The Longworth Chuck...recommendations please.

Darren Wright

Administrator
Staff member
Messages
20,088
Location
Springfield, Missouri
So my neighbor has gotten into turning bowls, or is looking to turn bowls, and stopped by and saw I had the cnc going again. He was asking about if I might be able to cut out parts for a Longworth Chuck (http://www.woodworkersguide.com/2010/10/17/how-to-make-a-longworth-chuck/) for him. Not really knowing much about them I told him I'd look for a design that might work on my machine.

Well after doing a little research, it appears these chucks quite often let loose of the object they are holding as they are made to hold something symmetrical, which in many cases don't have something symmetrical chucked in them. It also appears they can cause injury when doing so.

So, what do I tell my neighbor, any better recommendation of a way to hold items in the same manor? Or can they be used and are there safer ways/designs of them (please keep in mind he is a lawyer, so I'd like not to get sued ;))?
 
(please keep in mind he is a lawyer, so I'd like not to get sued ;))?

Right there he disqualified himself to be your customer and anyone you would do a favor. Tell him, given the liability regarding these chucks, he has two options; build the thing himself or buy one from a manufacturer who already has the product liability insurance in place. That way he has the opportunity to see for himself how much cost is added to a product because of the propensity of lawsuits in this country.

I said it nicely. :rolleyes: :p
 
Mine came with the Penn State chuck I bought at the MLCS store in Philly last year. I have two sets of Longworth jaws, as I sold the chuck I'd had previously with my old lathe, and forgot to include the spigot jaws or Longworth jaws, and now I don't know how to get in touch with him to let him know I have them. The jaws are no good without the chuck, of course. The chuck with the extra jaws was not expensive, but has worked well for me. Penn State has it on sale for 84.95 at present. It is on their page under "Economy 3 and 4 jaw chucks."
 
Last edited:
Well, I appreciate the guidance there, but again, it's not doing the work I'm concerned about, more so for his safety and being able to recommend a better alternative. He is a friend and fellow woodworker, so what safe alternatives are there for him to do the same tasks as the Longworth chuck provides? I didn't know if there was a safer version of it, or different hardware that might make it safer, or if there is a different chuck style he should consider instead.
 
S

it appears these chucks quite often let loose of the object they are holding as they are made to hold something symmetrical, which in many cases don't have something symmetrical chucked in them. It also appears they can cause injury when doing so.

..I didn't know if there was a safer version of it, or different hardware that might make it safer, or if there is a different chuck style he should consider instead.

Not really.

One of my best friends teaches woodturning and it happens that this week his class is being introduced to the Longworth chuck. His caveats are a really well balance piece. Use this chuck only for turning the bottom and use it with the tail stock against the work piece until the very end. Then hand carve off the tiny tenon left over. Also, very light cuts. If you need more information, I'd be happy to ask him to share his lecture notes.
 
I have seen those in the catalogs and online and honestly did not like the setup. Seems to me they can't hold a piece as secure as a regular set of Cole jaws would. Can't the stops slide loose or something? Sure looks like it. I personally would steer him away from that. Just my opinion. I use a smaller set of Cole Jaws and then a larger set. Both are on separate chucks so I don't have to go changing things around every time I turn around. But, everybody has their opinions, especially the species you are helping out.
 
I've done several dozen bowls with my longworth and this has been my finding thus far (folks who've done more may well have more input):
  • Slow speed ONLY. I may get up to near 600rpm, but that cautiously and mostly around 200-300. A variable speed lathe makes this a lot less terrifying (side note I always turn the speed to 0 AND shut the lathe off when moving chucks, mounting new blanks, etc.. as a matter of course and habit, imho its a good practice if you have the option).
  • Always use the tail stock. Predictably this is the first rule I violate :rolleyes: but its not a good idea to do any actual cuts without the tailstock, I only remove it for some final finish sanding and that carefully and with some caveats in mind.
  • Works poorly for straight sided vessels. You need some sort of a lip or bevel for the rubber bumpers to catch on. I've been doing more "inward facing" bowls so sometimes use it on the inside of the rim in expansion mode.
  • Works poorly for oddly shaped vessels. I'd just avoid it for natural edge, square, oval, triangular edged pieces altogether. Its not a good solution here.
  • Feel free to use extra restraints. Its common to use stretch wrap, bungy type rubber band things (watch those hangups!) to other chucking systems. They work here as well.

