question for MKII users (Lyn? others?) - long

Re: question for MKII users (Lyn? others?) - long

Lyn J. Mangiameli

>1) Do you all agree that I should stop using the progression of grits I've been using (btw, I only use the very coarse grits for initial flattening and/or changing primary bevels)?

2) If you say "no" to #1, how are you doing with your MKII and what are your suggestions?

In reply:

There is nothing the matter with the progression of grits you are using. Your current progression will reduce heat generation and sharpening time, while increasing abrasive life.

Your problem is in when you switch to the thinner 3mm platters. I have no thin platters mounted with anything coarser than 20 micron (around 500 grit) and don't generally use that for establishing and maintaining microbevels. I usually use 9 mm abrasives to establish the microbevel and often only 5 micron or even less. As you know, you only need the slightest microbevel for it to have a significant effect on edge life and sharpening ease. As that microbevel becomes worn and thus wider over time, maintainance may require the 9 mm or even up to 20 mm papers to effectively renew it. But for initial estabishment or re-establishement after work on the primary bevel, I'd go with 9 mm or less.

Its a simple change and will entirely eliminate your problem. Just pick up another thick 4 mm platter or two to accommadate the abraives ranges you have currently been using with the thinner platters. You can use the then surplus thin disks for .3 micron papers or for use with honing compounds.

good idea & more observations

Mike in Mystic

>Hi Lyn,

That sounds like a good idea. My initial reasoning for using so many grits on the thin platters was to increase the number of graduations on the microbevel so as to most efficiently and uniformly develop the keenest possible cutting edge.

Before I saw your reply I was out in the shop for quite awhile and was determined to rectify my technique so I started sharpening several tools that I hadn't used with the MKII yet. I started out on a 6 piece Two Cherries bevel edge chisel set, then a 4 piece Henry Taylor butt chisel set. I moved on from there to a couple 2" wide old plane irons, and then a 2 3/8" wide old one. My coups de grace was the brand-spanking new iron to my L-V 4 1/2 (which I only received yesterday).

A few observations:

1) It seemed easier to achieve a nice narrow and uniform microbevel on the butt chisels vs. the longer bench chisels. I made sure to set up the tool rest appropriately so they both should have had a 25 degree primary bevel. perhaps my technique was improved enough at that point?

2) Using light pressure is definitely the key. By the 2nd chisel I was getting much better results simply by letting the tool's weight do most of the work. I did put a small amount of pressure, but only in about one second increments. By the time I was about about 20 micron grit I only touched the edge to the disk about 3 times before moving on.

3) Achieving very nice microbevels was especially easy on the plane irons, even compared to the butt chisels. Again, I have no idea why this would be. Nonetheless, I was very happy with the results by this time. I should note that I didn't mess with the primary bevel on the L-N iron, but started out at 20 microns on the microbevel.

4) If you are sharpening this many things and can't help but to do the "shave hair from your arm/hand" test, remember to alternate arms or you'll end up like this:

Left Hand

Right Hand

As you can see, I'm right handed hehe.

The REAL result that is even more interesting is that after I put the iron back in the 4 1/2 I was able to easily produce wonderful wispy shavings of approx 0.0005" thickness (a single shaving wasn't registering on my digital calipers, but when I put 3 together the reading was 0.0015"). Before the sharpening I was only able to get them down to about 0.003".

Anyway, I'll stop worrying over nothing now, but I do think I'll order another thick platter and stop being so heavy-handed.

Mike

Aha, Woodworkers Pattern Baldness !! NM

Dave Anderson Chester,NH

>NM

My observations...Lyn??

Jonathan Ronnow, Sweden

>... using the neander qpss - the veritas guide on microabrasives on glass. I renew the primary bevel with whatever it takes - If its nicked I use 120 micron, followed by 80 and 50 micron. And 15 if Im in the mood for shiny. I usually stop there.

So much for the basic bevel. Now my theory begins, and this is where I need you help Lyn:

I go up 1 degree from basic bevel with the cam setting and do about six back-and forth 1 1/2" long strokes on the 5 micron. Then up 1 degree more and do about 6 more 1 1/2" strokes on that. Then its _really_ sharp. Why 1 1/2"? To keep the roller, and with it coarser grit, off the abrasive film. Anyway...

