Work Sharp 3000/diamond discs/establishing chisel surfaces...

[ian maybury]

Part update, and part invitation for comment. Been working my fingers to the bone (almost literally )setting up a bunch of Japanese Matsumura white steel bench chisels. Dead pleased (but not experienced with waterstones) with the modified Veritas Mk 2 guide (previous post) and Shapton 1,000, 2,000, 5,000 and 12,000 combo. The 2,000 is probably not strictly necessary, but i'm using it since I have it and it lightens the load for the 5000 which doesn't seem to cut all that aggressively.

Getting the surfaces established has proven to be the toughest part of the job - all of the chisels so far have been high on the back a little behind the edge. I did a couple using a 120 Shapton which was slow, the surfaces rough (needing a lot of work on the 1000 to get rid of the scratches), and it didn't give the same feedback as the other stones. Switching to the WorkSharp 3000 (working from the top with the Mk2 honing guide and the accessory platform - the latter levelled accurately to the disc surface so that the bevel angle won't change upon moving to the waterstones) for backs and bevels has worked well. (but a wrong touch when doing the backs could do a lot of harm)

120 and 400grit discs deliver a nice surface that the waterstones can bring up to a polish with two passes a la Charlesworth on each. It's been important to form an accurate/dead flat bevel, as even tiny irregularities take a lot of cutting out on the waterstones. The cylindrical roller on the Mk 2 makes achieving this easy.

Care is needed on the Worksharp - even at its low speed it'd be easy to very quickly overheat the extremity of the edge. I guess the real deal would be a water cooled WorkSharp - but even cutting in bursts of only a couple of seconds and cooling in between it's quite fast. I was surprised to find it was doing the backs flat enough to finish them on the waterstones.

A longer lasting disc would be nice. Has anybody got more experience with diamond lapidary discs since the posts a couple of years ago? Thinking of the cheap Chinese ones on E Bay - do they work well, and is the grading and quality consistent?

ian

[David Barnett]

A longer lasting disc would be nice. Has anybody got more experience with diamond lapidary discs since the posts a couple of years ago? Thinking of the cheap Chinese ones on E Bay - do they work well, and is the grading and quality consistent?

They do indeed work well and are amazingly inexpensive. I buy the PSA 'toppers' and mount them onto master laps. Although I buy and use mine for gem faceting, when I first get the coarser discs I often break them in on tools before they settle in a bit and are acceptable for faceting where I need them to cut more evenly with fewer deep scratches from outlier crystals. Overall, they're as consistent and long-lasting as the domestically-made more expensive steel mounted lapping discs and for the price simply can't be beat.

[Prashun Patel]

There are a couple threads on this topic.

I use those discs on my Worksharp for the same thing you do. They work wonderfully.

I have a 120, 220, and 500 from two different manufacturers and they are fine.

I even have a '3000' grit polishing disc. I don't like this one so much. It gunks up too quickly. However I do find that a very quick pass on the 3000 makes my manual stone honing go extremely quickly.

[David Weaver]

Use care on those japanese chisels if you're going to power-do the back of the chisels. At the cost of matsumuras (which are fairly inexpensive for japanese chisels), I guess it's not a big deal, but you don't want to blow through too much of the ura on the back - it's just bad form and you can make some ugly looking chisel backs that way. I'd do them by hand with a diamond hone and with care - and most importantly don't let half of the chisel hang off of a stone and half on - it's either only the very tip on the stone or all of it, or the edge of any stone or worksharp, etc, will blow right through the lands in the middle of the chisel and make a VERY ugly step.

[ian maybury]

Thanks guys. I'll order a few discs Prashun and see how i get on - they were so cheap that it made me nervous. Think it was your write up on their use I saw a couple of years ago. (?)

The backs seem to be doing OK David, or at least so far as i can tell - but see the sample not very clear photos taken just now below. The backs are uniformly finished over their full length even though the pic due to shadow doesn't show it. The bevels (while they likewise don't look it here - they do in normal light) are finished on the 12,000 grit stone and polished the same as the backs. The backs were done (after first making sure there was enough clearance for the shank) by dropping the entire back face of the chisel flat on the WS's disc, with the rear down a shade to protect against accidentally putting on a back bevel. Also with the cutting edge pointing downstream re. rotation. Then lifting off again after a couple of seconds to avoid heating.

All of the backs have been slightly but to my mind unexpectedly bulged so far - with the (low) peak 15 - 20mm back from the edge. No twisting, and nothing that wasn't removed in a few minutes on the WS 3000 or the 120 stone though. There's some variability in the width of the flat land between the edge and the nose of the hollow as they come. (ura?) It sounds from reading that tapping out might have saved some material, but it sounds like it may be a bit risky on especially smaller chisels.

The flattened area creeps slowly forward to the cutting edge cut by cut on the WS's disc - so it's very controllable. A slip could do harm very quickly though. It's also generating a very flat and uniformly ground surface that pretty much immediately cuts all over on the 1000 waterstone - the possbility that it might not was a concern before trying it. The narrow chisels need extra care, in that it all happens faster.

