, and parallel to the drill bit.  Until recently, I used a standard metalworking drill press vice which was ok, but this style of dedicated vice eliminates the problem of ensuring the blank is actually vertical.  It also makes it easy moving from one blank to the next, or to remount a blank for redrilling.  Changing to a larger or smaller blank is easy – certainly no harder (and I’d say easier) than a standard screw vice.  The quick-action lever is a definite boon.

Tube Inserter

This simple tool is a tapered shaft, and allows the brass core to be inserted without you directly coming into contact with the finger -joining Superglue!  I tend to find it also prevents over-insertion, where the brass tube sticks out the other side (and the speed the glue sets typically prevents a fix).  However, it is a rather gentle taper, so is not as effective for the larger tube diameters.

Pen Mill

Once the tube is inserted, and the glue set, it is time to dress the ends so they are flat, and perpendicular to the tube (and therefore the components).  Some mills have different diameter central bores for the different pen types.  This helps keep the mill accurately aligned, and also cleans out any glue (etc) that happens to have gotten in where it shouldn’t have.  However I still haven’t found a mill that I am happy with.

Pen Mandrel

Have a couple of pen mandrels here – the top one is variable (ie has variable length with a chuck)  The mandrel is critical as it supports the blank as it is being turned, and given that the finished pen can be as thin as 0.5mm, providing decent support is rather important.  A knurled knob at one end holds the blank firm as it is turned.

Bush

Different pens have different diameters, both outside to match the components, and inside – the diameter of the brass tube.  Rather than have a mandrel the right diameter for each pen type, bushes are used to fit inside the brass, centering the blank on the mandrel, and the outside of the bush provides a reference for the final thickness the pen needs to be turned down to.  These are a consumable – they do get worn so occasional replacement is necessary.  However, they are only $5 – $8 for a set, so it isn’t too expensive.

Live Centre

Instead of my normal live centre, (or my new Nova one) both of which are too sharp and have too thin a cone end to fully support the end of the mandrel, I found this cheap chinese one, which is hopeless for the job it is designed for, but perfect for pen turning.

Centre matching Mandrel

The short, wide angle and blunt/rounded tip is useless as a live centre, but matches the end of the mandrel surprisingly well.

Sandpaper

Getting the required finish requires sanding (unless you are an expert turner, and even then I imagine they use sandpaper too!), and you always need to work through the sandpaper grits to ensure there are no scratches left to ruin the finish.  This pack provides a convenient storage, and to keep it all in order.

Cyanoacrylic & Accelerator

Other than glueing the tube into the blank, I also use CA glue as a finish, typically with 18-20 coats to produce a very durable finish.  To apply so many layers, the accelerator is necessary.  If one layer is not fully set before the next one is applied the finish is ruined with a milky layer under the surface.  I prefer the aerosol can applicator – a fine, even application.

There is no different between the CA glue here and the Superglue in the small 2g tubes, other than convenience.  A 2g tube will do about a pen, including the finish, give or take.

Acrylic Sanding Pads

Getting a really fine finish requires going to an increasingly fine abrasive, and the acrylic sanding pads are excellent for this, especially when used on acrylic pens, or CA finished ones (you don’t need to CA finish an acrylic pen!)  These pads are coloured based on the grade of abrasive, so it is easy to move from one to the next.  They can be used dry, but they are superior when kept soaked in a bowl, and used wet. This cools the finish, which is important for both types – they are easily destroyed if they get too hot with the friction of sanding, leaving no option but to strip back to bare wood (if a CA finish) and start again, or if an acrylic to drop right back to a rough grade and work you way up again, hopefully the heat affected zone is not too deep.

The pads themselves are also damaged if they get too hot.  A simple rule of thumb is: when used wet, watch out for any dry spots that form which will quickly indicate an area where the temp is rapidly rising.  Watch out for any steam, and feel with your fingers too.  Keep wetting the pads down (dipping them back in the water) – not only will this keep them wet and cool, but also washes off any abrasive particles that have come loose.

