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Tool rest height??

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I just got an old lathe and the tool rest that came with it is too high. So I have to either cut the one down or get another. I have about 2" of movement to securely lock it down. So the question is what is the minimun height for a tool rest. I am suspecting at center height?
 

john lucas

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Rich Tool rest height is kind of a personal thing. You want to be cutting at or above center line for most cuts. I like to have the tool handle riding roughly on my hip so I place it there and then put the cutting edge about 10 to 11 oclock on the piece and then lock the tool rest down. The tool rest might actually be below center for this cut because you have to subtract the thickness of the tool. Turner height and lathe height also affect where the tool rest should be. A good example is when turners come over to use my lathe. I have the tool rest lower than they would because I'm shorter. We are still cutting at about the same place on the wood but because they are taller they have to raise the rest slightly or the tool handle will be on their thigh.
I also use what I call a pull cut for some things. For this cut I like the tool rest very low. I'm still cutting with the tool above center on the workpiece but the tool rest will sometimes be an inch lower than center line.
I also use the tool rest above center, sometimes quite a ways, when I turn beads on platters or my hand mirrors. I've found that I can roll a bead using the detail gouge in a similar fashion to the way I roll it on a spindle, if I have the tool rest really high.
The workpiece is round so tool rest height isn't critical, only the relationship between the tool fulcrum point of the tool and where the tool cuts on the wood. In other words if the tool rest is too high or low the fulcrum point is further from wood so you have more tool hanging over. This can be a problem. You can however get better control on some cuts with the tool rest higher or lower.
 
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tool rest hight

Rich,
Just came in for coffee and saw your post, so I went back out to measure. Not trying to not answer your question directly (what?) but here goes, (I have a PM3520) I dropped the stock tool rest in the banjo so it bottomed out, measuring up from the top of the rest to the point of the live center (my point of reference for centerline) is 1 1/8, then raised the rest so there was just enough to lock onto with the cinch handle (not sure what that thing’s called but you know what I mean) and measured from the top of the rest down to the point of the live center and got 1 5/8. Did the same with a Bestwoods rest and got the same number in the lowest position and got 2 1/8 fully raised. I don’t use either end of the extremes but this gives you some idea of travel you might look for…

cc
 
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Thol height sumation

Thanks John and Clif. I will set up like Clif indicated as I was looking for a range. So I appreciate the input.
Rich
 
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Obviously it should depend on your preferred turning style, not determine it. I like to cut with the rest close and the tool no more than ~20 degrees nose up. Keeps the load more on the rest than my arm, which is the way I like it. Good fulcrum is the key to tool control.

You want to be able to get below centerline to at least the center of the broadest gouge you use in my system, so that you can cut inside shapes like bowls without having the tool dig if you drop your arm a bit.

Places selling aftermarket rests usually have make and model matched to a good post length for you, so use their guidance as a beginning.
 

odie

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Something else some of you may want to consider....is making notches on your tool rest posts. Here, you see two notches on my tool rest posts.....one for centerline, and the other for maximum height. These reference points work for me, but you may wish to put the notches in other locations to match your own preferences and turning style.

The notches give you a visual reference of tool rest height every time you make an adjustment......I've found these notches to be extremely handy to have, takes the guesswork out of making height adjustments, and allows you to make them quicker.

otis of cologne
 

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Tool Rest Height

Rich,
Some friends of mine have cut some pvc pipe, of an appropriate diameter, and slip it on over the shaft of the tool rest before it goes into the banjo, and it is automatically at the height they prefer. Just an idea for you!
KurtB:)
 
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Shaft Collars are cheap and useful....

I prefer to use 1" ID shaft collars with added star-knobs (instead of the set screw) to set the height of my tool rests. These offer the ability to quickly return to the desired height as rests are switched-out, but also allows adjustment in small increments up and down to accommodate changing tools (different profile gouges, scrapers, parting tools, skews, etc.) which require me to adjust the height slightly as I turn. The shaft collars don't let the tool rest fall down when the screw on the banjo is released, so I can rotate the tool rest as needed and still be at the same height. This simple add-on is about the least expensive way to improve the tool rest (...other than the great idea of filing grooves on the shaft of the rest! - Thanks for that!)

Cheers,

Rob
 
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Not a "by the numbers," but a "good enough" turner, so take it for what it's worth. Back when I thought it was critical I used to keep a rubber O ring on the post of my rest so I could follow a contour in angles without changing height. Then I realized that I had quite a bit of angle to work with, as long as I observed the basic catch-prevention measures. The O ring which had been adjusted up and down for so long was not replaced when it failed.
 

john lucas

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MM I agree. I would find a collar of some kind useless. At least for me. I change the height of the rest constantly. My spindle gouges for example have different thicknesses so I use a slightly different height. When I switch to the skew I raise the tool rest a fair amount.
 
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"Try it... you'll like it..."

MM I agree. I would find a collar of some kind useless. At least for me. I change the height of the rest constantly. My spindle gouges for example have different thicknesses so I use a slightly different height. When I switch to the skew I raise the tool rest a fair amount.

John:

I thought the same thing about using shaft collars to maintain tool rest height until I started using them. Like you, I also change the position of the tool rest frequently, and because of the shaft collar (which also can be easily adjusted if you substitute a star-knob instead of the set screw), I can do one-handed repositioning of the tool rest without it crashing into the banjo when its tool rest locking screw is loosened. The tool rest stays at the same height as I rotate the rest and/or the banjo to get a better position for the rest relative to the surface being worked. The collars are also are useful to maintain a minimum rest height, so that when I need to raise the rest to accommodate different thicknes gouges, skews, scrapers, etc., I can visually get there quickly by seeing how much gap there is between the top of the banjo and the bottom of the shaft collar. I find that they are very useful, and have equipped most of my most frequently used tool rests with them. For under $3, they save me a bit of time and effort while turning..... I didn't "believe" until I tried it, and I find them to be useful and inexpensive additions to the tool rest & banjo part of the lathe; at least it works well for me.

