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Executing a push cut correctly... (Read 681 times)
 
Don Stephan
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Re: Executing a push cut correctly...
Reply #15 - Nov 6th, 2017 at 8:08pm
 
If you see bruising, you may be pushing against the wood, which can cause bouncing and poor cut.

I use my coarse wheel to grind back the heel up to within 1/8" or even 3/32" of the cutting edge, no idea what the actual angle is.
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robo_hippy
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Re: Executing a push cut correctly...
Reply #16 - Nov 7th, 2017 at 1:57am
 
My videos are old enough that I can't remember them well any more...

The 45/45 is the same as Stuart's 40/40, which he says can not be duplicated with a jig. So, platform at 45 degrees, and sweep and roll to the sides just past the mark/line which is at 40 degrees. He rolls it a bit past horizontal or level, I think anyway. I was mentoring and the student bought his gouges with him which were all jig ground, and to me, his wings were much more acute/pointy than mine. Stuart says his wing bevel is the same as the nose, which would make that true, but some thing I had not noticed.

The 'secondary' bevel is a strange concept to me because it is not a bevel that is used. I just round mine over free hand on the wheels rather than setting a separate angle, which takes too much time to me. The reason for this 'relief' is so that the cutting edge is closer to the bevel rubbing spot on the inside of a bowl or any convex surface. With a concave surface, there is no difference in the rub spot, no matter which bevel angle you use. I round over rather than second or third bevels to remove any sharp edge. Any sharp edge can and will leave marks.

Perhaps the most difficult skill I had to learn was the proper bevel rub, which is no pressure at all on it. Brute strength comes in handy on heavy scraper use for stock removal on bowls, but it is terrible for finish cuts. The lighter that bevel touch is, the smoother and cleaner your cuts are. Still working on perfecting this cut...

Next video out will be about shear scraping. The shooting is done and camera man is editing. I only use scrapers for this, and only V10 or M42HSS for my tools (Doug Thompson and Dave Schweitzer/ D Way tools). Far superior to M2HSS. I am really liking burnished burrs, which is on my sharpening video, and I talk a little about it on this one.

If by any chance you will get to Portland for the Symposium, I will have a double space with a lathe for demonstrating, and hopefully some hands on time as well.

robo hippy
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John Grace
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Re: Executing a push cut correctly...
Reply #17 - Nov 7th, 2017 at 7:43am
 
Ed Weber wrote on Nov 6th, 2017 at 7:57pm:
Primary grind is somewhere in the 57-60 range.Secondary grind is achieved by simply sliding the V-arm in towards the grinder about an inch and repeating.I prefer a U flute for this cut. A V flute is too aggressive and seems to have a smaller sweet spot when sweeping through a long transitional cut.


Ed...

If I understand correctly, your primary grind on this gouge is 57-60?

Is that angle specific to this tool for this cut or is that what you use on your bowl gouge in general?  I ask because I typically use a 40 degree grind.

With respects to the U-flute...are you using a 'bottom feeder' gouge or gouge with swept back wings?

Fantastic help, thanks...John
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Ed Weber
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Re: Executing a push cut correctly...
Reply #18 - Nov 7th, 2017 at 9:59am
 
John Grace wrote on Nov 7th, 2017 at 7:43am:
If I understand correctly, your primary grind on this gouge is 57-60?

Correct

John Grace wrote on Nov 7th, 2017 at 7:43am:
Is that angle specific to this tool for this cut or is that what you use on your bowl gouge in general?

This is the grind I settled on over the years as my "standard" bowl gouge grind. I had to go out to the shop and measure it since I never remember what it is. The grind is what some may call a type of  transition grind. I have noticed it is very similar to the Multimedia File Viewing and Clickable Links are available for Registered Members only!!  You need to Login or Register, who knew.

John Grace wrote on Nov 7th, 2017 at 7:43am:
With respects to the U-flute...are you using a 'bottom feeder' gouge or gouge with swept back wings?

