Author Topic: Chisel and plane sharpening  (Read 4656 times)

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Offline derekcohen

  • Posts: 322
    • In The Woodshop
Re: Chisel and plane sharpening
« Reply #30 on: May 04, 2019, 09:37 PM »
Free hand May be the fastest way but, for most of us,  the most reliable way is to use a jig like the LN. I get the exact same result every time and it really doesn’t take much longer to establish the correct exposure for the desired angle with a simple homemade gauge. ...

It is not only fast, but angles are repeatable (for BD plane blades and chisels) if you first hollow grind to the angle you want, and then simpy freehand hone on the hollow. The hollow acts as a jig (no jig to set up). If you use a honing guide to create a secondary bevel, this will creep up and become excessively large, and at some stage you will need to re-grind the primary bevel anyway.

Freehanding on a hollow cuts out the unnecessary, and is much faster and just as reliable as a honing guide. When someone says that they are not in the shop enough to learn this, I remind them that I am also a weekend warrior, and it was no big deal to master the technique. I have used every method under the sun, and this is the one I decided works more efficiently for me.

Regards from Perth

Derek


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Offline RKA

  • Posts: 1667
Re: Chisel and plane sharpening
« Reply #31 on: May 04, 2019, 11:13 PM »
I feel like I’m following your path Derek (trying this and that).  One question I had is why the jig for the BU blades but the hollow grind method for BD?  Is it because you’re putting a high angle on the BU and you don’t get the same solid registration as you do on other blades with lower angles? 
-Raj

Offline derekcohen

  • Posts: 322
    • In The Woodshop
Re: Chisel and plane sharpening
« Reply #32 on: May 06, 2019, 11:02 AM »
Hi Raj

Modern blades tend to be thicker and use steel that is more abrasion resistant than high carbon types (such as O1). Modern steels include A2 and PM-V11.

It is notably the BU planes that require a different sharpening strategy from BD planes. First off, the blades from LV are typically 3/16” thick. Secondly, all planes (BU and BD) need to camber the blades to avoid tracks when planing face grain. Thirdly, high cutting angles (I only use a bevel of 50 degrees, but the rule applies for lower angles as well) are needed for BU planes to avoid tearout with interlocked wood. The net result of attempting to freehand a camber on a 50 degree bevel on a thick abrasion-resistant steel scared most BU users away from doing so for many years. Some still have not got the message that there is a simple method to do so.

1. To camber a high angle BU blade you always use a honing guide. I freehand all my other blades - chisels and BD plane blades (on a hollow grind) - but BU plane blades need a guide to get the bevel angle correct.

2. Only ever use a 25 degree primary bevel. Never hone a full angle bevel, such as 50 degrees. Instead, add the 50 degrees as a secondary micro bevel to the 25 degree primary bevel. Add your camber while doing this. There is significantly less steel to remove this way. Honing and cambering BU plane blades can be a quick process.

My system for BD plane blades and all Western chisels is to freehand on a hollow. This creates a coplanar microbevel. An analogy is that this is similar to using a Japanese blade, which is hollowed (relieved) on the back to speed up honing hard steel. Working on the full hollow, rather than freehand creating a secondary micro bevel (tipping the blade), ensures repeatability of the cutting angle.

The quality of the hollow determines the speed at which you can hone. As full a hollow as possible - that is, as close to the edge as you can get without burning steel - reduces the steel to hone and speeds sharpening time, especially with abrasion-resistant steels. The two systems I recommend are the water-cooled Tormek and, better still, a 180 grit CBN wheel on a half-speed bench grinder. The CBN system is fast but also runs cool.

With this system it is possible to hone the first grind with a 5000 grit waterstone, and then proceed to the final polishing stone. I only need 2 or 3 swipes with each. That is fast. As the micro bevel grows, and it does this slowly, add in a 1000 grit stone. I generally re-sharpen about 5 times before touching up the hollow. Note that steel is removed from the hollow and not the length of the blade.

Regards from Perth

Derek

Offline RKA

  • Posts: 1667
Re: Chisel and plane sharpening
« Reply #33 on: May 06, 2019, 01:03 PM »
Thanks @derekcohen !  I don't even want to know how many hours and years you've spent trying and perfecting your methods.  I've only done the hollow grind on the chisels thus far.  All the plane blades were done on a jig.  I've been hesitant to try the plane blades because I have a narrow cambered CBN wheel (toolsforworkingwood).  I can do a pretty good job freehanding up to a 1" chisel keeping the leading edge relatively straight, but with a 2" wide plane blade I think I need a tormek style blade holder for my grinder in order to rake the blade evenly across the cambered wheel.  I guess I'll never know unless I try to freehand it first and see how badly I screw up my blade?  I'm a scared-y cat.  :-P

Edit:  I went digging around for more details on cambering blades (BD and BU) and found the following written by Derek.  I think it goes into exhausting detail about how he arrived with his recommendations.  I've only gone through half of it, but I thought it would be good to add the link below in case anyone else has the same questions.

https://www.inthewoodshop.com/WoodworkTechniques/TheSecretToCamberinBUPlaneBlades.html
« Last Edit: May 06, 2019, 04:11 PM by RKA »
-Raj

Offline grbmds

  • Posts: 1906
Re: Chisel and plane sharpening
« Reply #34 on: May 06, 2019, 01:40 PM »
Free hand May be the fastest way but, for most of us,  the most reliable way is to use a jig like the LN. I get the exact same result every time and it really doesn’t take much longer to establish the correct exposure for the desired angle with a simple homemade gauge. ...

It is not only fast, but angles are repeatable (for BD plane blades and chisels) if you first hollow grind to the angle you want, and then simpy freehand hone on the hollow. The hollow acts as a jig (no jig to set up). If you use a honing guide to create a secondary bevel, this will creep up and become excessively large, and at some stage you will need to re-grind the primary bevel anyway.

Freehanding on a hollow cuts out the unnecessary, and is much faster and just as reliable as a honing guide. When someone says that they are not in the shop enough to learn this, I remind them that I am also a weekend warrior, and it was no big deal to master the technique. I have used every method under the sun, and this is the one I decided works more efficiently for me.

Regards from Perth

Derek
[/quote

Completely understand the process. I just do a better job with a jig and that's why I continue to use one. Many professional woodworkers use a jig also because it's the most reliable for them. We all have our ways of doing things and do what works best for us. I think it's great when people do freehand sharpening/ honing. Just not me.
Randy

Offline derekcohen

  • Posts: 322
    • In The Woodshop
Re: Chisel and plane sharpening
« Reply #35 on: May 07, 2019, 06:12 AM »
Randy, I have long stated that the important element in woodworking is the building, not the sharpening. No one looks at a piece you have built and asks how you sharpened, or whether you freehanded or used a honing guide :)

How you do it is a personal preference. There are lots of methods that work.

Regards from Perth

Derek

Offline tackdriver

  • Posts: 2
Re: Chisel and plane sharpening
« Reply #36 on: May 31, 2019, 05:02 PM »
Using a small secondary bevel also saves wear on your stones and reduces the need to reflatten them as often.