Gear Review: Work Sharp Blade Grinding Attachment

What should I be calling this review? It is actually a review of the optional add-on Blade Grinding Attachment for the Work Sharp Ken Onion Edition Sharpener, which is getting to be quite a mouthful! However although the Blade Grinding Attachment is an add-on accessory for the Ken Onion Edition Sharpener and can’t be used without it, I have titled the review as being a review of the “Work Sharp Blade Grinding Attachment” because for me it is what the attachment brings to the table that is the main feature.

I’ve had my eye on the Work Sharp Ken Onion edition for a long time. For me it wasn’t quite right (though I still think this is excellent as is) until I tried the optional Blade Grinding attachment.

For my needs it is the Blade Grinding Attachment that transforms the Ken Onion Edition Sharpener into a real workhorse sharpening system.

The Blade Grinding Attachment effectively adds a mini bench belt grinder to the Work Sharp, and this was the clincher for me. I’ve been using a 1″ belt grinder with an angle setting guide I made and added to it myself for 99% of my sharpening. Now, thanks to Work Sharp I’ve got a much more compact and specifically knife edge focused tool.

This fantastic sharpener is now being used to create the Tactical Reviews ‘WORK SHARP Sharp’ standard for all my knife testing.

Join me in this detailed look at the optional add-on Blade Grinding Attachment for the Work Sharp Ken Onion Edition Sharpener.

Review Videos

Starting with a short format sixty second review:

Onto a full video review covering many more details:

A little more Background:
Before diving in to the image galleries, in effect there are two reviews combined here. The Work Sharp Ken Onion Edition Sharpener, and the separate Blade Grinding Attachment for this sharpener. This combination is also sold as a kit version called the Work Sharp Elite Knife Sharpening Solution.

A few more details:

What’s in the box? – Ken Onion Edition Sharpener:
This is the foundation sharpener, which is complete in itself.

A good look round the Ken Onion Edition Sharpener – Things to look out for here are:
Using an in-line transformer makes for a very tidy setup, and of course it will have the mains plug suitable for your country. Though it looks like a single machine, the sharpener is a motor/control unit, and a belt sharpening head that fits onto the motor assembly (this is important later when it comes to the blade grinding attachment).
The Ken Onion Edition Sharpener head has a pair of angle guides plus an edge guide to support the blade. To control the speed of the belt, the motor unit has a trigger with rotating maximum speed dial. The trigger also has a locking button so you can set it running and not need to hold the trigger switch, leaving you both hands free.
Sharpening angle is set using a dial adjuster with clearly marked angles from 15 to 30 degrees. The last image in the gallery with the spring showing is the belt tensioning roller.

What’s in the box? – Blade Grinding Attachment:
As well as the main sharpener, the Blade Grinding Attachment also has an unsupported, or ‘slack’ belt, so will create a convex edge. In the box are the attachment and a set of belts for it, as these are a different size/length compared to the main sharpener’s belts.

A good look round the Blade Grinding Attachment – Things to look out for here are:
One of the belt rollers is the motor spindle itself, so on its own it might appear that one belt roller is missing (but isn’t). The Blade Grinding Attachment has three rollers; one tensioning roller, and an angle adjustable set of twin rollers that give you the edge angle you want. A shelf at the front of the Blade Grinding Attachment gives you the zeroing position of the blade angle relative to the adjustable angle section of the belt. The set of twin rollers is moved to the desired angle and the locking screw on the back tightened to maintain this setting. There are two positions for one of the twin rollers that allow you to effectively change how ‘slack’ the belt is. The knob on the tensioner provides tracking adjustments for the different belts. There is even a small support shelf at the rear of the Blade Grinding Attachment for using as a mini belt grinder. Fitting to the motor is via a bayonet style of locking ring.

What it is like to use?
In this gallery, the first thing I am doing is taking off and discarding the sharpening head for the Ken Onion Edition Sharpener to leave just the motor assembly (no offense to the Ken Onion Edition). Then on goes the Blade Grinding Attachment. Now you can see how the motor spindle (which has a left-hand screw belt retainer fitted into it) then completes the belt roller path.
The tensioning roller has a finger tab for you to push on and it rotates and locks into a retracted position. Like this the belt pops on and off easily, and with the new belt in place, a quarter turn on the finger tab and the tensioner unlocks and grabs the belt.

Although the Blade Grinding Attachment has clamping points, I’ve been using the sharpener sitting under its own weight, and it hasn’t moved or needed to be secured.