The finish these pads do achieve is superb.

Hut Pen Wax

There are other finishes out there, including Hut Wax PPP (Perfect Pen Polish).  These look great straight off the lathe, but I have found them very disappointing with their lack of durability.

Ubeaut Shithot Waxtik

This is a wax by Neil Ellis of Ubeaut, and as you can see I haven’t used it yet (bought it for the name first and foremost!) It got its name from wood turners though, as each when asked how the wax stick was, remarked that it was……., and the name stuck!

Ubeaut was originally going to be called Shithot, but the business licensing organisation cracked it.  At least the product itself, with a typically Aussie approach to naming, made it to the market.

Pen Press

Finally, when it has all been finished, the final assembly can be done.  I used to use a Superjaws for this step, but a dedicated pen press is a much better solution.

Perfect Pen Presentation

Finally, it is imperative that the finished pens are displayed proudly, which leaves only one problem – deciding which one to write with!

Jetstream Conspiracies

It doesn’t take more than a few clicks to be diving deep into websites of paranoia I can tell you.  One that comes up a lot is all about Jetstreams, and Jet trails (or contrails (condensation trails)), with varying, and conflicting reports of mass population control, mass population killoffs, biological weapon dispersal testing, weather altering and control.  The conspiracy theory is that the “government” is playing around with the position of the Jetstream, and using jet trails/contrails to seed clouds, or drop nasty stuff on the uninformed populations below.

What would all these conspiracy ‘experts’ think if they knew there were Multi-Jetstreams!!  And the government knows about them!!

(BTW – from my Navy days – the definition of an Expert:  an Ex is a has-been, and a Spurt is a drip under pressure.  Oh, and if you assume something, you make an ass out of u and me (ass.u.me))

But Multi-Jetstreams are not a myth, nor a conspiracy – they are the latest development in sanding technologies by Festool.  By supplying, and exhausting air through many holes in the sanding pad of a sander (such as a Random Orbital Sander), you have rapid, dust free material removal, a significant decrease in sandpaper clogging which then leads to maximising service like of the sander, the pads, and the abrasives.

High Speed Photos of Sanding with Different Hole Configs

In addition, the airflow helps cool the sanding pad, resulting in the tool, abrasive and work surface being 25% cooler than it would without Multi-Jetstream tech.

(Video below – click to play)

Multi-hole technology

The holes in the sanding pad either provide or remove air depending on their position.  It is curious that there are more holes in the pad than there is in the paper – this is deliberate – air is also supplied below the paper, and all the supply and exhaust holes combine to maximise dust movement and removal as it is produced, reducing heat and clogging.

Supplying air is unusual – pushing dust trapped at the centre towards the outside where it is collected by the multiple extraction holes.  It is backwards compatible with older sandpapers, and new multi-jet paper can be used on old machines – obviously both scenarios do not benefit from the latest technology.

Don’t try what someone suggested on the Festool Owners Group website/forum – drilling extra holes in your current pad.  Sure, it might look more multistream, but there are internal channels leading to these holes in the legitimate pads!

This new technology is now standard in the Festool sander range, and both the ETS sanders and the Rotex will benefit significantly from the improved airflows and dust removal from the sanding surface.

I know they claim a marked improvement in minimising clogging of the abrasives, but I don’t know how it will work in situations that caused me the most clogging – burnishing with oil.  Oh well, you can’t win them all!

T & T Design – Blowfly Sander

In the same YouTube chronicle episode that I showed the Spider Sander, the Blowfly Sander also made an appearance, and again in Episode 010 which was dedicated to the Blowfly. The Blowfly also comes from T & T Design. It is in essence a flap sander that can use a variety of materials. It fits your drill, or drill press.

The Blowfly

The Blowfly

The Blowfly uses the same concept as the Spider in that it utilises inexpensive versions of abrasives – in this case cloth-backed emery paper.  You can substitute a wide range of materials. simply by punching a couple of small holes.  The unit comes with a number of sheets of emery paper, including some (as seen here) that have been cut so it forms fingers for getting into details.

