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Old 07-08-2018, 10:45 PM   #11 (permalink)
 
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TC, you do not say what size skew you are using or I missed it. But the smaller the skew the more chance of heal or toe of tool will catch. Happens alot with 1/2" skews or miniature tools.

Usually with pens the diameter of the cylinder is very small so catches should be rare. I keep the tool rest below center enough so that when I present tool to project it is at center for cutting but the butt end of the tool is well below center. I lift the back of the tool to start cutting. Rub the bevel and start lifting and if tool is sharp it will cut nicely. In other words I am angling up not straight across. I cut with the center of the tool. I found if I keep tool in line with blank it can push forward and grab and thus chip outs. Keep tool steady at all times and do not let it roll one way or other. Straight across with your body following the cut not just your hands. Doing it my way the shearing is less stressful. But again being able to control the tool with both hands is key. You need to be able to ride your finger along the tool rest and the top of the tool rest can not have nicks and gouges in it or the skew will tilt on you when you hit them. Need to watch some videos of others doing this and then practice.

http://jimscarsella.com/uploads/3/4/...aw_article.pdf


how to make a shearing cut with a skew chisel - Bing video
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Old 07-08-2018, 11:20 PM   #12 (permalink)
 
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Quote:
Originally Posted by JimB View Post
My guess is one of the corners, the heel or toe, is catching. It is most likely the one leading. When using a normal scraper, or a negative rake scraper the corners are slightly curved to avoid this. This is true even on a flat nose scraper as they are not really ground flat across but rather with a very slight curve. If your skew is flat across there is a good chance of the leading corner catching.
Jim you are most likely right but I am very careful to not present that leading edge so it's frustrating that despite all the caution I still get the result I got yesterday. I found a youtube video of the cut I'm trying to make. The IAP is also referenced in this video so it could be one of our members. Take a look at https://www.youtube.com/watch?v=bAY8phk4Uh4 and in particular at 3:06 mins. There's also an interesting cut at 3:21 where the skew is going in reverse, some type of shearing cut, I have used similar with a gouge.
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Old 07-09-2018, 03:19 AM   #13 (permalink)
 
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I also use my 3/4" skew on its side to take a CA finish that is too thick down to a closer size ready for sanding. I find I get the best results with the skew freshly sharpened straight off the grinder, when it has been touched up with the fine diamond lap, it doesn't seem to work as well for this job. I think the grinder might leave a more jagged edge at microscopic level which helps to cut/scrape the CA with less pressure, or perhaps it does leave a slight burr, once touched up with the diamond lap, it refines the edge too much and it loses whatever the edge straight off the grinder has.
I don't have to resort to the skew very often, as I take my blanks down to 0.1 - 0.2mm (.004" -.008" )undersize, and as I am putting the coats of CA on, I measure with my callipers, to build up the finish to no more than 0.2mm ( .008" ) oversize, which can be sanded down to size fairly quickly with fresh 400 W&D.
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Old 07-09-2018, 07:57 AM   #14 (permalink)
 
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Simply wonderful,controlled finishing can be achieved using a reverse angle or negative rake scraper ground to 35 degrees and cut back at 60 or 70 degrees,ever able to give gentle correction to a finish preparation you seek.

Peter.
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Old 07-09-2018, 03:21 PM   #15 (permalink)
 
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We don't have a scraper at the center for the blind and use a little half inch skew to do exactly what you are describing. I put the rest as close as i can get it and at such a height that the blade of the skew is at the middle of the blank. Holding the skew absolutely level, as though it were a carbide tool, you can plane out tool marks from the pen blank, swinging the handle as needed to follow the shape of the pen. We also use it for shaping beads. I make a V cut with the tip of the skew then place it flat on the rest and swing the handle until the point of the skew goes into the V cut. Turn it over and swing it the other way. This is the most fool proof way I've found for my blind turners to shape beads.

Mark observed us using a skew this way when he was here last week.
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Old 07-09-2018, 07:37 PM   #16 (permalink)
 
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I can think of four possible ways to use the skew.