For this type of cut I currently use a standard 1/2" Thompson U-flute. As you see in the photo the wings are not too long, wing length will change with flute shape. (when using the same grind) Wing length is approximately 5/8" for the U flute and 3/4" on the V flute. This works well for me since I use the wing for shear cutting. I don't have a parabolic fluted gouge yet (supposed to be good for this) but that may be my next gouge purchase.
Remember, this is just what works for me, also just about all brands of gouges have slightly different shaped flutes regardless of what they call them. not all U's are the same, etc..
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John Grace
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Re: Executing a push cut correctly...
Reply #19 - Nov 7th, 2017 at 5:50pm
 
Ed Weber wrote on Nov 7th, 2017 at 9:59am:
this is just what works for me,


Completely agree...appreciate the perspective.  thanks...
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John Grace
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Re: Executing a push cut correctly...
Reply #20 - Nov 7th, 2017 at 6:01pm
 
robo_hippy wrote on Nov 7th, 2017 at 1:57am:
My videos are old enough that I can't remember them well any more...

The 45/45 is the same as Stuart's 40/40, which he says can not be duplicated with a jig. So, platform at 45 degrees, and sweep and roll to the sides just past the mark/line which is at 40 degrees. He rolls it a bit past horizontal or level, I think anyway. I was mentoring and the student bought his gouges with him which were all jig ground, and to me, his wings were much more acute/pointy than mine. Stuart says his wing bevel is the same as the nose, which would make that true, but some thing I had not noticed.

The 'secondary' bevel is a strange concept to me because it is not a bevel that is used. I just round mine over free hand on the wheels rather than setting a separate angle, which takes too much time to me. The reason for this 'relief' is so that the cutting edge is closer to the bevel rubbing spot on the inside of a bowl or any convex surface. With a concave surface, there is no difference in the rub spot, no matter which bevel angle you use. I round over rather than second or third bevels to remove any sharp edge. Any sharp edge can and will leave marks.

Perhaps the most difficult skill I had to learn was the proper bevel rub, which is no pressure at all on it. Brute strength comes in handy on heavy scraper use for stock removal on bowls, but it is terrible for finish cuts. The lighter that bevel touch is, the smoother and cleaner your cuts are. Still working on perfecting this cut...

Next video out will be about shear scraping. The shooting is done and camera man is editing. I only use scrapers for this, and only V10 or M42HSS for my tools (Doug Thompson and Dave Schweitzer/ D Way tools). Far superior to M2HSS. I am really liking burnished burrs, which is on my sharpening video, and I talk a little about it on this one.

If by any chance you will get to Portland for the Symposium, I will have a double space with a lathe for demonstrating, and hopefully some hands on time as well.

robo hipp


Reed...I found this old post from you on the AAW site from several years ago...do you still concur with what you wrote?

I seldom use my swept back grind gouges any more. Maybe I should go back and try them some more. It is probably more due to my turning style rather than the 'usefulness' of the tool. I turn at the end of the lathe (sliding headstock). Most of my roughing is done with scrapers. I hold my tools level with little or no handle dropping. I prefer more open flute designs and really don't like the real V with a pointy bottom at all.

Why don't I use the swept back design? Well, the wings are the biggest difference, and work fine for a shear cut on the outside more than the inside with a dropped handle. With a level handle, you get the high shear angle with the nose, and do most of the cutting there rather than with the wings. I can do all the 'shear scrapes' with my scrapers, which just feel better to me. The wings have no advantage for my roughing cuts as the scrapers just out preform them. I can use any nose profile on my scrapers, but prefer the 'inside' scrapers, which if you look at them are swept back like 1/2 of a swept back gouge.

If you are going through convex and concave shapes on your bowls, a short bevel and a more blunt bevel angle will work better, and again, here I hold the tools level.

V flutes are used more for pull type cuts with the handle down, and the wing being the main cutting surface being used. The nose has a very small area for cutting, and for being held level, it is pretty much worthless for the cuts I use.

robo hippy
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Re: Executing a push cut correctly...
Reply #21 - Nov 7th, 2017 at 6:36pm
 
John

Like Jimmy Clues and lots of others say "Everyone has their own style". I had Lyle Jamison come to my house several times and he shown me how to do the Irish Grind and set up my grinder and Oneway grinding system to get it done.

I have never had a problem either pushing or pulling and leaving burnish marks on the wood but then I just let the tool do the cutting without pushing the tool hard into the wood.

Also like Jimmy Clues said they all have their own way and then sell their tools to those who think they need the tools to do a good cut.
He had me laughing at that because that is how I was until Lyle shown me how to use the bowl gouge and he also said for me to do 50+ bowls and then I would start learning how to do it right.  Also Lyle and Jimmy told me a lot of people try to do everything without doing one thing good and that was me also several years ago.   Grin

So it takes a lot of practice to do each project and take a lot of scrap wood to practice with.
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Re: Executing a push cut correctly...
Reply #22 - Nov 7th, 2017 at 9:29pm
 
Burnish marks or bruising usually only occur if you're pushing too hard and/or the curve is too tight . This is why where see people having trouble with the transition area of bowls. The heel of the tool can make contact and in turn, make the tip rise out of the cut. The "secondary bevel" isn't really a bevel but rather a relief cut (removing the heel) allowing the ability to have good bevel contact on tighter curves and with less potential for bruising.

