Derek Cohen (Perth Oz)
Established Member
Blame this on the heat. It is 41.5 C (106.7 F) outside, and probably hotter than this in my double garage/workshop. It has been like this for some days and for much of the time (while I have been on leave from work) I have struggled to maintain enough enthusiasm and concentration for anything more than shortish projects - hence a spate of tool-building and resto work. I sharpenened and played with many of my planes. Which is what I am getting to. But it is early afternoon and I am waiting for the glue to dry on the form work (to laminate Jarrah strips) I have built for two matching half-round end tables. It has been a hot, dirty, dusty (bandsaw and planer-thicknesser) day and hot (did I mention that?) and dusty (in spite of a 2 hp cyclone) morning in a hot and steamy workshop.
A frequent question on the forum is in regard to cambers on smoothers. Now I am not debating whether they are important - I just accept that they are, and all my smoothers have a fine camber to avoid the dreaded tracks that otherwise occur when irons are left straight.
There is the question about honing camber on BU planes, and the answer that BU planes require greater camber to arrive at the same shape shaving as a BD plane.
As I noted, I have been sharpening up all my irons of my planes, and this was partly in preparation for my current project. With the exception of one, these are my planes and I do the best for each. They include: LV BU smoother (cutting angle of 62 degrees), Marcou S15 smoother (60 degrees), Stanley #3 infill (60 degrees), Spier smoother (47 degrees), HNT Gordon smoother (60 degrees), LN bronze#4 1/2 smoother (50 degrees), and LN iron #4 1/2 smoother (45 degrees). The last plane is a loaner. The first three planes are BU and the last four are BD.
Let us go back to that recommendation that camber on a BU iron is required to be greater than camber on a BD iron for the same amount of feathering at the edges of the shaving.
Why then do I consistently find that I require minimal camber necessary for BU planes compared to BD planes? We are talking fine shavings here, finishing shavings. With a straight edge on a BU iron I am able to obtain wafer thin, full width shavings - without tracks. Or, because the shavings are so fine, the tracks are essentially not evident to sight or feel.
With the same straight edge on a BD iron I get full width shavings with tracks. I can also feel that the outer edges of the iron are projecting further than the centre. This is with all the BD planes. I don't understand why - the irons are all honed on the same waterstones, all of which are prepared the same way (in fact I got so paranoid about flattening them with drywall mesh that I have now been using a diamond stone. Still scribbling on a pencil grid to check they are flattened evenly). All the BU irons are honed with the LV Honing Guide Mk II. The BD irons are usually honed freehand. I hollow grind the BD irons and micro grind the BU irons. When I began noticing this effect I swapped to using the LV guide for the DB irons as well. It made no difference. So I discounted the difference in honing strategy - actually, I find it easier to hone a camber on the BD irons when I work freehand.
I will add that all these planes function superbly. They are all capable of high quality smoothing. I am not drawing a distinction between BU and BD in terms of merit. NOT! It is just that they appear to need to be set up differently. Is this my imagination? Or is it the heat?
Regards from Perth
Derek
A frequent question on the forum is in regard to cambers on smoothers. Now I am not debating whether they are important - I just accept that they are, and all my smoothers have a fine camber to avoid the dreaded tracks that otherwise occur when irons are left straight.
There is the question about honing camber on BU planes, and the answer that BU planes require greater camber to arrive at the same shape shaving as a BD plane.
As I noted, I have been sharpening up all my irons of my planes, and this was partly in preparation for my current project. With the exception of one, these are my planes and I do the best for each. They include: LV BU smoother (cutting angle of 62 degrees), Marcou S15 smoother (60 degrees), Stanley #3 infill (60 degrees), Spier smoother (47 degrees), HNT Gordon smoother (60 degrees), LN bronze#4 1/2 smoother (50 degrees), and LN iron #4 1/2 smoother (45 degrees). The last plane is a loaner. The first three planes are BU and the last four are BD.
Let us go back to that recommendation that camber on a BU iron is required to be greater than camber on a BD iron for the same amount of feathering at the edges of the shaving.
Why then do I consistently find that I require minimal camber necessary for BU planes compared to BD planes? We are talking fine shavings here, finishing shavings. With a straight edge on a BU iron I am able to obtain wafer thin, full width shavings - without tracks. Or, because the shavings are so fine, the tracks are essentially not evident to sight or feel.
With the same straight edge on a BD iron I get full width shavings with tracks. I can also feel that the outer edges of the iron are projecting further than the centre. This is with all the BD planes. I don't understand why - the irons are all honed on the same waterstones, all of which are prepared the same way (in fact I got so paranoid about flattening them with drywall mesh that I have now been using a diamond stone. Still scribbling on a pencil grid to check they are flattened evenly). All the BU irons are honed with the LV Honing Guide Mk II. The BD irons are usually honed freehand. I hollow grind the BD irons and micro grind the BU irons. When I began noticing this effect I swapped to using the LV guide for the DB irons as well. It made no difference. So I discounted the difference in honing strategy - actually, I find it easier to hone a camber on the BD irons when I work freehand.
I will add that all these planes function superbly. They are all capable of high quality smoothing. I am not drawing a distinction between BU and BD in terms of merit. NOT! It is just that they appear to need to be set up differently. Is this my imagination? Or is it the heat?
Regards from Perth
Derek
