To my fellow woodturners,
Being part Einstein and another part Edison, and another part Elvis <biggrin>I got this idea about making a lathe tool for reaching in and undercutting bowl and vessel rims. The pros call this “hollow form” turning. like the excellent work David Ellsworth is known for. Tool catalogs sell various types of turning chisels for this task but none seemed to fit my fancy or pocketbook. Anyway. I bought a 3/4 inch diameter round boring bar and 20 different 1/4 inch carbide bits (tooling actually meant for metal lathes) from Grizzly for $40 total and after I make a handle for the boring bar I will share my experiences with all. Who knows? Maybe I can sell this tool idea and make a fortune, ha.
Just curious, has anyone else adapted metal lathe functions to wood turning? My next idea is to somehow make a tool holder like the turrets on metal lathes. A holder that would fit on my wood lathe and operate with simple turns of handwheels rather than force of hand and arm. With the sort of huge bowls I often turn, such an operation would sure reduce the jarring knocks of bringing a new turning blank to round.
sawick
Replies
That's kind of a neat concept.
I have just started making some tools for this and that on the lathe find that there is a shortage of tools for miniatutre turnings. I am just making a 2mm beading tool from piece of 4mm flat stock.(hollow grinding the tip to get consistency of bead.
I have plans to make a couple of 3/4" bowl gouges soon as I can borrow a forge for a few minutes to rough out the gouge.
I am learning to use a duplicator and have made 4 tools for it in the past 3 weeks each one adding more possiblilities to projects.
When you spoke of turret mounted tools for initial rounding I was reminded that this is one of the advantages of the dupilcator.
I can take even minimal passes over stock wihout much excitement or fatigue.
Maybe a duplicator is in your future.
Hey 4333: thought people were born duplicators, nyuk nyuk
Ray
Some are some aren't .
I personally had the unfortunate experience of being born a lover instead of a duplicator.
I learned duplication as an extention of my real self.
So far it's just me and mini me!
4333,
I don't see a real need for a duplicator now as most of my work is "one of a kind" or kinda artistic turning. However, I am always trying to make a hard job easier and thought a change in tooling might help. Fun just to putter around with ideas though. Trouble is, metal working is not my forte.
sawick
Go to any Pattern Shop and you will find thier lathe has a compound the same as a metal lathe. One thing to remember though is with this setup almost all your tooling will be scrapers if that makes a difference to you.
Rich
The Professional Termite
Trialnut,
Scraping is not necessarily a problem since the wood I use for turning rarely lends itself to fine gouge work. I make freeform bowls out of many woods usually found in firewood piles and so forth. Therefore, this stock is pretty nasty to begin with and requires beaucoup sanding anyway. With my idea however, I thought the carbide tips from the metal lathe cutters would stay sharp longer than my current tools. I make my own lathe tools usually out of old files. They hold an edge reasonably long depending on the type of wood I'm turning.
sawick
sawick
Rather than using the carbide tools use high speed steel. For wood turning it will hold up plenty well enough without the hassels of carbide. You will be able to grind the profile you want out of HSS much quicker and be able to grind to sharper points. Use a white or pink wheel for HSS. We turn all day with one sharpening unless we hit a screw.<g> Also with HSS you will be able to make smaller cutters cause you dont need a seperate shank to hold a brazed on tip. We have a drawer full of carbide tooling and never use any of it. Most of our turning is done with a 3/8 HSS bit sharpened to a diamond point and it leaves a surface we dont need to sand.
Good luck
RichThe Professional Termite
Trialnut,
Now ya tell me!! And after I already bought all that carbide!! I agree that HSS makes more effective tools with all traits considered. However, I guess I felt compelled to experiment. I always was one to learn the hard way. No Need for brazed cutters though in my new experiment. The metal lathe boring bar holds the carbide cutters via a set screw. Further, the boring bar offers a cutter set at 90 or 45 which I hope will give some sideways versatility for hollow form cutting, especially in relatively flat work such as shallow bowls and trays.
You say you turn all day with one sharpening? What stock are you using; oleo margarine? <g>. I tend to sharpen 4 or 5 tools and they will be dull quickly into the job. That is primarily due to the fact that I sharpen only on the grinder on a 120 grit wheel then go straight to the bowl. I am in the process of changing this primitive approach however. I am slowly constructing a full sharpening setup complete with a 320 grit white stone and honing wheel.. If I ever get this multi tasking setup done I sure hope my turning capacities will increase and improve.
BTW, what approaches do you use for sanding?
sawick
sawick
The carbide inserts are an OK way to go as long as you can get the profile you want. We do use then some. Gives you new sharp edges without losing any stops that are set. We turn mostly Sugar Pine and Mahogany. Neither one is very abrasive to cutters. We also go straight from the grinder to the wood. 100 or 120 grit wheel, can't remember which. We had one guy who used to hone the tools but his sharpenings didn't last any longer and his turning wasn't any smoother so I think it's a waste of time. Most sanding in our shop is done on large disc or belt sanders but when hand sanding is needed its a block wrapped with paper or just paper folded into thirds. We build foundry patterns so most surfaces are left machine finish. Sanding is only to blend profiles or size parts.
Check us out at <austinpattern.com>
RichThe Professional Termite
I just checked out the website.
What a marvelous place to work!
New ideas comming in all the time and a great fab plant to get the projects started.
I am really impressed having done this work for myself over the last 40 years.
The best day I ever have is when I can take a concept from paper to product!
Thanks for the tour.