If it takes me say 12 * 1 1/2" = 18" of linear travel to establish a secondary bevel, and 18" more for a thertiary(or whatever its called - remember im swedish =) )bevel, then that should not translate to many seconds on a platter spinning at 650 rpm...?

Ok this is all theory since I dont have the qpss to try it, but... Am I off on this, Lyn?

Just a though Ive had.... I use a secondary bevel about 3-4 hairs width and third-whatsthename about 1 hair wide...

I assume it does partly come down to what type of blade and why the microbevel, but if its for speed and ease of sharpening I think less time & abrasive spent, and more metal kept intact.

Jonathan

Re: My observations...Lyn??

Lyn J. Mangiameli

>Jonathan, I'm terribly sorry for this late reply, I somehow missed your posting until today.

Your experience sounds consistent with mine, both using manual and powered techniques. Multiple microbevels with very small increments in bevel angle definitely shorten the necessary time for refining the edge, as less surface area must be refined. And yes, for initial preperation of those microbevels, almost regardless of alloy, the time required by hand or by power is very brief indeed.

The QPSS achieves those small microbevels in two ways. The first is the reduction in platter thickness for the finer grits. Coarse grits are sharpened on a 4 mm platter, finer grits use a 3 mm thick platter. The second way results from the size of the abrasive itself (and sometime the thickness of the backing material). Coarser grits just have larger particles that make for greater thickness of the combined platter/abrasive sandwich (and often further supplemented by their thicker backing materials). Thus, the QPSS and its predecessor actually apply many small microbevels to the blade. If these are allowed to remain, as opposed to more extended sharpening that will remove them with the next finer abrasive, the sharpening time can be very very brief.

Though your LV hand honing guide achieves its changes in bevel angle through the eccentric axis of the roller, it too is positively affected by particle/backing thickness of abrasive papers if the roller is not located on the abrasive, but kept on a surface of consistent height. Of course this doesn't occur when the roller rides at the same height (usually the same surface) as the abrasive. Thus the eccentric cam is of great value in the typical hand held situation.

Despite all of this, the width of the final secondary/tertiary, etc microbevel will increase with repeated honing at the angle, which is what most woodworkers do to renew the sharpness of their edge. Of course, as that width increased, honing time will increase, even if only slightly (but with some alloys, that increased time can be appreciable). Then one can decide to do any of three things. 1. Accept the additonal time required for honing the now great than "micro" bevel and continue to renew the edge at that same geometry. 2. Go back down to coarser abrasives and work up to establish a new thin microbevel of the same geometry. Or 3. Establish an new microbevel of slightly higher bevel angle.

The latter is actually a most efficient way to reduce honing time with an edge that is ofen renewed, but doesn't require major reworking. The reason it is not done more often is that many woodworkers lack a convenient way to precisely achieve very small changes in bevel angle. Wouldn't it be great if the LV honing guide, instead of an eccentric cam with its limited number of (relatively) large increases in bevel angle, instead had a means of infinite adjustment that would allow multiple changes of just 1/4 degree or more. This would shorten honing time with even the most wear resistant steels, but allowing several microbevels to be established over time, but with all of them adding up to little if any functional difference in cutting geometry.

As I commented, the QPSS achieves this very effect by going to finer,smaller abrasives, and the honing time never amounts to much even with quite a wide microbevel. But with a manual system, the multiple microbevel could be a quite nice thing when dealing with wear resistant alloys and/or less efficient abrasives.

I hope this was on track with your question, if not, let me know and I'll try again.

Lyn

Infinite Adjustment

Steve Elliott

>

Wouldn't it be great if the LV honing guide, instead of an eccentric cam with its limited number of (relatively) large increases in bevel angle, instead had a means of infinite adjustment that would allow multiple changes of just 1/4 degree or more.

The Millers Falls #240 honing jig allows for infinite adjustment. Although it is no longer in production, it often shows up on ebay and sells for $30 or so. I've modified mine by replacing the roller with a shaft that serves as an axle for wheels that don't ride on the abrasive surface.

Here are some pictures:

Since I took these pictures, I've lengthened the axle to allow the blade to move farther to the left and right. To make the jig work accurately, it is important that the axle be exactly centered in the wheels. Otherwise, the blade is tipped slightly from side to side producing a convex edge. I made these wheels out of Bakelite, and drilled the center hole in a rough blank. Then I used the edge sander and a jig with a peg for the center hole to true up the edges.

