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Reversed grinder

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For years I have operated my grinder in reverse for sharpening lathe tools. I did this simply because I was advised to do it by a gentleman, whom I have a great deal of respect for, that was teaching me to turn and of course how to sharpen tools. The idea being that one could see the cutting edge making contact better this way. I have operated my grinder in this fashion since 1994 and have never run it as it was intended. To cut to the chase, does anyone else run their grinder in reverse? Am I out to lunch on this and missing something. Of all the videos that I have watched online, I don't see anyone operating a grinder in this fashion. Any thoughts or advise on this would be much appreciated.

Thanks
Rob
 
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I don't understand how operating in reverse would improve seeing the cutting edge making contact. In the "normal" rotation, the cutting edge makes contact when sparks spray over the edge toward you - ambiguous in reverse rotation, because the source of the sparks is hidden. Also, normal rotation mimics operation of the tool when cutting on the lathe. And allows the sharpening force to press the tool against the grinder's rest, same as the tool rest on the lathe; otherwise, you need to hold the tool down by hand against the grinder's tendency to lift it.

But if you've become comfortable (essentially trained your hand-eye coordination) that way, you'd have a new learning curve to climb if you convert to "normal" operation. If you can try the "normal" way on another grinder, you might see its advantages. Or not.
 
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Really makes little difference with modern stones. On the negative side, if you grind away, especially with softer stones, you build up trash behind and under the grind rather than lifting it off. On the positive, you can get a wet shirt if you use a wet whet grinding toward yourself, which supports grinding away.

I strop running away on my carving tools because of roundover problems, and it works fine.
 

john lucas

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Wood carvers who use sanding belts us the belt traveling away from the cut technique. I'm not sure about knife sanders. I thought they ran down but will have to call my friend and find out.
The way I look at it seems that I have more control because the lower shoulder of my bevel acts like a fulcrum and lets me rock the tool into the cut and then keep it there. With the stone turning up is sort of want to pull the tool away from the cut. I've only tried this on my hand cranked grinder (see the video in the techniques section on truing grinding wheels) but it seems easier to control.
I'll be interested in what others have to say. Not seeing the sparks is why I don't like using the wet wheel grinders. When I hand sharpen without a jig I cannot see the sparks so it's kind of like guessing when the edge is really sharp. Maybe I'm just old school. Or maybe I'm just old. :)
 
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John,

My knifemaking buddy did everything on his big belt machine towards him.

It's been a long time since I was over there piddling, but that's what I remember.

Rich
 
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Scraper specific

When grinding a scraper whereby I am trying to obtain a burr for traditional scraping I do get a nice edge with the reversed rotation. That being said I don't often use a scraper because I have never been able to use it with any great success. Now I am considering trying to shear cut with a scraper and I understand that I should not have this burr. Will I get less burr grinding with the normal rotation. I have to hone it off regardless I suppose.
 
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I would think that this is one of those "it works for him" situations. Can't say I ever heard of any one else doing it that way. I think there would be a bigger burr that way, and not as strong as a burr from grinding normal way. I use scrapers a lot, and prefer the burr straight from my grinder. Good for roughing, and shear cutting. A burnished burr works a bit better. Can't imagine shear cuts without a burr, though you could do a bevel rubbing cut that would work.

robo hippy
 

john lucas

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I'll have to try it again but one time I turned my scraper over and ground upside down thinking it would produce a better burr. It didn't as I remember but that was along time ago. If I want control of the burr I use diamond hones. I polish off the top and then create the burr by running the hone up the tool. Medium hones produce a nice burr, fine and ultra fine produce smaller burrs.
I do believe you need a burr for shear scraping. I find the ceramic hone that John Jordan sells produces a very nice burr on his scraper. I used to use the diamond hones but once I tried the ceramic hone on his tool that's all I use. I have 2 flat scrapers. One is a Sorby the other is handmade by me. My homemade one works better with the medium diamond hone. The sorby works great right off the 100 grit grinding wheel.
 
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Alrighty then! Having read your input and done a lot of surfing today, I am going to do two things. First I'll reverse the grinder and second ensure I have a burr, honed or otherwise on any scraper. The next thing is, should I make a move toward dedicated shear scrapers? I'm wide open to suggestions and respectful of all opinions.

P.S. I will remind my wife our 40th wedding anniversary is (of all dates) 9 11.