Persisting with the 1000 grit until both faces definitely extend right to the edge is absolutely key - it'd be very easy to leave a bit of a chamfer or bevel intact on the edge. Having first finished the back the chisels were then loaded into the honing guide and the bevel formed on the WS. (2 sec bursts again, cooled in between in water) The chisel bevel (without removing it from the honing guide) was then finished to 12,000 on the waterstones in the same sequence as the back.

So far it's about putting a functional working edge on, but i guess there's a whole other body of technique to be researched and experimented with beyond this point.

I should say that while I've not been posting that I've been reading the posts here and doing some ad hoc sharpening over the past couple of years - so my thanks to everybody. It's so much easier with guidance...

ian

chisel backs 23-7-14.jpg chisel bevels 23-7-14.jpg

[David Weaver]

Looks good, coplanar is fine. I've had a couple of the matsumura branded chisels and they are accurately ground - flat like that. Some blacksmiths make their chisels bellied such that you need to flatten only the first part of the edge (like a half inch). Since those are flat, doing the whole back is a good method.

Either way is fine as a way of making the chisels, bellied or flat, though you don't want to attempt to flatten the whole back of a bellied chisel.

If they chip at all, increase their angle a little. If you get to the point that you're getting them to fail by what looks like wear, then they will last next to forever. If the angle is too acute and they chip substantially, then you'll find they aren't very convenient to keep in shape.

[ian maybury]

Thanks David, that's reassuring. Have to say that while the chisels are still to be really tested that I love the feel of the steel - it's tough yet cuts so cleanly on a stone, and has none of the tendency to develop a hairy great wire edge that you get with mainstream cheap chisels. It sounds from previous posts that the WS 3000 leather honing and felt buffing wheels work very well, so that's next on the list....

Some info for broader consumption on sourcing WS 3000 consumables.

Prashun and others have already mentioned that 150mm diamond coated lapidary discs work well for chisel bevel forming and (careful) back flattening, and come very cheaply off EBay - I've just ordered some in 150 and 500 grits to try from a supplier in Hong Kong.

Branded WS accessories are horribly expensive here and in the UK as a result of heavy marking up of what I suppose is a speciality product, but it turns out that the 150mm x 13mm thick x 12mm bore felt buffing/polishing wheels are also a widely available commodity accessory used elsewhere. They likewise are available on EBay for a small fraction of the OEM cost - and while not yet received or tested look to be identical. (1/5 of the cost of the branded item in my case)

I have the WS leather stropping disc, but it probably wouldn't be too hard to DIY or maybe improve one if needed by adding the appropriate piece of leather to one of the WS glass discs. Wonder how some bonded on MDF or similar might do for this use?

ian

[David Weaver]

You may like the MDF itself as a substrate. Especially once its had a chance to load a little.

[ian maybury]

Ta David, you're up early...

This is just an idle floating of the topic, but it turns out there's a sceptics view on the usefulness of stropping too. See this page by Brent Beach: http://www3.telus.net/BrentBeach/Sharpen/Stropping.html He argues the science says that most compounds contain much coarser abrasive particles than the finest stones/papers, and that by scratching surfaces they do more harm than good. Also that properly graded e.g. 0.5 micron compounds have such minimal cutting ability that they can only be effective on very narrow micro bevels. That the commonly reported benefit of honing is mostly the result of shortcomings in the honing process.

I have to say that some of the very heavy duty (leaning on the blade) stropping techniques demonstrated in one or two videos make me nervous - it's hard not to suspect that it may do a number on a finely honed edge. They may on the other hand shift enough metal to be effective in improving a not so finely honed example. Or perhaps in the case of the good compounds the grits break down so that the finish is much finer than the grit grading might suggest? Might it also be the case that a honing guide doesn't necessarily deliver absolute precision, and that we perhaps form a tiny micro bevel as a result of the roller lifting up on sharpening debris, and our applying pressure right out at the tip of the tool?

Guess what i'm getting at is that if the science says one thing, and genuine observations another that some means has to be found to square the circle if we're to understand what's really going on.

ian

[David Weaver]

Frankly, brent beach doesn't know enough about stropping to really know what he's talking about - the first clue is that he associates stropping only with using compounds, and doesn't describe why people would strop to begin with (I'd imagine he's unfamiliar with natural stones). He also seems to be unaware that there are powders and compounds widely available down to .05 micron (that's not a misprint). I have no idea what beach would do if he were faced with an incannel gouge, or any gouge for that matter. he might find strops very useful if that were the case.

At any rate, i don't generally use those compounds because they're not necessary, and also for the reason you mention - I'd rather do the heavy work with a stone and preserve geometry and control it so that the next wire edge is raised easily when I sharpen again. When I strop, it is with clean bare leather.

