ian maybury
07-18-2014, 2:55 PM
Hi guys. :) Free hand sharpeners please look the other way.
A Veritas Mk 2 honing guide bought a few years ago didn't work with my Japanese chisels (photo 1) - i've been getting by with the commonly used Eclipse type.
It wouldn't reliably clamp/hold them - in fact it would hardly hold them at all. The slightly sloped backs worsened the situation, but it wasn't getting much of a grip on flat/parallel backed Western chisels either. A disaster - it's one thing that a honing guide must do well. Others have run into this issue judging by web comments.
Thinking it'd be a pity to dump it given all the nice features and the cost (and having dug it out again i was eyeing the microbevel adjustment) the question became how to sort it out.
The core problem (found in my example) is that the working surface of both clamps (aluminium die castings) is black powder coated. It's a very durable finish, but slippery as hell. The indentations in the surfaces look like they could both have been designed to be fitted with gripping pads which never made it into production…...
This creates the possibility of a secondary problem - the clamp bar with the studs in will likely bend if overtightened in an effort to get enough grip - even heavy finger tightening visibly bows it. (both sides must anyway be evenly tightened on a flat backed chisel or plane blade so that it makes contact acros the width)
Cutting back the working faces of both jaws on a fairly coarse diamond plate to create a flat bare aluminium surfaces results in a fix - a clamp that grips well. (see photo 2) Night and day compared to the original - and able to hold very narrow chisels too.
While there's no reason to think it wouldn't, i can't say how bare aluminium would hold up over time - but it beats dumping the guide.
Take care if heading down this road to ensure that the clamping surfaces stay accurately flat, and in the original plane. Tilting and/or out of flatness will mess up the bevel angle settings, grip etc. Hand filing probably isn't a good idea.
The headed studs easily press out of the other half of the clamp and back in again (with a touch of high strength thread locker applied under the heads and kept well clear of the threads), so it can (but it's less critical) be flattened on the diamond plate too.
The critical alignment on the guide (when using the cylindrical roller - it's not so important with the barreled version) is that the clamp holds the chisel in the same plane as the roller. (when viewed in the plane of the stone) Mine was accurate (the castings are generally good), although a quick flattening on the diamond plate of the undersurface of the body (the area with the three grooves giving location/bevel angle options the roller assembly) killed off a small amount of slop. (see the narrow bright strips in photo 2) This slop was probably caused by a minor casting imperfection, or maybe excess paint preventing the joint seating properly.
I took it a step further which is optional and to taste - and may be overkill. Done this way it grips like mad with only moderate tightening of the clamp though!
Cautious that the aluminium surfaces might in time mar i filled the depressions in the clamp faces with heat cured 5 min epoxy (140deg F for 4 hrs - max temp, only after initial hardening and don't exceed - gives a full cure and nice hard material that cuts well - pare it back with a sharp chisel and finish on the diamond plate - photo 3) and cut a pair of grippy stainless steel facing plates for them (photos 4,5) from a couple of old and purposely fine grit 'diamond dusted' steel chiropody nail files. http://tiny.cc/0cd7ix
The ones i got felt like roughly P400 wet/dry paper. The epoxy ensures the (thin) plates are fully supported and bearing on a flat surface - they would otherwise probably crease when the clamp is done up. They were secured (to enable replacement if needed - heat to release - but silicone would do it too) with double sided tape. The gripping faces of the diamond files can be rubbed against each other to reduce the 'toothiness' of the grit to taste - left as stock they might slightly mark a highly finished chisel...
The files can (just) be filed to a line when clamped between wood blocks (like when filing the edge of a scraper - photo 4), and the ends rounded on a disc sander. Take care when drilling to keep the rpm down and feed steadily a bit at a time with a toolroom quality HSS or cobalt drill, and use some lubricant and a steel support - stainless steel is tough and one of the files was quite hard. If it's let get hot it'll harden on cooling and won't drill...