The process of using the angled section of the belt, is to first lay the blade on the reference surface at zero degrees, then move up and to the belt. This sequence is showing the process on one side, then the other, and then going to a finer belt and repeating. The last photos in the gallery has an orange item on the right, which is an LED light used to help show the burr that has been raised on the edge.
In this gallery the two rollers that set the angle for the belt are shown in their widest spacing, however, since these images were taken I have changed to the narrower spacing as I prefer the slightly firmer belt tension this creates between the rollers.

Powered sharpeners give you such a massive time saving over manual sharpeners, but it is also possible to make mistakes faster too.

Here I have take on an edge bevel re-profile from a 70 degree inclusive angle to 35 degrees inclusive. The primary grind angle on this blade is quite wide, so as the edge bevel angle was halved, the edge bevel width has increased significantly. In fact the entire edge bezel does not fit in the magnified view.
This re-profiled edge was done using a very light pressure onto the 120 grit belt, followed by a strop using a metal polishing compound. The result was nicely hair popping.

Both the Work Sharp Ken Onion standard sharpening head and the Blade Grinding Attachment use a ‘unsupported belt’. There is no platen behind the section of belt used for sharpening. This is also termed a ‘slack belt’. A consequence of this is that the edge created by the Work Sharp is convexed. You can vary how much the edge is convexed in a couple of ways. With the Blade Grinding Attachment, the rollers that set the angle of the belt can be positioned closer (less convexed edge) or wider apart (more convexed edge). As the belt is ‘slack’ you can also increase pressure onto the belt, which will deflect it more and produce an edge with more pronounced convexing.
All of this allows you to play around with settings and pressure to find the edge bevel shape you prefer; always slightly convexed, but you can decide how much.

I am now going to back to that point about time saving with a powered sharpener; you will either save a lot of time making a knife very sharp, or ruin it in double quick time. No sharpening system is fool-proof. Sharpening, as a process, relies on removing metal and forming a fine cutting edge. Just like sharpening a pencil, you can over sharpen and use the pencil up much faster than needed. A powered pencil sharpener can eat up the entire pencil in no time.

Sharpening is a skill you need to learn, whatever system you use. Work Sharp, with the Ken Onion Edition, or this extra enhancement of the Blade Grinding Attachment give you an excellent tool, which you will get more and more out of as you learn to work with it.

With a good powered system, and the Work Sharp is excellent, you can concentrate on the skill and control of positioning the blade, without the repeated effort of grinding the metal away yourself. The powered movement of the abrasive allows you to finesse your technique.

Tactical Reviews new standard in sharpness is now ‘WORK SHARP Sharp’ thanks to the Ken Onion Edition Sharpener with Blade Grinding Attachment.

Review Summary

The views expressed in this summary table are from the point of view of the reviewer’s personal use. I am not a member of the armed forces and cannot comment on its use beyond that covered in the review.

Something that might be a ‘pro’ for one user can be a ‘con’ for another, so the comments are categorised based on my requirements. You should consider all points and if they could be beneficial to you.

What doesn’t work so well for me

Very easy to misshape the blade tip (requires good technique to avoid).
The vertical belt section is also not supported and flexes.

Things I like

Complete control of belt speed.
Quick and easy belt changes.
Long duty cycle (rated for 1 hour continuous running).
Allows for varying amount of edge convexing.
Angle of belt set by movable roller assembly.
Very compact for a high quality mini belt grinder.
Super fast sharpening and re-profiling.
Solid build quality.
Very quickly get your edges ‘WORK SHARP Sharp’.

Discussing the Review:
Something new – will it work? A Tactical Reviews Subreddit.
TacticalReviewsChat on Reddit
Please visit there and start/join the conversation.

Gear Review: DMT Aligner ProKit and DuoSharp 10″ Bench Stone

 photo 00-DMT-featureV2-P1180049.jpg

It is possible to put a great edge onto a knife with very basic equipment and a lot of time. However, with the ever harder and more abrasion resistant steels, diamond stones make it much easier and faster to achieve that edge. DMT are one of the best, if not the best, makers of diamond sharpening stones. If you have checked my ‘Recommended’ page you will have seen that DMT was actually already my favourite diamond sharpener brand, with a pair of DiaFolds (Coarse/Extra Coarse and Fine/Extra Fine) always with me for field maintenance.

In this review I’m looking at two very different sharpeners, a large bench stone (Duo Sharp 10″ Bench Stone) and a guided precision sharpening system (Aligner ProKit).

 photo 00 DMT both P1170999.jpg

“Getting your EDGE back”:

There are so many variations in knife design, size and purpose, and I shall continue to try and review as many as I can, but the one thing that they all have in common is a cutting edge, and it is that edge which makes a knife into a tool. When you buy a knife, the factory put an edge on the blade, but this can vary considerably in quality even from good manufacturers. Relying on the factory edge is like buying a car and only driving it as far as the original tank of fuel will take you. You can transform the performance of a knife, so it is worth investing in quality sharpening equipment.