Stropping itself is another thing that you will get a good grasp of only with experience, to improve an edge with it, and to figure out the things it works with well. It is my opinion that it offers little on the very hardest of steels, but on vintage steels, it provides quite a gain. The same is true with razors. The super ultra hard razors do respond a little bit to a strop, but not so well as one that is medium hard.

All of that said, what brent doesn't give much of a nod toward is how sharpening actually fits in a work flow, with various shapes of tools and in the context of actually doing work and letting results dictate technique. I can't imagine having to stop and use his process in the middle of a session preparing a large rough panel. His pointers are useful to show that some of the popular compounds do have large particles in them, but the suggestion that graded chrome ox is too slow is only worthwhile if you're actually trying to use it to cut steel at a significant rate - which isn't its use, either. (it's a lovely thing for razors, if the razor is brought to it sharp already).

At any rate, my suggestion would always be to look at what the folks doing what you're doing ...do. If you're preparing boards from rough, find out what joiners and cabinetmakers do/did to sharpen. If you're carving, find out what carvers do. If you're sharpening and stropping a razor, find old barbering texts. The answers will often be different when in the context of the work than they are outside of it by someone trying to parameterize everything.

Anyway, the reason you might like MDF on the WS is that it's a bit harder than leather, but as it loads it becomes slick and it doesn't threaten geometry. I've got a 6" leather wheel attached to the disc on one of those junky combination belt/disc sanders, and while it works, it's no quicker for me than stones and because of the power aspect, it has an appetite for disregarding the geometry you've carefully set up on an edge. Once geometry is right, you only hone out wear, except in extreme cases where you want something like an ultra thin low-angle paring chisel or something. Parsimony in wear and in removal of steel, and preservation of geometry, while doing great amounts of work becomes infinitely more satisfying than mass removal methods.

[ian maybury]

I'll give the MDF a run David - and try some hard leather as well. What you say about taking care to preserve geometry is where my gut tends to lead me too. Plus it's got to be a lot about removing even a miniature wire edge. The prospect of having a convenient means of freshening up and edge to hand without having to go back to a multi step honing process every time is very attractive...

[Cody Kemble]

The glass disks are around 3/8" thick. Has anyone found a decent souce of 3/8" MDF in smaller quantities? I built my own platform to sharpen with my Mk2 on a WS3000 and didn't make it adjustable.

[David Weaver]

You can hand plane MDF if it comes to that. Just plan to do a lot of sharpening and take thick shavings, and then sand it as you get close to finish thickness, leaving the factory side that's left face up.

[ian maybury]

A quick look after posting this morning threw up this untried EBay UK source of low cost 3mm (1/8in) MDF discs for about $4.50 for 3 no. Cody: http://cgi.ebay.co.uk/ws/eBayISAPI.d...E:L:OC:GB:3160 Seemed easier than setting up a circle cutter. Not sure what the material will be like, but it seemed worth a try. I've also got some double sided adhesive film to stick them down to a WS glass disc.

There doesn't seem to be a similar option coming up on EBay.com, but the cost of local shipping for my order was very moderate so maybe it'd be worth ordering from the US. Failing that maybe there's somebody about with a CNC laser set up that would run some for you?

I've seen mention before of treating MDF with Danish oil before using it as a lap David - it may be one way of toughening up the surface a bit. Not sure how it might behave? Most when lapping in effect introduce a small angle. Wonder if it makes sense to do so, or to lap flat?

[ian maybury]

Hi guys. Just to table a point/thinking out loud. It seems pretty clear that there's a considerable overlap between stropping and honing.

Waterstones for example go to 12,000 grit (1 micron) or finer, and this is finer than the coarser particles in many of the stropping compounds in common use. Even the highly regarded Veritas green of nominally 0.5 micron seemingly contains particles multiples coarser than 1 micron.

The result delivered then seems to be significantly complicated by the fact that abrasive particles may or may not break down, and may cut more or less deeply for a given size depending on the material and nature of the matrix they are embedded in or spread over - meaning that apparently coarser/finer material may not behave that way. There probably isn't much option but to experiment or at least be led by personal or second hand experience.

What does seem pretty clear is that guy like Paul Sellers that suggests a heavy duty version of stropping (leaning heavily on the tool) after a 1000grit abrasive is relying on it to remove a fair amount of metal. This isn't necessarily what's needed with an edge that's been carefully worked down to 12,000 grit or so on waterstones. In this latter case it's probably more about removing micro defects from am already established edge, and as David has suggested using a hardish strop that's less likely to round over (dub?) an edge and much less pressure.

Looking a videos by the razor guys there seems to be scope for an alternative approach to finishing off an edge by honing on the finer grits of waterstone - by for example reducing to very low pressure at the end, and for only a very few strokes.

One major attraction of stropping seems to be it's convenience as a quickie 'go to' means of regular refreshing an edge - not so easy on a waterstone if using a honing guide, and if the bevel is also to be touched up… (it requires in the case of a single bevel getting back to exactly the same angle)

ian