As the material wears, new sandpaper is exposed, and you can also turn the entire piece over to use the back half – getting the most out of your abrasive. As you can see in the piece of abrasive to the side, it only needs a couple of small holes punched to fit it to the Blowfly.

You could use a scourer for more of a polishing result, or let your imagination guide you.  Perhaps some robust cloth dipped in Brasso for polishing brass? Slip a number of abrasive sleeves on each spline?

The Blowfly Core

The Blowfly Core

As you can see in the base, each spline clicks in, making removing and replacing abrasives easy.  The unit (including some emery (both slotted and plain) to get you started) costs $A25.

Q&A with Stan Watson – Technical Director, DMT

I was recently contacted by Stan in response to some articles here that have been referring to DMT Diamond Whetstones, and he kindly offered to field any questions I might have.  Unfortunately I certainly did have some that I was very pleased to be able to put to a real expert in the field, and Stan has agreed to allow me to republish them here. (I have taken the liberty of adjusting the questions and responses a tiny amount (like using the Ex Ex Fine stone!) to fit this format, and open forum).  I found the answers quite fascinating, and they will take a bit to really assimilate them properly into my expanding understanding of sharpening processes.

So to the Q&A with Stan A Watson, Technical Director, Diamond Machining Technology. www.dmtsharp.com

Stu’s Shed:

Sharpening is obviously one of those topics that deserves a decent amount of coverage, which is how diamond stone sharpening became a topic.

In the first instance, I was wondering if I was indeed on the right track when comparing different sharpening media by converting all the different grading systems used to that of the actual abrasive particle size in microns, and if my hypothesis is then correct that you can step from one form to another and back again, so long as you are progressively moving from a larger abrasive to a smaller one?  In saying that, I understand that some abrasives work by breaking down and continuing to abrade as they get smaller so they cover a range of sizes, but the majority are treated as consistent in size from new to exhausted.

Stan A. Watson:

Abrasive particle sizing is at best a huge mix of systems. The single best way of comparing abrasive to abrasive is the micron system which is an actual measure of grain size in absolute terms. The other systems in use today; CAMI / UAMA (Coated Abrasives Manufacturers Institute / Unified Abrasives Manufacturers Institute) FEPA (Federation of European Producers of Abrasives) USS (United States Standard Sieve) JIS (Japanese International Standards) and “grit size” are all arbitrary size designations with no relevance to any true physical dimensional scale. As far as abrasives breaking down during use, you have touched on the vast difference between the action of loose and bonded abrasives and that abrasive which remains solid or which tends to be more friable during use. A loose rolling abrasive sharpening system (lapping, SiC paper and waterstones) tend to produce much different results that a true fixed bonded system such as DMT Diamond Whetstones.

Stu’s Shed:

With that in mind, does the measure of particle size of diamond abrasives fixed to a medium (where only a portion of the particle is actually exposed above the surface) compare with those where the particles are free to move (such as in diamond paste)?  I note from your website that only 1/3 of the diamond is exposed, so is the particle size the site provides the size of the actual diamond, or the size of the exposed portion of the diamond?  (In other words, when I have stated the Ex Fine DMT stone particle size is 9 microns, does it actually perform as one with a particle size of 3 microns)?

Stan A. Watson:

We designate the actual size of the diamond itself so for instance when we state that the Fine / 600 mesh / red / 25 micron grade of diamond, we are actually using a 25 micron size diamond where only about 8 to 9 microns is exposed above the metal bond. That being said, let me state that there is a size range about the mean particle size or a Gaussian distribution of particle sizes which would be from about 23 to 28 micron. But, rest assured that DMT takes advantage of a highly sophisticated system of fluidized bed micronized particle separation to ensure there are no oversized / undersized rogue diamond crystals in each diamond grade.

