Grinding Veritas BU plane blades (on CBN wheel)

[Mike Holbrook]

I have some older Veritas BU, A2 plane blades. I was curious about how hard it might be to hollow grind slightly cambered edges on these heavy blades using a CBN wheel. I had been thinking about Derek Cohen's suggestion to grind all BU blades to 25, adding micro bevels to get whatever final bevel needed. The problem I have with using that method is it pretty much demands the use of a sharpening jig to make the final small bevel and I am a hand sharpener. I tend to use old Stanley planes for rough work and my BU planes for the fine work so I was not looking for heavy cambers on the BU planes.

I have two PM-V11 BU blades that I want to hollow grind. I did the testing with the A2 blades in order to figure out what to do to the new PM-V11 blades. The A2 blades will not see much use once I get the PM-V11 blades ready anyway. I ground a roughly 38 BU blade to 25 and a 25 to 30. Yes, I had to grind both bevels entirely off, replacing them with entirely new bevels. Although it did take a little time it was not hard or as time consuming as I feared it might be. I was pleasantly surprised that I was able to regrind the two bevels without shortening the blades too much.

I ground one blade at 30 because this is the angle Veritas grinds all their Custom PM-V11 blades at. Derek also made a post about a test he did comparing the surfaces made with several different smooth & jointer planes, using irons with and without chip breakers. A Veritas Custom #4 with a 42 degree frog and 30 degree BD blade produced the best result, eeking out the ever popular Veritas BUS, with I believe a combined 62 degree angle. A 30 degree bevel in a 12 degree BU plane has the same 42 degree combined angle. I recently ground a 8" camber in a Veritas 1 3/4" PM-V11 blade for Stanley type planes at 30 to use in a 5 1/4 Stanley I restored. I was pleased with how this blade worked in the 5 1/4.

I will be switching the 25 & 30 degree A2 blades back and forth between Veritas: LA Jack, BUS Smoother and BU Jointer to test them further but so far I am liking the 30 degree blade both in the BU planes and the Stanley 5 1/4 with the PM-V11 blade.

[Pat Barry]

Are you doing this freehand or do you have some sort of guide and tool rest to ensure you do this bevel uniformly even all the way across and maintain perpendicularity to the edge?

[Mike Holbrook]

Are you doing this freehand or do you have some sort of guide and tool rest to ensure you do this bevel uniformly even all the way across and maintain perpendicularity to the edge?

Pat, I have a SB tool rest from Woodworking Emporium. Very heavy duty rest with a curved back edge, other than the rest I do the work free hand. I mark the back of the blade to give me a reference mark. The work is not hard to do, just a matter of adjusting how long and at what angle the blade touches the wheel. I use a 4" LV square to check for a uniform curve across the edge. The blade does not usually get more than warm during the process so I do not worry about grinding at the edge either. The grinding goes at a pace that makes progress steady but not too fast. The finished product looks uniform, a cursory look might not distinguish it from what a machine might turn out.

[Derek Cohen]

I have some older Veritas BU, A2 plane blades. I was curious about how hard it might be to hollow grind slightly cambered edges on these heavy blades using a CBN wheel. I had been thinking about Derek Cohen's suggestion to grind all BU blades to 25, adding micro bevels to get whatever final bevel needed. The problem I have with using that method is it pretty much demands the use of a sharpening jig to make the final small bevel and I am a hand sharpener. I tend to use old Stanley planes for rough work and my BU planes for the fine work so I was not looking for heavy cambers on the BU planes.

Mike, I would not trust a grind, hollow or flat, to be precise enough for the very, very fine camber that you use in a smoother. A jack plane is a different kettle of fish. It is much coarser.

Adding a secondary micro bevel requires a honing guide if you want to be precise. I use one.

A Veritas Custom #4 with a 42 degree frog and 30 degree BD blade produced the best result. A 30 degree bevel in a 12 degree BU plane has the same 42 degree combined angle.

This is incorrect. A BU plane has a cutting angle of the bed angle + bevel angle (12+30= 42 degrees). The BD plane takes its cutting angle from the bed/frog. This could be 45/50/60 degrees. It is coincidental that the frog I used was 42 degrees. What made this combination superior was the use of the chipbreaker, not the bevel angle or the cutting angle.

Regards from Perth

Derek

[Mike Holbrook]

Thanks for the interest Derek. Now we are getting into the specifics I have been interested in.

I have been working some very twisted cherry a friend, machine woodworker, gave me as a challenge. Maybe not what you work in Australia but about as difficult as I think I will typically try to tackle. I was not trying to produce finely tuned smoothing for my current work. I was interested in finding out how precisely I could grind bevels with just the SB rest. I was surprised at how accurate I could make a fine curve. The results were reasonably close to the results Schwarz shows in his video on fine tuning a smoothing plane... as far as my naked eye can see which granted may not be all that accurate.