Bob Oswin
Bob
Yes it is a great place to work. Have a key to the door and can use the shop anytime. Currently have more chair parts piled on my bench than pattern parts. If you look at the last picture on the products page you will see a 20" jointer in the foreground with a 24" verticle belt sander behind it and the lathe next to that. The lathe will swing over 8 foot dia. and over 8 foot length. It is a gap bed design, the entire bed rides on tracks in the floor. The headstock has about 30" of travel to offset it behind the bed for large turnings or turning tapers and the headstock will pivot 7° either direction to turn draft on faceplate work. Many other features designed for pattern making. The next to last picture shows one of the 36" bandsaws. All this machinery as well as a combo drill press/mill/spindle sander, a table saw, the bench vises and much tooling is home-made by the owners Dad. We still make a lot of our own tooling. Is everybody drooling yet? <g>
RichThe Professional Termite
Cut it out Rich! Your making me cry!
One more question.
When your have an approved pattern, do you go to the next step such as roto molding, thermoforming etc or does that go to another shop?
I got to start hanging out at our local foundry!
Bob
Bob
We as a rule just build the patterns for castings or the molds for vacuum forming. Sometimes get into other wood or epoxy projects but don't do any casting or forming ourselves. What we build is mostly already approved design before we start building. Just a standard "old school" pattern shop, no CNC yet.
RichThe Professional Termite
I am still envious of you !
I'd just love the know what you have learned. You are really a lucky guy.
Imagine getting paid to go in there!
Bob
With respect to metal lathe tools used on a wood lathe:
I haven't done it, but I've got a friend who builds and repairs bagpipes. He uses primarily carbide tipped or other hardened steel cutting tools designed for metal lathe work to turn his blackwood for the pipes. He says it's the only thing he can use that will hold an edge for any length of time working with this hard, dense material.
With respect to you hollow vessels -
At the last meeting of the Seattle Woodturners, they had a demonstration by a guy who turned a Christmas tree ornament. He hollowed out a ball from maple using a small diameter boring bar with a crook in it and ... turning in reverse. Something I'd never seen before but have tried and it works great. Just make sure you have your face plate or chuck locked onto the spindle - I had a pretty nasty catch the second time I tried it and had a Oneway chuck with #3 jaws spin off the spindle. Needless to say, that was pretty exciting.
It seems to fly in the face of everything we see or read about turning but it works great. My headstock doesn't rotate and I don't have an outboard tool rest. So either I lean over the bed or sit on the lathe to hollow out a piece and espectially if the rim is undercut, it makes for a rather awkward position.
I go to extremes about this since, if you're fab'ing your own tools, you might think about making a boring bar with a crook hooked to the right rather than the left so it would work for reverse turing like this.
...........
Dennis in Bellevue WA
[email protected]
Dennis02,
Years ago I wired a reversing switch onto my old lathe and cut some thick leather as a washer between faceplate and shaft. The washer gives enough 'grab' to the faceplate and also eases removal. Therefore, I can turn both directions, which really is an asset when sanding. Of course when turning clockwise you have to be really careful. Even so it is inevitable that a tool will someday catch and the faceplate will come off. For that eventuality, I installed the switch very close to the headstock. If I was a better electrician I would have installed a "panic" switch; which now that I think about it I might hire someone to do. Still haven't tried the boring bar idea as other projects take priority. Kind of getting the 'itch' though if you know what I mean.
sawick
Most face plates these days are drilled & tapped for a set screw to lock them to the spindle. I just have to remember to put the setscrew in is all!
As for the tools for reverse turning - I don't have a 'backwards' boring bar or hollowing tool yet but I've tried gouges and they seem to work just as well. Kinda odd after working the 'normal' way then doing it in reverse. But it sure makes hollowing a lot easier. Of course it's kinda comfy sitting down on the lathe bed turning normally. (grin)
...........
Dennis in Bellevue WA
[email protected]
DENNIS 02
Was paging thru some old FWW magazines today and noticed that David Ellsworth has a technique of straddling the lathe so as to get an angle on the tool to do hollow forms. What I am after in my boring bar ideas is a 'better' way. That means safer, less gymnastic, and predictable as to results. When turning wood by hand there are more than enough issues to deal with. I sense that metal lathe techniques have a lot of that figured out. That is why I wonder why similar tooling has not been applied to woodwork? Please understand that I am not after a strictly mechanized form of bowl production here. Rather, I am just looking for a way to continue artistic expression sans the danger, carpal tunnel syndrome risks, and in continual pursuit of the quality.
You must tell me how you accomplish a shearing cut with a gouge by working backwards. The best I've managed so far is scraping when turning 'backwards'.
sawick
As for metal lathe work vs wood lathes - I don't know if the latter encompasses what I'll refer to as reverse curves. That is, say you're turning a bowl where the top curves in towards the center. As opposed to a vessel with straight sides.
That being the case, for the reverse part of the curve, you can ride the bevel with a gouge the same in reverse for the upper part of the vessel. Not sure if this is clear, but I've had some success with it getting a true shear cut. You have to have the inside of the piece pretty well opened up to start the reverse turning process.
Raffin, in his books on turning, emphasises proper weight distribution - feet under the shoulders, blah-blah-blah .... using the reverse turning approach, you're working in the same posture as you would be working on the outside of the piece or in ordinary spindle work.
If I get a chance tomorrow I'll try to figure out a setup to illustrate what I'm trying to describe. But don't forget - at least as far as I've seen - metal turning usually has the cutting tool mounted in a fixture and is transported by a tool holder on traveling carriages. The cuts are considerably lighter. The work piece is turning quite a bit slower.
I've had more than my share of serious catches so I'm not waving off our attempts at safer ways to work. ...........
Dennis in Bellevue WA
[email protected]
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