joeb
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Posts: 11
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Post by joeb on Aug 21, 2023 6:11:03 GMT
Good Morning All, hoping you can help me. I have the Sorby Pro-Edge system with all the attachments and have currently have x2 Sorby 3/8 Fingernail Bowl Gouges; one of which I would like to try out a 50 Degree Long Grind/Sept back grind on. I understand from watching Robert Sorby’s Pro Edge Hint/Tips How To video (& measuring myself) that the factory fingernail grind is 45 Degree Bevel angle and to achieve this from ‘standard grind’ the video shows to first create a Horseshoe at the end of the flute using the table attachment, also set at 45 degrees… Question is however, if I want to go from standard fingernail grind to 50 degree long grind, I understand that I would use the Proset to set protrusion @ 45, then use the second hole on long grind jig, which adds 5 degrees to = the 50… BUT what angle should I make the end of the flute? Should this stay at 45 and just grind the extra wings on? (The video also shows for standard grind the flute is 60 degrees) but for some reason skips this info for both the Long Grind & Extra Long Grind! Or is there a separate flute horseshoe grind when creating long grinds? Hope this makes sense and thank you very much in advance  |
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Post by Pete on Aug 21, 2023 8:12:35 GMT
Hi Joe B
You guessed it right keep the standard 45 "horseshoe" set the tool on the Proset to 45° and use the second hole for a 50° or third for a 55°
Pete
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joeb
New Member
Posts: 11
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Post by joeb on Aug 21, 2023 8:55:34 GMT
Hi Joe B You guessed it right keep the standard 45 "horseshoe" set the tool on the Proset to 45° and use the second hole for a 50° or third for a 55° Pete Hiya Pete, thank you so much for your response & help with this one! This is super helpful. For completeness could I just ask a couple of follow on Q’s if I may. Firstly, if I’m going from 45 fingernail grind to 50 long grind, do I actually need to create a new horseshoe? Or is that only if going from standard grind and so therefore just add the longer wings? Secondly, May I ask out of pure interest what the reason is you stick with 45 horseshoe even if going for different wing grind/bevel angle? Thank you so much again, really glad I found this forum! |
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Post by Pete on Aug 21, 2023 9:30:54 GMT
Hi Jo,
The 45° "horseshoe" is for a guide when converting and more importantly for repairing, it would form naturally anyway the trick and the reason it works well is it gets the wing lengths even before you start so keeps the shape you are after easier to obtain. Remember it though as one day you will hit a bit of barbed wire or a nail!
So no need to recreate it going from 45° to 50° bringing the wings back further will change the angle of the "horseshoe" in the standard fingernail grind anyway. The exception to that is if you are shortening it (say for a 40/40 or removing it to return to traditional where upside down on the table is the fastest way)
The thing to watch out for is both wings need to be the same length, you want a nice preferably straight wing maybe a little convex but NEVER concave, and don't forget the nose otherwise you will develop a hook between the nose and the wing.