YMMV...

Rob Wallace
 
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So you're saying it's easier for you to adjust two items than one?

I mostly move the banjo, but lucky for me I only have to back the post lock off a tad in order to be able to rotate when I wish the height to remain the same without doing so.
 
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I've found that different tools (which have different thicknesses, shapes, etc.) require different tool rest heights if I'm cutting at exactly the same spot when oval turning - and that's seriously required then. For round turning, sometimes I want to cut above and sometimes on the exact 90 degrees from vertical point. I've never had a good experience cutting wood below that point, but my tool rest is very often there as the tool and angle I'm holding it make the cutting point above it.

Going back and reading this barely makes sense to me, but I really don't know how better to write it.
 
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I suggest giving the rest the ability to drop about 1/2" below center. I'm going to contradict conventional wisdom, but my belief is... as you become more proficient on the lathe, the lower you are capable of turning in relation to the centerline of the turning, the better turner you will become, and the more possibilities you will discover. I usually turn right on the centerline, with the rest way below center. The flute of gouges is 90 degrees to the bed. I use the skew with a low rest as well, with either the toe up or down. Two very good reasons: first, I can easily turn down to small diameters without being a contortionist as the tool is always in the same plane. Two, catches, although rare, simply kick the tool into air, not deeper and deeper into the cut as with a higher rest. A skew can be used below center with the long point down and the bevel rubbing....lowering the handle raises the cutting edge, and gives controllable leverage for fast cutting of beads or spheres. Not for the faint of heart....it takes some practice to master this.
 
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marking spot

John:

I can visually get there quickly by seeing how much gap there is between the top of the banjo and the bottom of the shaft collar. I find that they are very useful, and have equipped most of my most frequently used tool rests with them. For under $3, they save me a bit of time and effort while turning..... I didn't "believe" until I tried it, and I find them to be useful and inexpensive additions to the tool rest & banjo part of the lathe; at least it works well for me.

YMMV...

Rob Wallace

I just use a magic marker line. If you wanted 2 lines, use a different color, Gretch
 
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It works for me -

So you're saying it's easier for you to adjust two items than one?

Yes, that's correct - especially when you can isolate one adjustment motion (rotation of the tool rest) from another (the height). When it is not necessary to adjust the height, I can reposition the tool rest with one hand by either: 1.) moving the banjo + tool rest assembly as one unit, or, when that won't be adequate, 2.) to loosen the tool post lock, rotate the tool rest to the needed position, and re-tighten the post. All of this within a few seconds, without stopping the lathe, and without putting down the tool that I'm using.

I mostly move the banjo, but lucky for me I only have to back the post lock off a tad in order to be able to rotate when I wish the height to remain the same without doing so.

Regardless of how slowly I 'back the post lock off' [...even a tad!] on my Jet 1642, an "un-collared" tool rest still crashes down to bottom-out in the banjo unless I'm holding it with the other hand. I suppose I'm just not lucky. :(

By having a collar on the tool rest post, it NEVER bottoms out, it keeps the proper height while I rotate it on the post axis to reposition it, and I can still proceed with my one-handed adjustments (using my left hand) of the tool rest much more efficiently than if I had to put down a tool and use two hands to make the adjustments. This little add-on saves me time.

So yes, MM, it IS easier to to adjust two items than one.

Rob
 
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When it is not necessary to adjust the height, I can reposition the tool rest with one hand by either: 1.) moving the banjo + tool rest assembly as one unit, or, when that won't be adequate, 2.) to loosen the tool post lock, rotate the tool rest to the needed position, and re-tighten the post. All of this within a few seconds, without stopping the lathe, and without putting down the tool that I'm using.

Road to perdition, that. I'd turn the lathe off. Not that I always do, but it's a smart thing.


Try a little corrosion on the post to fill the gaps for you. The Nova is notorious for having a tight fit. Your JET isn't like the old wedge-to-fit one on my Delta, I don't believe. It was nice to be able to use various diameter toolposts, but not the most positive lock in the world.
 
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John Lucas:

I just got my American Woodturner, and noticed the tip on using the thicknessed block of wood to set the height (repeatably) with the McNaughton System tool support......

This is another example of where a shaft collar would work perfectly - and does for me - I've been using one on my McNaughton hollowing system for well over a year. Instead of using a star knob with the collar like I do with my general tool rests, I just use the set ("grub") screw that comes with the collar, and leave it on the tool rest shaft all the time at the correct height setting.

A shaft collar would be more adjustable than a fixed thickness block of wood, particularly if you had to tweak the height setting a bit for differences in approach angle, etc.

See you in Richmond!

Rob Wallace
 
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Repeatable tool rest height with easy adjustment

I have been using heavy duty rubber o-rings on my tools rests to give me the ability to repeatably set the tool rest height. The most frequent adjustment I make is to rotate the rest, and having the o-ring in place lets that adjustment happen with one hand. To adjust the rest to be lower, only a gentle tap on the top of the request is required. Moving the tool rest up requires two hands because you need to roll the o-ring down the post.

Eventually the o-rings get loose and you can throw them away. My tool rest posts are 1", so I use 3/4" o-rings for a snug fit. Total cost to outfit all 6 of my tool rests was less than $1.00 spent at the local hardware store.
 

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