The main advantage is that its fast to shuffle bowls on and off of if you're doing a bunch of them and they're quickly adjustable to alternative bowl sizes.

Competitors include at least:
  • Cole Jaws. You say tomahto, I say tomato. There are some differences in holding power but I don't think its significant enough to be definitive on one vs the other and the holding mechanism is very similar (and I've tossed straight sided bowls using both - don't use these for straight sided bowls)
  • Jam chucks. More flexible for weird bowl shapes. Not substantially better than cole jaws/longworth for holding power though. Slower to build and use (although a lot of folks just use a rubber pad over thier main chuck which works pretty well and is uber fast so that's somewhat attractive. I haven't been brave enough to try that theory yet :D)
  • Various forms of compression chucks ala http://www.woodcentral.com/bparticles/bowl_bottom.shtml - these hold really really well if made properly. They are somewhat slow to use and more inflexible for odd sized bowls since you need different pieces of them for various sizes of bowls.
  • Vacuum chucks. These reportedly work really well as long as the piece isn't to porous and you have sufficient safety interlocks to avoid suddenly loosing vacuum. Its on the eventual "this would sure be cool" list (and I'd be able to do vacuum veneering wich would also be super cool - interest in which was recently revived by the Beamers fantastic guitar build thread).

I'm sure I'm missing some there - others please add to the list :D

That's my $0.02 for whatever its worth.
 
Mine came with the Penn State chuck I bought at the MLCS store in Philly last year. I have two sets of Longworth jaws, as I sold the chuck I'd had previously with my old lathe, and forgot to include the spigot jaws or Longworth jaws, and now I don't know how to get in touch with him to let him know I have them. The jaws are no good without the chuck, of course. The chuck with the extra jaws was not expensive, but has worked well for me. Penn State has it on sale for 84.95 at present. It is on their page under "Economy 3 and 4 jaw chucks."

You're confusing a Longworth chuck and Cole Jaws. You have Cole jaws. ;)

I've got nothing to compare to the hit Chuck took when his Longworth chuck let go of that bowl, but the hardest I've ever been whacked by my lathe was when I was using a Longworth chuck. I had pretty much finished the bowl, and decided to remount it on the lathe and make one more cleanup cut on the bottom. Just one cut...who needs a face mask? Well, apparently I sure did. As soon as the tool touched wood, the bowl went flying into my face. (I was a beginner and the start of my cuts didn't have a lot of fineness.) After that, I A: Always wear face protection, and B: Use the tailstock when using a Longworth chuck or Cole jaws. And actually, I don't use either anymore. I'm comfortable just using a friction or vacuum chuck.
 
Not being a fan of either, a Donut chuck offers the same access, but 100% better protection...IMHO. Don't rule out a vacuum chuck, but it has lots of limitations.
 
Not being a fan of either, a Donut chuck offers the same access, but 100% better protection...IMHO. Don't rule out a vacuum chuck, but it has lots of limitations.

I have a small donut chuck that I used a few years ago... haven't used it years, but my cole jaws will handle most of what I put in the donut.. I had it before the cole's .... I also have the cole jaw extensions that PSI sold, I like them, but always have to turn my headstock out 45 deg to use it as it's minimum diameter is more than will fit over my ways... I only have a 1442....

I like the vacuum chuck, but I only have my shop vac to work with and there are some bowls that it won't hold... I did a walnut the other day that's still a little green, about 11 inches diameter and I left the walls a little thicker... it's too heavy for my vacuum to hold. Maybe if I get a good run on the markets this year I can look into a venturi (I think that's the one that works with the compressor?)... my buddy across town has
one and he can hold some pretty hefty bowls... 'course he's got a much larger compressor than mine, but don't think that has any affect...he
brought it over and we tried it on my compressor and it held pretty well. I forget how much vacuum we pulled, but it was pretty significant on
my compressor.
 
Top