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joeb
New Member
Posts: 11
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Post by joeb on Aug 22, 2023 21:55:28 GMT
Hi Jo, The 45° "horseshoe" is for a guide when converting and more importantly for repairing, it would form naturally anyway the trick and the reason it works well is it gets the wing lengths even before you start so keeps the shape you are after easier to obtain. Remember it though as one day you will hit a bit of barbed wire or a nail! So no need to recreate it going from 45° to 50° bringing the wings back further will change the angle of the "horseshoe" in the standard fingernail grind anyway. The exception to that is if you are shortening it (say for a 40/40 or removing it to return to traditional where upside down on the table is the fastest way) The thing to watch out for is both wings need to be the same length, you want a nice preferably straight wing maybe a little convex but NEVER concave, and don't forget the nose otherwise you will develop a hook between the nose and the wing. Hiya Pete, apologies for the delayed response. Honestly, thank you so much for your reply and help with this one! So detailed and fully explains/answered my questions I will ensure to save this information and look forward to giving it a go this weekend! Thanks again, really do appreciate it |
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Post by chrislt on Dec 12, 2023 0:26:14 GMT
Good Morning All, hoping you can help me. I have the Sorby Pro-Edge system with all the attachments and have currently have x2 Sorby 3/8 Fingernail Bowl Gouges; one of which I would like to try out a 50 Degree Long Grind/Sept back grind on. I understand from watching Robert Sorby’s Pro Edge Hint/Tips How To video (& measuring myself) that the factory fingernail grind is 45 Degree Bevel angle and to achieve this from ‘standard grind’ the video shows to first create a Horseshoe at the end of the flute using the table attachment, also set at 45 degrees… Question is however, if I want to go from standard fingernail grind to 50 degree long grind, I understand that I would use the Proset to set protrusion @ 45, then use the second hole on long grind jig, which adds 5 degrees to = the 50… BUT what angle should I make the end of the flute? Should this stay at 45 and just grind the extra wings on? (The video also shows for standard grind the flute is 60 degrees) but for some reason skips this info for both the Long Grind & Extra Long Grind! Or is there a separate flute horseshoe grind when creating long grinds? Hope this makes sense and thank you very much in advance Hi, I am new here and somewhat inexperienced as a turner, but I have studied the geometry of sharpening very carefully. I find much discussion of bevel and wing angles confused. Joeb said he wanted to convert a standard Sorby "fingernail bowl gouge" to "50 degree long grind/swept back grind". Now a standard (non-fingernail) Sorby bowl gouge has 60 degree wings whereas their fingernail bowl gouge has 45 degree wings. So, for Sorby (in the 2018 video) to convert from standard to fingernail by grinding a horseshoe at 45 degrees is correct. But joeb is surely wrong to say "the factory fingernail grind is 45 Degree Bevel angle and to achieve this from ‘standard grind’ the video shows to first create a Horseshoe at the end of the flute using the table attachment, also set at 45 degrees". This is because the horseshoe is nothing to do with the bevel angle. It relates only to the wing angle. In fact all these gouges have a 45 degree bevel angle at all times. Joeb wants to change the wing angle from 45 degrees to create a "long/swept back" grind. He refers to this as 50 degrees but I would rather call it 30 degrees, measured, like the bevel, from the axis. Anyway, to change the wings from 45 degrees to 30 degrees you DO need to start by setting the platform to 30 degrees and grinding a new horseshoe at this angle. Also, using the long grind jig does NOT change the wing angle by 5 degrees per hole. It changes the bevel angle by 5 degrees per hole. Actually, the long grind jig doesn't affect the shape of the wings in any way. It merely overcomes the problem that you need to swing the jig by more than 90 degrees and this can snag on the base of the machine. So, if you want a "long" or "extra long" fingernail wing shape (35 or 30 degrees) start by setting the platform to 35 or 30 and forming the horseshoe. Then, for a 45 degree bevel use the ProSet extension normally used for 40 or 35 degrees for a "long" or "extra long" fingernail respectively. By the way, in my studies I have found a great deal more wrong with the Sorby geometry, or rather with how Sorby tell you to set it up, but that's another story. |
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Post by Pete on Dec 12, 2023 9:10:37 GMT
Hi Chrislt
it is a mistake to get too hung up on exact angles and geometry, what you need is a sharp cutting edge preferably mostly consistent. Take the jigs out of the equation and sharpen by eye and you can still get a traditional grind or a fingernail grind that will cut the timber perfectly, and you will never know exactly what the angle is.
With the ProEdge and it's fingernail jig if you take a traditional 45° grind without any wings measure the width of the tool and mark a line on it that distance from the end. Set the jig to 45° and use it to guide the sharpening back to the lines you have marked forming a wing, those wings will be approximately 45°, and will cut very well the parabolic flute will create the sharp wings.
The purpose of wanting a 50° to 60° angle on the bevel is simply to allow the cutting edge to flow around the bottom corner and over the base of a bowl riding on the bevel with perfect presentation of the cutting edge to the wood fibres.