Arlin Eastman wrote on Nov 7th, 2017 at 6:36pm:
Lyle shown me how to use the bowl gouge and he also said for me to do 50+ bowls and then I would start learning how to do it right.


Just as every piece of wood is different, so is every turner. Becoming competent or mastering a skill doesn't come from repetition.
Building skills comes from what you learn from each instance (bowl) and then how well you can apply what you've learned to the next until you are skilled enough that you no longer need "practice". It could take 50 bowls, it could take 100 bowls or it could take 10. Everyone is different.
JMO
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robo_hippy
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Re: Executing a push cut correctly...
Reply #23 - Nov 8th, 2017 at 10:51am
 
John, I still don't use the swept back gouges. No point to it, and I need to get a video clip up about that. The reasons are the same, all roughing and shear scraping with scrapers. Other than that, the only reason to use them is the nose angle. I don't like the 60 degree bevel for roughing or finish cuts on the sides of the bowl, I prefer the 45/45. My BOB tools all have ) shaped noses and 70 degree bevels. They get through the transition better that way with my style of turning. I do hold my tools more level when I cut.

I may correct myself on the V flutes. Some are more open than others. The more open ones will work fine with a swept back grind like the Doug Thompson V, and can do either push or pull well. The deep pointy V like the old Glaser tools, I just didn't like them no matter what I did with them.

robo hippy
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John Grace
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Re: Executing a push cut correctly...
Reply #24 - Nov 10th, 2017 at 1:56pm
 
Next question:  With the understanding that all of these terms have an inherit level of subjectivity...does anyone know if the Henry Taylor 'super-flute' gouge is their version of the parabolic flute?
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Ed Weber
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Re: Executing a push cut correctly...
Reply #25 - Nov 10th, 2017 at 2:03pm
 
It would appear to be yes

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John Grace
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Re: Executing a push cut correctly...
Reply #26 - Nov 10th, 2017 at 2:06pm
 
Ed Weber wrote on Nov 7th, 2017 at 9:59am:
This is the grind I settled on over the years as my "standard" bowl gouge grind.


Appreciate that we all have our own preferences but your comment has made me think of something.  When I switched from using carbides exclusively to predominantly traditional tools, I struggled with the grind angle question.  Basically...before I started experimenting with different grind angles as I see so many others do, I wanted to become reasonably competent at one commonly-used angle.  My thinking being that if I became competent at the one then I'd be able to judge the quality of my cuts and their 'safety' before beginning experimenting...minimizing the variables as it were.

Anyways, after much research, I settled on a 40 degree angle on my gouges and it's worked well.  Granted...that's on a relatively inexpensive gouge with a very deep v-groove.  Again...I being of the sort that wanted to become competent at my platform sharpening before $20 of Doug's steel ended up on the garage floor.

To all:  is there a common grind angle for executing the push cut or is it again left simply to personal preference?
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Ed Weber
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Re: Executing a push cut correctly...
Reply #27 - Nov 10th, 2017 at 5:24pm
 
John (and anyone else) here is a pdf that might help out some.
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Page 4 & 5 address a bit of what you're looking into.
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John Grace
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Re: Executing a push cut correctly...
Reply #28 - Nov 10th, 2017 at 7:02pm
 
WOW...thanks Ed, that is a wealth of information.  While reading it occurred to me that I have a 3/8 gouge that rarely if ever sees any action.  I think I just found my sacrificial testing tool.  If nothing else, based on the number of comments and reads it appears I did start an interesting thread.
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Ed Weber
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Re: Executing a push cut correctly...
Reply #29 - Nov 10th, 2017 at 7:23pm
 
John Grace wrote on Nov 10th, 2017 at 7:02pm:
If nothing else, based on the number of comments and reads it appears I did start an interesting thread.


Yes you did
It's good to make people stop and think about this type of thing now and then, it can often have some surprising outcomes. Many may not have given it much thought and simply performed it in a certain way out of habit. Often times people aren't aware that there may be a different, perhaps better way to approach it.

Good kuck with your testing, keep us posted
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