Rob
 
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The next thing is, should I make a move toward dedicated shear scrapers? I'm wide open to suggestions and respectful of all opinions.

P.S. I will remind my wife our 40th wedding anniversary is (of all dates) 9 11.

Rob

Why scrape if you can cut? Get a broad sweep gouge or two and do like this.

http://s108.photobucket.com/albums/n28/MichaelMouse/?action=view&current=35mmGougeRounding.mp4

http://s108.photobucket.com/albums/n28/MichaelMouse/?action=view&current=CherryPeelIn.mp4

It's "shear scraping" with benefits. No burr or turned edge required.
 

john lucas

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Well I do cut. But you know sometimes it doesn't come out perfect. There may be a little bump you feel but don't see on the outside that ruins a perfect curve. I can take that down very accurately by shear scraping. Or there may be some minor tearout or grain that just doesn't want to cut cleanly. This is especially true on really green bowls with twisted grain. I switch to the shear scraper and clean that up.
In the hands of someone who doesn't use the cutting tools as well I do it can be a lifesaver.
for me it just cuts out a grit or two of sandpaper. I turn my hand mirrors and right off the tool they are pretty clean. I still make one light pass with the shear scraper. It refines the finish so I start sanding with 220. Starting with that grit I don't ruin any of the fine details or shapes like I would with lower grits.
I still strive to get the best finish I can right off the tool but I'm not perfect, yet. Working at it but still have long way to go.
 
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Do you have the proper tools to do it, John, or are you trying to make another tool do what the broad sweep does so effortlessly? Referencing where it's been to help where it's going keeps those ridges away. You have to sweep to keep away the wide undulations. Your roll angle, in combination with your skew, makes a uniform thickness shaving possible, because the tool cuts progressively deeper.

Any tool can scrape. So when the transition's made to the bottom of the inside, the radius of the nose, not the gouge, takes over. Same as your shear scraping.
 

john lucas

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MM I have a lot of different tools and I'm always willing to play with new techniques. I've studied the cuts or guys like Stewart Batty and John Jordan who are really good at using the tools. I think I do pretty good based on turned pieces that are passed around at demos. However I'm pretty picky and find a scraper is a good tool to really refine the shape when necessary.
I'm not talking about having to remove large tool marks or obvious tearout. This is very subtle stuff I'm correcting.
I have large spindle gouges and have even used the skew on the outside of bowls. I do that just to learn how tools cut and what works. Right now my favorite gouge and technique is the Stewart Batty 45 degree grind. for bowls it is a really clean cut.
 
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So the answer's no. Highly recommend the broad sweep ground at a constant angle. Nothing new, sadly, but works a treat.
 

john lucas

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Well actually I think my skills are up there with the better turners. Not the best. I practice a lot and most people would think what i get is an excellent finish right off the tool. I'm just sort of a perfectionist and I'm always trying to improve.
As I mentioned I have use broad tipped gouges, including your favorite the roughing gouge. Broad tipped gouges can pull out swirly grain where a narrow tip gouge won't. I haven't figured out why that's true because both of my tools have the same grind angle. Every now and then I'll be cutting an area with a knot or swirly grain and no matter which direction I cut from it lifts the grain in a couple of spots. I can switch to a gouge with a smaller tip and it will go away. That's' why I like the Stewart Batty 45 degree grind on a 1/2" gouge. It seems to have the best of both worlds.
I've been experimenting with the Michelson (hope I didn't spell that wrong) grind. It is a convex grind and has a much narrower tip. It excells at turning thin and not catching. It's also good for the swirly grain patches I mentioned above and seems to be better on bowls where your turning lots of air. I have a little trouble sharpening it consistently so I feel like I'm searching for the cut each time I come back from the grinder.
 
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Michael
I checked out the particular videos in Photobucket you had links for and while there looked at all the others (12 total). It is difficult to see the gouge in the video,though I can see they seem to cut nicely. The only Sorby gouge that I can find that is 35 mm is the what they call the Continental style gouge ranging in size from 8 to 35 mm. Are these the broad sweep gouges you are talking about. If so, what is different about these than a roughing gouge? They don't look like a spindle gouge and they are fairly deep by the look of them in the Sorby catalogue.

Rob
 
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The 35 is a modified roughing type, similar to what the old birds used for inside work. As you can see, there are no corners to catch, but the size is still a barrier inside of things.

