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Forum topic by trz posted 557 days ago 794 views 0 times favorited 16 replies Add to Favorites Watch
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trz

65 posts in 1084 days


557 days ago

looking at some basic woodturning instructions and read for spindle turning to have the tool rest slightly below the center line of the turning blank. But, my instruction manual for the lathe says to position the rest about an eighth of an inch above the centerline. What gives?


16 replies so far

View rum's profile

rum

148 posts in 1184 days


#1 posted 557 days ago

It really depends on the tool and the work. Bigger tools need the rest slightly lower because they are thicker and thus the cutting edge is higher than a smaller tool would be with the rest at the same height. Some tools also work a smidge better with with the rest higher, I prefer to have the rest maybe 1/8 or so higher (haven’t actually measured it..) with the skew than I do with a roughing gouge (for instance).

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Loren

7231 posts in 2246 days


#2 posted 557 days ago

I put it a little below the centerline personally.

-- http://lawoodworking.com

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David Kirtley

1276 posts in 1596 days


#3 posted 557 days ago

The tool rest height is not a set dimension. You could have the tool rest anywhere and it wouldn’t matter as far as the cutting action. It depends on how you are holding the tool, the cutting edge, and the relief on the back side of the cutter (bevel).

The cutting angle will be from about 90 degrees for a scraper (actually you can use a negative rake for some materials such as brass) to down as low as 20 degrees for a skew. You then adjust the tool rest height to what is comfortable to you to achieve this angle. If you are tall or the lathe is on a low stand, it will probably be more comfortable to have the tool rest higher. The opposite if you are shorter or the lathe is higher. You can also adjust for the the tool you use the most since you will be holding it for the longest time. If you are mostly turning spindles with thicker shank gouges, you probably will want it a little lower and higher if you mostly use a skew.

-- Woodworking shouldn't cost a fortune: http://lowbudgetwoodworker.blogspot.com/

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trz

65 posts in 1084 days


#4 posted 557 days ago

thanks, that helps. I won’t worry about it now. I’ll go with what works best for me.

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Jimbo4

1121 posts in 1361 days


#5 posted 557 days ago

I set my tool rest with the tool level on the center line of what I am going to turn. Exception: For scrapers I set the rest slightly above so the tool is at a slight nose down angle of the center.

-- BELT SANDER: Used for making rectangular gouges in wood.

View MonteCristo's profile

MonteCristo

2094 posts in 786 days


#6 posted 557 days ago

You could have the tool rest anywhere and it wouldn’t matter as far as the cutting action.

I rather doubt the likes of Richard Raffan or Mike Darlow would recommend this line of thinking. Inappropriate tool rest height and the subsequent holding of a tool at an odd-ball angle sounds like a recipe for disaster to me.

Darlow treats wood turning like a science. His books will give you tons of info on this sort of thing and explain in gory detail why it results in good and safe turning. Check him out.

-- Dwight - "Free legal advice available - contact Dewey, Cheetam & Howe""

View David Kirtley's profile

David Kirtley

1276 posts in 1596 days


#7 posted 557 days ago

Hi Dwight. I think you must have misinterpreted my response. Let me explain it a bit more carefully.

Telling someone that they must have their tool rest at a certain height is explicitly “a recipe for disaster.” That the whole point of an adjustable height tool rest. You set the tool where it is comfortable and in control and presents the cutting edge at the proper angle so you can feed directly towards the center of rotation (most times) and not hold the tool at an “odd-ball angle.” It is basic physics and geometry. It depends on the material being cut, the angle the tool is presented to the work, the thickness of the tool, the alloy of the cutting tool (as in carbon steel tools as opposed to HSS or carbide) , and the distance from the stock and the the rest.

There is no one height that is universal. It changes depending on what you are doing. If you are using a skew, you probably should raise it because you cut above the centerline with a skew and you use the lower edge of the tool and not the point. If you are using a scraper, lower it because the cutting edge is at the top of the tool and not in the middle. If you are using a parting tool, you lower it to where the cutting edge is exactly on center and you are feeding horizontally so you can make sure to stay on center. Some parting tools cut at the top of the blade, some cut at the middle. You may be over height with a gouge so you can use the bevel to limit your depth of cut. Sometimes you have to put it at the wrong height because you have a section where the steady rest can not go close enough to the work and you adjust the height so you can put the tool handle in a better position for gaining leverage or hand position to compensate. This can really happen when doing hollow form turning. This also changes depending on your height relative to the centerline of the lathe.

There are multiple directions that a tool can feed into the workpiece. All that matters is that the tool’s cutting edge is presented at the proper cutting angle and on center from the direction it is being fed and it is rigidly held. Slant bed lathes have the tool coming in from what would be to top of the lathe on a standard wood turning lathe. It is quite commonplace on metal lathes to put a parting tool off on the back side of the lathe with the tool upside down. Many CNC lathes have multiple tools coming in from different directions to be able to switch tools quickly. You may also present the tool in different orientations to simplify the geometry of the grind of cutting tools. You often bore on the other side with the tool upside down so you can see what you are cutting.