My favorite method of honing is still to hollow grind, then freehand hone using the front and back of the hollow to determine the honing angle. This only works on relatively thick, not-too-long blades. For Bailey style blades or high-alloy steels that are unusually abrasion resistant, I like this jig.

Re: My observations...Lyn??

Jonathan Ronnow, Sweden

>As always you have some very fine points Lyn....On track.

Ive never even had the idea of changing the angle by only 1/4 degree or so... but indeed it sounds interesting. I suppose I could fiddle with the LV guide and make more stop positions for the cam. Should be pretty easy with some means of accurate holding and an end mill....

I wouldnt mind that since there will be a new guide availiable. Or if I trash it completely I could always get a new one.

I will try to machine more stops. I think there is a practical limit at say 1/4 degree stops, more than that and there isnt much seating between the cam knob and the body of the guide I think. Also, it will be hard to know where in all those 1/8 degrees you are..... overkill?

While the Millers Falls #240 solves the infinite adjustment problem I think it creates one of lack of repeatability. I think repeatability is esential if its going to save time and effort.

Quote Lyn : "The reason it is not done more often is that many woodworkers lack a convenient way to precisely achieve very small changes in bevel angle"

I agree, if it is to be useful it has to be a) precise b) fast and c)repeatable.

What say Lyn? How much increase in the microbevel can be tolerated before it is better to renew the intended geometry?

Also, some means of documenting the existing angle has to exist, otherwise there is no point fiddling with quarter degrees. Do you mark your tools with the bevel angles Lyn? Say 25/26/27

as in main/second/tertiary(learned how to spell that now)?

Jr - guess my friend at the metalworking shop has one more project now...

Re: My observations...Lyn??

joel

>Jonathan,

in one of your previous posts you point out that your microbevel is truly micro, and in another you mention you mostly free hand sharpen which of course references off of your exsting primary bevel.

You do say you can't free hand thinner blades which is when you use a jig.

Might I suggest a couple of things:

First: since you are creating a true microbevel of only a few thou" width you can easily remove it on the next sharpening by going back to the original bevel. This is one of the great advantages of free hand sharpening - the reference is always repeatable. By only having a primary bevel and then a single micro bevel which is removed each time, you avoid all the repeatibity problems. now it's true when you free hand a micro bevel you may not have the exact same microbevel angle as before but as lyn points out 1/2 a degree can't make that much of difference and you save all the machinations of trying to build a bevel on top of a bevel.

As for free hand sharpening thin blades or long tools it's certainly harder than a thicker, shorter blade but you are almost there - it's mostly practice and on the heavier tools learning to support the tool just enough so the dominent hande that presses the bevel flat can do it.

Certainly you are aware of the speed advantage you get with free hand sharpeing both in setup speed and not having to sharpen on tool completely before changing to another tool.

So what I would suggest is that you mostly on the way to a good solution, you just need more practice.

note: hollow grinding saves a lot of effort too.

Yesterday I needed to sharpen a brand new plane iron. I timed it. 90 seconds to hollow grind it.

just under 3 minutes to sharpen it. Not really my best times but pretty average considering I wasn't rushing and wanted to do a really good job. THe back was pretty flat - if it wasn't it would have been returned to the maker.

me?

Jonathan Ronnow, Sweden

>"in one of your previous posts you point out that your microbevel is truly micro, and in another you mention you mostly free hand sharpen which of course references off of your exsting primary bevel.

You do say you can't free hand thinner blades which is when you use a jig. "

Will all do respect, but I think you�re mixing me up with someone else joel... I have nearly always used honing guides, well almost anyway. But I never (free)hand hone, I rough the bevel with machine and hone with the veritas guide, before I bought it I used the eclipse.

If I freehand its because I dont have the guide or because Im experimenting... But I use the guide 99% of the time now...

Jonathan

Re: me?

joel

>Whoops -

I went back and put everything back in order. Yep - I confused you with Steve. Sorry about that. I think your reference to the miller's falls confused me.

All I would say is my suggestion doesn't solve your specific condition at all but it will provide an easily repleatable way of maintaining the geometry of sharpening for anybody.

Re: me?

Jonathan Ronnow, Sweden

>thats ok... I suspected that is was that way :)

I agree that the freehand method is a good one; Ive read the guide to honing several times. I follow it when I am freehanding, although it happens more and more seldom now.

Jonathan