Since ANY gouge of the "continental" or "European" /forged type has uniform thickness, they're more or less the same in application. They are ground at the same angle across, with a modest rounding of the nose as a result of taking the corners off. The trio from Lee Valley as I grind them here. http://i35.photobucket.com/albums/d160/GoodOnesGone/Three-Noses.jpg Nose on the smallest is not quite as pronounced now, but you can see it and one of my old HSS types sharpened here. http://i35.photobucket.com/albums/d160/GoodOnesGone/Bevels.jpg I use the edge of the small gouges for entry rather than the curve of the nose, as with the larger. It still presents much less section for initial penetration, which keeps the gouge from "kicking back" over the rim. Once the tool is rotated into the work the transition to skewed and shear is accomplished simultaneously. The big gouges will make shavings 3/4" wide if you have wet wood, so they make short work of roughing, while making great smoothers when the shaving's a quarter or less wide due to a smaller shear.
 
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Hi Rob,

I've a Tormek wet grinder and it runs in reverse just like any Tormek.

I think the only disadvantage with this, that I know of, is the freehand sharpening.

For example I'm having lots of difficulties sharpening Alan Lacer Skew on Tormek. The problem is, the skew tends to run away from me, whereas in high-speed grinders you pretty much maintain control over the contact of the tool with the grinder (if the grinding wheel is turning towards me, then by contacting the tool against the grinding wheel I can decide to push the tool or pull it back.)

Does anyone else experience this problem---that is, sharpening Lacer's Skew on a Tormek.

Cheers,
Jake
 

john lucas

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I have the Sheppac wet grinder which is similar to the Jet, GRiz, and Tormek. I do not like hand sharpening on it. If I use a jig it's great although I tend to use it for carving tools and flat chisels, not turning tools. I have tried sharpening the skew on it and ran into the same problem you have.
 
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Jake,
I have a Tormek and while I don't use it much except for carving tools and my wife's good knives, etc, I'm not sure what you mean when you have issues with the Alan Lacer skew? When you say running away, what direction does the skew want to go? Are you behind the machine and on top or are you in front of the machine? I'm assuming you are talking about the large skew. This tool as with most skews is best kept very sharp. I use a diamond hone on my so it doesn't see the wheel that much. I just switched from the ceramic SG Norton stone to a CBN wheel, this is one of the best investments I've made. Very smooth and wider than the stone wheel. Now we'll see how long it lasts. But back to your comment as slow as the wheel turns I'm surprised it's giving you any issues. Have you tried it from the front like a regular grinder so the wheel is coming into the blade? That would put a bit of water everywhere but should stop the skew from trying to move out of your hand.
 
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Thanks for the tips on CBN wheel.

In regards to Lacer's large skew, I sharpen it from the front. So the stone is on my right hand side and the honing wheel is on the left.

I've also tried sharpening the other way around--that is holding the tool from the top-down and in that case the sharpening stone is on my left hand side.

The latter one seems to work fine, however it's a bit uncomfortable--mainly because the Tormek is sitting on a 36" counter height, and it becomes a bit harder to move the tool nicely and evenly.

But, just like you, I quickly realized that it's better to put some effort and use hand sharpening. Honestly, I loved the hand sharpening (it feels like you're taking care of the tool very very specially!)

Cheers,
Jake
 
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Jake,
I just switched from the ceramic SG Norton stone to a CBN wheel, this is one of the best investments I've made. Very smooth and wider than the stone wheel. Now we'll see how long it lasts.
Could someone explain to us dumbies what a CBN wheel is?

Thanks.

Dean Center
 
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CBN (Cubic Boron Nitride) grinding wheels are not very common in many woodworking shops. It's pretty much equal to a diamond wheel, but it's not diamond (duh) :) it's synthetic, chemical stuff that is as strong as a diamond wheel (or maybe just, pretty long lasting stuff that wont explode on your face)

Anyhow, I've a small piece of a CBN stick (not a wheel) that I use to sharpen the dovetailing machine cutter in my shop. It sharpens the bevel really fast, just couple of passes makes the dull edge shine.

By the way, I'd love to see a video on how CBN wheel works with the HSS gouges. Thanks in advance!

Cheers,
Jake
 
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Most of the tools I use on a daily basis are from Doug Thompson. The others are Hamlet and Glaser/HiTec. Very smooth and easy in one or two passes. If it holds up, best thing since sliced bread. I have been very frustrated by the Norton SG wheel, I'm sure it is just the one I got.
 
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