Hope this may help a few frustrated with what is conceptually and in most other respects a very nice tool.....
ian
293275293276293278293280293279
A Veritas Mk 2 honing guide bought a few years ago didn't work with my Japanese chisels (photo 1) - i've been getting by with the commonly used Eclipse type.
It wouldn't reliably clamp/hold them - in fact it would hardly hold them at all. The slightly sloped backs worsened the situation, but it wasn't getting much of a grip on flat/parallel backed Western chisels either. A disaster - it's one thing that a honing guide must do well. Others have run into this issue judging by web comments.
Thinking it'd be a pity to dump it given all the nice features and the cost (and having dug it out again i was eyeing the microbevel adjustment) the question became how to sort it out.
The core problem (found in my example) is that the working surface of both clamps (aluminium die castings) is black powder coated. It's a very durable finish, but slippery as hell. The indentations in the surfaces look like they could both have been designed to be fitted with gripping pads which never made it into production…...
This creates the possibility of a secondary problem - the clamp bar with the studs in will likely bend if overtightened in an effort to get enough grip - even heavy finger tightening visibly bows it. (both sides must anyway be evenly tightened on a flat backed chisel or plane blade so that it makes contact acros the width)
Cutting back the working faces of both jaws on a fairly coarse diamond plate to create a flat bare aluminium surfaces results in a fix - a clamp that grips well. (see photo 2) Night and day compared to the original - and able to hold very narrow chisels too.
While there's no reason to think it wouldn't, i can't say how bare aluminium would hold up over time - but it beats dumping the guide.
Take care if heading down this road to ensure that the clamping surfaces stay accurately flat, and in the original plane. Tilting and/or out of flatness will mess up the bevel angle settings, grip etc. Hand filing probably isn't a good idea.
The headed studs easily press out of the other half of the clamp and back in again (with a touch of high strength thread locker applied under the heads and kept well clear of the threads), so it can (but it's less critical) be flattened on the diamond plate too.
The critical alignment on the guide (when using the cylindrical roller - it's not so important with the barreled version) is that the clamp holds the chisel in the same plane as the roller. (when viewed in the plane of the stone) Mine was accurate (the castings are generally good), although a quick flattening on the diamond plate of the undersurface of the body (the area with the three grooves giving location/bevel angle options the roller assembly) killed off a small amount of slop. (see the narrow bright strips in photo 2) This slop was probably caused by a minor casting imperfection, or maybe excess paint preventing the joint seating properly.
I took it a step further which is optional and to taste - and may be overkill. Done this way it grips like mad with only moderate tightening of the clamp though!
Cautious that the aluminium surfaces might in time mar i filled the depressions in the clamp faces with heat cured 5 min epoxy (140deg F for 4 hrs - max temp, only after initial hardening and don't exceed - gives a full cure and nice hard material that cuts well - pare it back with a sharp chisel and finish on the diamond plate - photo 3) and cut a pair of grippy stainless steel facing plates for them (photos 4,5) from a couple of old and purposely fine grit 'diamond dusted' steel chiropody nail files. http://tiny.cc/0cd7ix
The ones i got felt like roughly P400 wet/dry paper. The epoxy ensures the (thin) plates are fully supported and bearing on a flat surface - they would otherwise probably crease when the clamp is done up. They were secured (to enable replacement if needed - heat to release - but silicone would do it too) with double sided tape. The gripping faces of the diamond files can be rubbed against each other to reduce the 'toothiness' of the grit to taste - left as stock they might slightly mark a highly finished chisel...
The files can (just) be filed to a line when clamped between wood blocks (like when filing the edge of a scraper - photo 4), and the ends rounded on a disc sander. Take care when drilling to keep the rpm down and feed steadily a bit at a time with a toolroom quality HSS or cobalt drill, and use some lubricant and a steel support - stainless steel is tough and one of the files was quite hard. If it's let get hot it'll harden on cooling and won't drill...
Hope this may help a few frustrated with what is conceptually and in most other respects a very nice tool.....
ian
293275293276293278293280293279