-- Woodworking shouldn't cost a fortune: http://lowbudgetwoodworker.blogspot.com/

View Jimbo4's profile

Jimbo4

1121 posts in 1361 days


#8 posted 556 days ago

David: Your explanation is exactly what mine is – only a whole lot longer. Put the rest you want it, as long as it is comfortable. However: don’t get weird with the angles – CATCH TIME !

-- BELT SANDER: Used for making rectangular gouges in wood.

View MonteCristo's profile

MonteCristo

2094 posts in 786 days


#9 posted 556 days ago

I think we are all saying the same thing. But I think it’s a good idea to be careful how one phrases things with beginners . . . David obviously has heaps of experience but TRZ needs to hear just the basics for now . . .

-- Dwight - "Free legal advice available - contact Dewey, Cheetam & Howe""

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SCOTSMAN

5243 posts in 2183 days


#10 posted 556 days ago

If you have the toolrest too low or too high you may get dig ins I suggest you start thinking about the tool height as opposed to the toolrest height. I like my toolheight on centre and scrapers must be above centre with the handle high and the tool cutting edge lower than the handle. For other turning the handle is set lower than the cutting edge and the tool handle raised to bring in the shoulder, then bevel edge, then raised a bit more to start cutting as the cutting edge makes finally contact cuts,Simply lower it if your taking too deep a cut and reverse if the cut is too mild or shallow.As said scrapers the handle higher than the tool edge and others as stated here.At least this is what I have been taught and practice for safety and efficiency. Alistair

-- excuse my typing as I have a form of parkinsons disease

View rum's profile

rum

148 posts in 1184 days


#11 posted 556 days ago

Yep! A good way to try this is to set your tool rest and then with the lathe off try taking a shaving off with whatever tool you’re using. If you can cleanly do that in slow motion you are at least close to right region (for a scraper you may need to hand rotate the work, but for a gouge or a skew you should be able to mostly just slide it along the rest parallel to the work and have a shaving appear).

View trz's profile

trz

65 posts in 1084 days


#12 posted 556 days ago

Got that right Monte. thanks for everyones help. This is all new to me and I haven’t had a chance to put a tool to the wood yet. So, wish me luck .

View Roper's profile

Roper

1346 posts in 2311 days


#13 posted 555 days ago

I recommend taking a woodturning class from someone who can show you the proper way to setup and use your lathe and tools. Don’t just “Try stuff” that can be very dangerous.

-- Roper - Master of sawdust- www.roperwoodturning.com

View Dan's profile

Dan

150 posts in 557 days


#14 posted 551 days ago

Just a safety note from someone who learned the hard way. (As much as I hate to publicly admit to stupidity lol)

I am always as safety conscience as I can be when it comes to power tools. When using your lathe be sure to pay 100% attention to what your doing and where your tool is 100% of the time. Even as careful as I am, just a short while ago I looked away from my project for less than 2 seconds and my reward was a purple and black thumb. In that quick moment the piece broke at its thin point (was turning one area pretty thin) and the larger chuck flew into the tip of my thumb. Although nothing was broken, the tip of my thumb was dark purple for days.

I know some people will get a chuckle out of this, but I think most will take an important safety lesson from it.

-- Dan - Wooden Treasures CT - http://woodentreasuresct.etsy.com http://www.youtube.com/woodentreasuresct

View Underdog's profile

Underdog

501 posts in 633 days


#15 posted 551 days ago

Welcome to the Vortex.

Here’s my advice in addition to the good advice you’re received above. Wear a face shield. Get a good one like a Uvex Bionix. Wear it. It’ll save your face.

Join a woodturning club. The AAW has a site that lists turning clubs all over the US with their location, contact info and meeting dates. These guys will be all too happy to assist you in whatever manner you need. When I joined the Classic City Woodturners, I received instruction, encouragement, wood, tools, and lots of friends.

I would learn the difference between cutting and scraping too. It’s not enough to “stick the pointy end” into the wood. One must learn how to make a clean cut when using gouges and skews. One can get a clean cut with a scraping tool as well, but it is a totally different approach. When tools are applied incorrectly you can have a catch, break a tool, and/or get moderately or severely injured.

If you like books, I can think of no better starting place than Keith Rowley's book Woodturning: A Foundation Course. I think it now comes with a DVD. If you like videos, there are a gazillion YouTube videos on the web, and I’ll bet there are a few the deal with proper tool approach. There is still no substitute for some hand’s on instruction, and for that I recommend a club.

The ABCs of cutting (not scraping): Anchor the tool on the tool rest. Failure to do so will result in the tool being slammed down by the spinning wood as the tool digs in.
Slowly lower the Bevel of the tool to the spinning wood at an angle such that the cutting edge almost engages.
Then as you raise the handle, engage the Cutting edge until you see ribbons of wood coming across the top of the tool.

This is an extremely addictive hobby, and it’s a lot of fun.

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