Actually this section title uses the name of a sharpening service I offer to neighbours (100% going to charity), and is absolutely appropriate for anyone who wants to have the best performance from their cutting tools.

I’ve used just about every method of sharpening, both manual methods and powered. These range from the humble carborundum bench-stone to high-end guided sharpening systems, as well as various wet/dry grinders and belt sanders. Manual sharpening does take longer, but gives you greater control and removes less metal. Where Diamond sharpeners really stand out is the speed they cut, and a quality diamond stone can cut 6-10 times faster than other stones. That is a lot fewer strokes you need to make.

There are many diamond stones to choose from with very different prices. DMT claim the flattest sharpening surfaces with the highest quality of diamond particle and density of coating. I can’t examine this to confirm or deny their claim, but what I can say is that where other diamond stones have let me down and worn out quickly, the DMT stones I have, have worked very very hard and are still going strong.

A few more details of the Aligner ProKit:

The Aligner ProKit comes in a storage/carry case.
 photo 01 DMT Aligner Box P1180054.jpg

For this review DMT have also included the Extra-Extra-Fine stone (pink colour) so this is not normally in the ProKit pack. What is included are the three grits Coarse, Fine and Extra Fine, the stone holder/guide-rod, the Aligner adjustable clamp and guide, a tapered serration sharpening diamond coated rod plus the instructions.
 photo 02 DMT Aligner Box open P1180056.jpg

Laying everything out, this is what is in the box (remember the pink stone is not part of the ProKit).
 photo 03 DMT Aligner Box contents P1180061.jpg

As it can’t be fitted into the stone holder, the tapered rod has its own guide rod which screws into the widest end.
 photo 04 DMT Aligner serration rod thread P1180063.jpg

I don’t have a microscope to really go in ultra-close to the different grit stones, but this series of images at the same scale give an indication of the different grits.
First up is the Extra-Extra-Fine where the surface appears almost as if there were no particles in it.
 photo 05 DMT Aligner extra fine P1180066.jpg

Moving up to Extra-Fine and the surface is starting to take on a textured appearance.
 photo 06 DMT Aligner fine P1180067.jpg

With Fine you can see the grainy surface.
 photo 07 DMT Aligner medium P1180068.jpg

Finally with Coarse there is a distinct texture to the surface of the stone.
 photo 08 DMT Aligner coarse P1180069.jpg

Each of the different grit stones are fitted into the holder for use.
 photo 09 DMT Aligner holder P1180071.jpg

The stone is pressed into the pocket in the holder.
 photo 10 DMT Aligner holder P1180073.jpg

Then the lock at the end of the holder is turned to hold the stone securely in place.
 photo 11 DMT Aligner holder P1180074.jpg

A closer look at the rotating lock. Initially the fit of the stones into the holder is snug enough to not need the lock, but as you use it more they loosen up slightly and you do need to use the lock.
 photo 12 DMT Aligner holder lock P1180075.jpg

Being a portable kit, the stone holder has a folding guide rod. Here it is folded over the stone.
 photo 13 DMT Aligner holder folded rod P1180078.jpg

The rod hinges round and locks into place in the open position.
 photo 14 DMT Aligner holder rod hinge P1180079.jpg

Then we have the crucial part of a guided system, the guide itself. This is a clamp which fits onto the blade spine and has adjustable guide rings for the guide rods to run in.
 photo 15 DMT Aligner clamp P1180082.jpg

Looking in close at the clamp jaws. There is a brass screw for adjusting the width of the jaws.
 photo 16 DMT Aligner clamp jaws P1180084.jpg

With the jaws adjusted to the right size, a locking screw is used to tighten the jaws onto the blade.
 photo 17 DMT Aligner clamp lock screw P1180085.jpg

Each of the two guides have a number of positions they can be set to. Each of these positions has a groove moulded into the guide arm.
 photo 18 DMT Aligner clamp guide adjuster P1180087.jpg

Here we have the clamp fitted onto a blade and the guides set to position 3.
 photo 19 DMT Aligner clamp fitted P1180095.jpg

A few more details of the DuoSharp Bench Stone:

The box was shown earlier along with the Aligner ProKit. Inside the box you get the DuoSharp, a sharpening guide (showing other DMT products) and a set of rubber feet.
 photo 01 DMT Benchstone contents P1180008.jpg

There are eight feet which need to be fitted to the eight pegs (two in each corner).
 photo 02 DMT Benchstone feet P1180012.jpg