I understand how to calculate the combined cutting angle for a BU plane and the fact that a BD plane's cutting angle is a result of frog angle and not the blade angle. I was actually just explaining why I decided to grind one blade at the typical 25 and the other at 30. I was particularly interested in 30 as I believe you have mentioned that grinding angle as working well in other posts/articles. I have recently started grinding just about all my hollow ground blades at 30 instead of 25. I believe 25 is the angle you have suggested for grinding all BU planes, as a starting point for micro beveling them.

I believe the frog you used on the custom #4 was 42. There is a fair amount of information discussing how you came up with 42. I think you mention Warren's favorite Stanley #3 with a custom 42. Maybe a BU plane with a 12 degree bed and a 30 degree blade is not the same as a BD plane with a 42 degree frog and 30 degree blade? Still I was interested in that angle of cut as an all purpose angle for BU planes for the work I do. I know the bevel is irrelevant to the BD cutting angle of the frog but it is still relevant in terms of how the blade cuts and lasts isn't it?

Most of the plane work I have done in the last two years has been rough work for chair/table/bench legs where speed was the big issue and there are precious few flat surfaces. Now I am starting to build more typical pieces, still the furniture I want to build will have rougher surfaces, to go in a log/timber framed house. Some of the "furniture" I see in these houses is made from actual sticks with the bark still on them. The more formal pieces, table tops for instance, still have fairly rough surfaces compared to pieces like the cabinet you are making now.

I am approaching the idea of a smoothing plane from a little less accurate requirement than may be typical on this forum.

[Derek Cohen]

Hi Mike

The BD Custom #4 with the 42 degree frog was only able to plane interlocked grain because the chipbreaker was used to control tearout. This is a very different result than if the #4 had been used without the chipbreaker, or the chipbreaker pulled by. Then it would assuredly have torn out.

In the above situation, the bevel angle does not matter if it is 25 degrees or 30 degrees. I recommend the latter for BD bench planes since anything lower - no matter the steel type - will not hold an edge long. Indeed, some prefer a 35 degree bevel (except that is not recommended for a 42 degree bed owing to there being just 7 degrees of clearance). Use 25 degrees for the primary bevel on BU planes.

While I did test the Custom planes without the chipbreaker, that was only with the 50 degree frogs. All tests with the 40- and 42 degrees frogs were done with the chipbreaker.

Regards from Perth

Derek

[Mike Holbrook]

Thanks again for your comments Derek. I have been on a quest to regrind all my plane blades with hollow grinds. I have grown to appreciate the PM-V11 plane blades over the last few months. I bought three PM-V11 blades, 1 3/4, 2 & 2 3/8 for Stanley type planes. I have been "honing" my hollow grinding skills on some of the old Stanley plane blades before risking the PM-V11 blades. It occurred to me that it might be a good idea to do some similar skill refinement with my old A2 BU blades before risking the PM-V11 BU blades that came with them. I did grind the 1 3/4 PM-V11 blade at 30 with a 8" radius and I have been pleased with how well it is working in a Stanley 5 1/4.

Although I understand that the 42 degree frog on Derek's Custom #4 may not be the relevant factor he was interested in for his chip breaker test, I have been looking for a "better do it all" angle to hollow grind BU plane blades at. I know Derek grinds all BU blades at 25 and then grinds micro bevels to achieve final angles. As Derek has mentioned doing this requires an accurate guide to assure that the micro bevel is precisely ground. However, I am trying to find a work around for honing final micro bevels with a guide. I plan to use the three Stanley PM-V11 blades in Stanley planes for most of my rough work. I am planing on using my BU planes more as medium planes, following Schwarz's idea of course/medium/fine planes. I am still working on how to tune specific planes for smoothing. As I mention above, I may not need the ability to smooth surfaces to the degree that many on these pages do.

I am interested in planes with chip breakers. However, depth of cut on the fly, is my hot button. I have been poring over Derek's study of the Custom Veritas planes, trying to evaluate how easy/accurate they may be compared to BU & BD planes. I may be guilty of trying to read between the lines. I am often challenged by the frequent need to adjust depth of cut. Part of my personal challenge is, I find it hard to adjust plane depth visually these days. Adjusting blade depth by feel and the shavings ejected is appealing. I would prefer not to have to stop and readjust blade depth under a magnifying light every few minuets.

I am experimenting with learning to adjust depth of cut on the fly with my old Stanley planes and I will keep at it until I feel like I have a decent mastery of how to do it. The Stanley planes I have may require more: knowledge\ refined skills \fiddling with adjustments than I find palatable. Should I find the Stanley planes too hard to use I will relegate them to rough work and find another solution for the fine work, as Derek seems to have done with the Veritas Custom planes with chip breakers. I may consider a Veritas Custom BD plane down the road, more for ease of use and more precise adjustments than the smoother cuts.