(Editor’s note: This feature cannot necessarily be said about all diamond stone manufacturers products, this technique ensures a dependable crystal size for DMT stones, but your mileage may vary with other manufacturers, and this can be assessed in part by observing the performance and surface finish obtained when using other manufacturer’s diamond stone products. The problem with a rogue stone in the matrix is it will cause gouge marks in the material being ground that will cause significant amount of additional work with the next stone grade to remove, if that is even possible.)

Stu’s Shed:

By looking at the particle sizes of the 4 sides of the DiaSharp stones I have, there seems to be a large step from the fine to the extra fine stone, and if I was dealing with silicon carbide sandpaper for example, I would use a few more grades in between before jumping to the extra fine particle size.  Is this actually valid, or have I headed off on a bit of a tangent there?  I would expect that DMT wouldn’t put out ‘fine’ and ‘extra fine’ grades without intermediate stones if you couldn’t go from one to the other, but it does seem quite a step.

Stan A. Watson:

The actual step from “Fine” to “Extra Fine” is from a 25 micron to a 9 micron (8-9 micron  to 3 micron exposure) and progresses nicely in the range of micron sizes we offer. You can control the surface finish quite nicely by controlling the applied force during sharpening so as to finish up each step in the progression of sharpening with lighter and lighter strokes. The comparison with diamond to SiC paper is not really an apples to apples comparison as the SiC paper while being a bonded abrasive is friable, looses the particle bond quite easily and could be of either “open coat” or “closed coat” type.

(Editor’s Note: There are two common patterns used when bonding the abrasive to the backing material, called “Open Coat” or “Closed Coat”.

An Open Coat pattern is when there is a lower density of abrasive particles, so the entire particle can dig deeply into the work, facilitating faster material removal, and less likelihood of waste particles clogging the abrasive material.  The particle size in this case – the working size of the particle as it were, is closer to the actual measured size of the particle.

A Closed Coat pattern is when the particles are tightly packed together on the backing material – a denser pattern. With the gap between particles being very small, the abrasive cannot bite in as deeply, resulting in a finer finish (or being realistic about what we are talking about here – a finer scratch pattern), and the effective size of the abrasive particles is much smaller than the actual particles themselves.  These materials tend to need some form of lubrication because of the increased heat buildup.)

Stu’s Shed:

In the article on the Alisam sled, one assumption I have made is the consistency of thickness of the DiaSharp stone (and in particular that the two sides are parallel).  Do you have a listed tolerance for the thickness, or should the stones be mounted in an adjustable holder to ensure the top surface is parallel with the base?  The Alisam sled obviously assumes the sharpening material is parallel with the surface their sled runs on.  I was reluctant to use the diamond stone on my precision granite block, because being double sided, I would expect the diamonds on the underside to cause some damage to the comparatively softer block.

Stan A. Watson:

The DiaSharp product is produced to a parallel,  thickness and flatness tolerance and you should be confident in your ability to step from stone to stone with out having to adjust the iron in the Alisam jig.  Yes the diamond on the bottom of the double sided stones would adversely affect your granite surface plate.

Stu’s Shed:

I am planning on doing a video feature on diamond sharpening (as I have with slow speed grinders, and will for Japanese waterstones and “Scary Sharp”). Do you have any particular advice about the use of these stones that are at the extreme ends of the diamond whetstone scale – the XX Fine and XX Coarse DMT Stones?

Stan A. Watson:

Remember that especially with the performance of the XX Fine there is a break in period and the stone will produce better and better results the more it is used. Also if you are using the XX Coarse to flatten waterstones, do so under running water to flush out the abrasive slurry as quickly as possible.

Stu’s Shed:

Sorry about the long list of questions – writing these articles often raises as many questions as they answer!

Stan A. Watson:

No problem, I am more that happy to correspond with you about anything that I may be able to contribute to.
Best Regard! Stan.

So a big thank you to Stan Watson for not only obliging me with very comprehensive answers to my questions, but also for allowing those responses to be published here.  There will be a video in the near future demonstrating the use of the DMT Diamond Whetstones in action, so keep an eye out for that in Stu’s Shed TV / iTunes.

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