It is sensible to have a consistent bevel all the way around the tool, though many great turners use an asymmetric grind with the wing only on one half or a different wing profile on each side, usually sharpened by eye without a jig, there are reasons but not really relevant to this post.
Consistent, sharp, controllable is what the ProEdge will give you, trust the settings and the jigs and cut shavings not get bogged down in the math.
Enjoy your journey.
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Post by chrislt on Dec 14, 2023 23:39:18 GMT
Hi Chrislt it is a mistake to get too hung up on exact angles and geometry, what you need is a sharp cutting edge preferably mostly consistent. Take the jigs out of the equation and sharpen by eye and you can still get a traditional grind or a fingernail grind that will cut the timber perfectly, and you will never know exactly what the angle is. With the ProEdge and it's fingernail jig if you take a traditional 45° grind without any wings measure the width of the tool and mark a line on it that distance from the end. Set the jig to 45° and use it to guide the sharpening back to the lines you have marked forming a wing, those wings will be approximately 45°, and will cut very well the parabolic flute will create the sharp wings. The purpose of wanting a 50° to 60° angle on the bevel is simply to allow the cutting edge to flow around the bottom corner and over the base of a bowl riding on the bevel with perfect presentation of the cutting edge to the wood fibres. It is sensible to have a consistent bevel all the way around the tool, though many great turners use an asymmetric grind with the wing only on one half or a different wing profile on each side, usually sharpened by eye without a jig, there are reasons but not really relevant to this post. Consistent, sharp, controllable is what the ProEdge will give you, trust the settings and the jigs and cut shavings not get bogged down in the math. Enjoy your journey. Thanks for your thoughts, Pete. I don't believe I am hung up on exact angles but I do think it's probably best to have roughly the same bevel angle all along the gouge's cutting edge. The bevel angle produced by a jig varies by up to 15° from tip to wingtip. But I haven't yet tried grinding two gouges in the two different ways (one on a platform, the other with a jig such as the Sorby fingernail jig) and trying them out to see if one works better. My concerns may turn out to be unimportant in practice. |
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Post by Pete on Dec 15, 2023 15:29:31 GMT
Thanks for your thoughts, Pete. I don't believe I am hung up on exact angles but I do think it's probably best to have roughly the same bevel angle all along the gouge's cutting edge. The bevel angle produced by a jig varies by up to 15° from tip to wingtip. But I haven't yet tried grinding two gouges in the two different ways (one on a platform, the other with a jig such as the Sorby fingernail jig) and trying them out to see if one works better. My concerns may turn out to be unimportant in practice. I have cut many miles of shavings using the fingernail jig on the ProEdge only ever measuring the distance from jig to tip (on the proset) and repeating the hole I use on the 3 hole long grind to modify 45° proset distance to 45° ish, 50° ish or 55° ish I think I may out of curiosity have measured the actual bevel angle once, shrugged, and got back to making shavings which is the main reason for owning a lathe I do manually produce the 40/40 grind and I am fairly careful that one is right, that is my practice for non jig sharpening |
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yulan
New Member
Hi thanks for looking hope I can help
Posts: 11
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Post by yulan on Mar 22, 2024 12:49:16 GMT
Hi Joe B You guessed it right keep the standard 45 "horseshoe" set the tool on the Proset to 45° and use the second hole for a 50° or third for a 55° Pete Hi I went a used this link below, The only difference the chisel I used the 45 length gauge.https://www.youtube.com/watch?v=r_lzrK4UVTQ |
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Post by Pete on Mar 23, 2024 21:02:17 GMT
Hi Joe B You guessed it right keep the standard 45 "horseshoe" set the tool on the Proset to 45° and use the second hole for a 50° or third for a 55° Pete Hi I went a used this link below, The only difference the chisel I used the 45 length gauge.https://www.youtube.com/watch?v=r_lzrK4UVTQ That grind is way too pointy for my liking the transition inside the bowl would be a very dangerous prospect, OK for hacking timber off the outside but most timber worth turning wouldn't work well with that big a cut at 1000rpm 6-10mm width shaving unless the wood is wet and a bit boring in the grain. |
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