While the bench stone is upside-down one of its stand-out features can be seen – a handle. This is part of the DuoBase design.
 photo 03 DMT Benchstone handle P1180014.jpg

The handle means that you can take the stone to the blade instead of the blade to the stone. For larger blades this is ideal and makes the DMT benchstone pretty unique. Later on I show an example of exactly this with a ham knife.
 photo 04 DMT Benchstone handle P1180017.jpg

The Diamond stone slab is double-sided, so for the other grit you need to flip it over. It is held onto the base with two plastic clamps. Turning the base over you can see the two tabs that click into place. (you can also see the positions these can be put for the smaller 8″ stone.)
 photo 05 DMT Benchstone clamp P1180021.jpg

Simply pinch these together to release the stone clamp.
 photo 06 DMT Benchstone clamp release P1180023.jpg

You only need to remove one of the clamps to allow the stone to come free.
 photo 07 DMT Benchstone off P1180024.jpg

Fitting in with the colour coding across the DMT range the Red dot represents the Fine grit. The smaller blue dot shows what grit the other side of the stone has – in this case Blue/Coarse.
 photo 08 DMT Benchstone grit indicator P1180028.jpg

The DuoSharp 10″ benchstone has an ‘interrupted’ surface which helps clear the filings produced during use. There are a couple of pin marks into the plastic which probably relate to location pins used during the moulding of the plastic part.
 photo 10 DMT Benchstone holes P1180033.jpg

You can see how the diamond surface has been moulded into a plastic base-plate. One end has the elongated tab, only part of which fits under the stone clamp.
 photo 11 DMT Benchstone corner P1180036.jpg

The other end has a smaller tab for the stone clamp to hold.
 photo 12 DMT Benchstone other end P1180037.jpg

Flipping the stone over you can see the Blue grit indicator spot, this time with the smaller Red dot for the other side’s grit.
 photo 13 DMT Benchstone other grit P1180041.jpg

Fixing the stone back onto the base, first slide the tab under one stone clamp.
 photo 14 DMT Benchstone fitting P1180044.jpg

Then fit the second stone clamp.
 photo 15 DMT Benchstone fitting P1180047.jpg

Press the clamp down until it clicks into place.
 photo 16 DMT Benchstone fitting P1180049.jpg

For an idea of scale, here is the stone next to a Fällkniven F1. At 10″, this is a good sized stone.
 photo 17 DMT Benchstone size P1180050.jpg

What are they like to use?

Firstly, the Aligner fully packed in its box is not only compact, but is also light weight. This makes it a great kit to take with you on trips, to keep in the car, or to use to sharpen friends/relatives knives. With DMT diamond stones being used dry you also don’t need to carry any oils or lubricants, so overall it is very convenient.

Clamp based sharpening systems are limited by the capacity of the clamp. The Aligner’s clamp has a 6.5mm capacity if the adjustment screw is fully removed and reinserted one half turn. I’d prefer more than half a turn, so I think a 6mm blade thickness is a more realistic maximum.

It is best to have an ‘approach’ to keep your results consistent. In this case what I’m referring to is the clamp position. Moving this along the blade will change the angle the stone runs on the edge. So far my approach has been to fit the clamp in the centre of the cutting edge of the blade on every blade I sharpen. Working in this way, in future you will put the clamp into the same position for subsequent sharpening sessions.

As with this type of guided sharpening, once the clamp is fitted to the blade spine and locked on, sliding the guide rod into the guide ring you can now move the stone across the knife edge at a consistent angle.

If you are not used to working with this can be a little awkward. The instructions say to hold the knife handle in one hand and the stone holder in the other; personally I find it easier to hold the clamp in my left hand (I’m right handed) with the blade sitting on my hand. The feel is the same for both sides of the blade. If you have to hold the knife handle it means swapping round an moving the stone with your non-handed hand as well.
 photo 20 DMT Aligner sharpening P1180096.jpg

For narrow blades you should check for clearance (keeping the stone from wearing into the clamp). In this case there is plenty of room, but the blade is not narrow.
 photo 21 DMT Aligner sharpening P1180097.jpg

To select the right angle you can use the ‘Sharpie’ method (using a marker pen to blacken the edge bevel and check where the stone is cutting) and if necessary adjust the position of the guide rings. If you are using different settings for different blades, you will want to keep a note of the positions used for each blade to allow you to sharpen it properly next time without changing the bevel angle.
 photo 22 DMT Aligner sharpening P1180103.jpg

Once you are done, I find it best to leave the clamp on the blade when you test the edge in case you need to work on the edge a little more.
 photo 23 DMT Aligner done P1180105.jpg

Overall the Aligner is light and efficient, and the DMT diamond stones cut very well.