One is with the handle down, the tool rotated axially so that just one long corner is resting on the tool rest, the bevel rubbing on the wood, the long point above the short point, the cutting edge at a 45 deg angle to the lathe axis, and cutting occurring at or close to the short point. (Really difficult to try to explain)

A second is with the tool more horizontal, the long point down and the short point up, bevel rubbing, cutting occurs at or close to the long point, and the cutting edge is moving towards the headstock or tailstock.

A third is what I have read is a peeling cut - bevel rubbing, the cutting edge is parallel to the axis of the lathe.

The fourth would be a scrape, with the tool essentially horizontal.

I'm not clear which of these four describe how you are trying to use the skew, and I think some of the responses are in terms of one of these uses and some responses in terms of another.
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Old 07-09-2018, 07:55 PM   #17 (permalink)
 
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Quote:
Originally Posted by jttheclockman View Post
TC, you do not say what size skew you are using or I missed it. But the smaller the skew the more chance of heal or toe of tool will catch. Happens alot with 1/2" skews or miniature tools.

Usually with pens the diameter of the cylinder is very small so catches should be rare. I keep the tool rest below center enough so that when I present tool to project it is at center for cutting but the butt end of the tool is well below center. I lift the back of the tool to start cutting. Rub the bevel and start lifting and if tool is sharp it will cut nicely. In other words I am angling up not straight across. I cut with the center of the tool. I found if I keep tool in line with blank it can push forward and grab and thus chip outs. Keep tool steady at all times and do not let it roll one way or other. Straight across with your body following the cut not just your hands. Doing it my way the shearing is less stressful. But again being able to control the tool with both hands is key. You need to be able to ride your finger along the tool rest and the top of the tool rest can not have nicks and gouges in it or the skew will tilt on you when you hit them. Need to watch some videos of others doing this and then practice.

http://jimscarsella.com/uploads/3/4/...aw_article.pdf


how to make a shearing cut with a skew chisel - Bing video
JT, I use a 1 inch skew and a 1/2 inch skew. I don't get catches when I use it in a planing mode, only when I use it in light scraping mode.
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Old 07-09-2018, 07:57 PM   #18 (permalink)
 
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Quote:
Originally Posted by PenPal View Post
Simply wonderful,controlled finishing can be achieved using a reverse angle or negative rake scraper ground to 35 degrees and cut back at 60 or 70 degrees,ever able to give gentle correction to a finish preparation you seek.

Peter.
Controlled finishing is exactly what I'm trying to achieve but rather than have a dedicated scraper I like to do this with a skew if possible.
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Old 07-09-2018, 07:58 PM   #19 (permalink)
 
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Quote:
Originally Posted by sbwertz View Post
We don't have a scraper at the center for the blind and use a little half inch skew to do exactly what you are describing. I put the rest as close as i can get it and at such a height that the blade of the skew is at the middle of the blank. Holding the skew absolutely level, as though it were a carbide tool, you can plane out tool marks from the pen blank, swinging the handle as needed to follow the shape of the pen. We also use it for shaping beads. I make a V cut with the tip of the skew then place it flat on the rest and swing the handle until the point of the skew goes into the V cut. Turn it over and swing it the other way. This is the most fool proof way I've found for my blind turners to shape beads.

Mark observed us using a skew this way when he was here last week.
Hi Sharon, do you put a radius on that skew or is it a straight grind?
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Old 07-09-2018, 08:00 PM   #20 (permalink)
 
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Quote:
Originally Posted by donstephan View Post
I can think of four possible ways to use the skew.

One is with the handle down, the tool rotated axially so that just one long corner is resting on the tool rest, the bevel rubbing on the wood, the long point above the short point, the cutting edge at a 45 deg angle to the lathe axis, and cutting occurring at or close to the short point. (Really difficult to try to explain)

A second is with the tool more horizontal, the long point down and the short point up, bevel rubbing, cutting occurs at or close to the long point, and the cutting edge is moving towards the headstock or tailstock.

A third is what I have read is a peeling cut - bevel rubbing, the cutting edge is parallel to the axis of the lathe.

The fourth would be a scrape, with the tool essentially horizontal.

I'm not clear which of these four describe how you are trying to use the skew, and I think some of the responses are in terms of one of these uses and some responses in terms of another.
Truly versatile, I am interested/troubled by number 4, I'm trying to work out why I have catches/chipout with possibly the least complicated skew technique.
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