Update 20 Jan 2017
Following some discussions on the clamp being liable to flex as it is plastic, I wanted to show more clearly how I use the Aligner and similar guided sharpeners. In the instructions for the Aligner it show the stone being held under the knife and the knife being moved over the stone in a similar way to using a bench stone. This means you are holding the knife by its handle and pressing down onto the stone. Like this there is maximum room for flexing. However I have always used this type of guide differently.

I hold the clamp and allow the handle to rest onto my wrist for this side of the blade.
 photo 32 Aligner holding P1250263.jpg

And for the other side I again hold the clamp and support the handle (or blade depending on the blade length) with my third and fourth finger. This way round the blade also sits onto the pad of my thumb.
 photo 33 Aligner holding P1250265.jpg

In this way it is possible to support where the clamp holds onto the blade while you bring the stone to the blade.
 photo 30 Aligner holding and using P1250260.jpg

And the other way. Hopefully this show clearly why I haven’t had any actual issue with flexing from the plastic clamp.
 photo 31 Aligner holding and using P1250258.jpg

End of Update 20 Jan 2017

Now we move onto the DuoSharp Bench stone and the technique requiring most user skill. However due to its wide flat surface and diamond cutting efficiency it certainly seems to make sharpening this way much easier than on the carborundum stones I learnt on.
 photo 18 DMT Benchstone kitchen P1220149.jpg

The kitchen knives being sharpened are slightly magnetised due to being stored on a magnetic rack. The filings stand themselves up like this due to being magnetic themselves. A wipe over with a damp rag clears these off nicely.
 photo 19 DMT Benchstone kitchen filings P1220161.jpg

A few of the knives this stone breezed through.
 photo 20 DMT Benchstone kitchen knives P1220169.jpg

Now onto something a little more challenging, a 16″ ham knife. Ham knives are super flexible and thin, so are not easy to work onto a stone with.
 photo 21 DMT Benchstone ham knife P1230617.jpg

This blade had seen some abuse in the past and the edge was a bit wavy. I wanted to tidy it up and put together a very simple jig to keep the blade straight. A couple of stop-screws on a wooden base and some masking tape to keep it in place. To the right you can see an angle guide I setup for reference to help me stay on track.
 photo 22 DMT Benchstone ham knife jig P1230623.jpg

Using the handle on the back of the base I then used the bench stone hand-held. Working on the long and flexible blade in this way was so much easier and resulted in a corrected and hair-splitting edge (after a final strop).

The only real limitation with a large flat bench stone like this is with the recurve section of some blades. Those concave recurve sections just won’t get to touch the diamonds, but that is always the difficulty of a recurve blade.

Being able to hand hold the DuoSharp bench stone was an unexpected benefit of the DMT design and makes it much more versatile.

Review Summary

The views expressed in this summary table are from the point of view of the reviewer’s personal use. I am not a member of the armed forces and cannot comment on its use beyond a cutting tool or field/hunting knife.

Something that might be a ‘pro’ for one user can be a ‘con’ for another, so the comments are categorised based on my requirements. You should consider all points and if they could be beneficial to you.

_______________________________________________ _______________________________________________
Things I like What doesn’t work so well for me
_______________________________________________ _______________________________________________
Aligner package is lightweight for easy transport. Aligner guide clamp will only fit blades up to 6-6.5mm thick.
Aligner ensures you maintain a consistent angle. Aligner – One side of the blade is more awkward to work on than the other.
Aligner – Easy swapping of grits. Aligner – Clamp needs to be fitted tightly and can flex if pressing too hard.
Bench Stone – Large flat surface. Bench Stone – Large surface prevents recurve blades being sharpened.
Bench Stone – Handle included to allow hand-held use. Bench Stone – Rubber feet can fall off.
Bench Stone – Easily identifiable grits.
DMT stones can be used dry.
DMT diamond surface cuts very well.

 photo 00-DMT-featureV2-P1180049.jpg


Discussing the Review:

Please feel free to add comments to the review, but the ideal place to freely discuss these reviews is on a forum. If you started reading the shorter forum version of the review, but followed the link this full exclusive review, please return to that forum to discuss the review there.
If you read the review entirely on Tactical Reviews, please consider one of the following to join in any discussion.

EdgeMatters – Sponsored Reviews (UK based Forum for Knife Makers and Collectors)

BladeForums – Knife Reviews (US based Forum for Knife Discussion)

CandlePowerForums – Knife Reviews Section (Largest and Friendliest Flashlight Community Forum)