Eliminating chuck marks Q

[Walter Ambrosch]

I have been at turning for many years, just getting used to some newer bowl mounting methods.

How do you all eliminate those annoying chuck marks on either ti interior expanding dovetail or the calmping onto a dovetail tenon.

See the dimples on this mini bowl I turned today?

I use the Vicmarc 4 Jaw chuck.

THX, W

 

[robo hippy]

The tenon or recess needs to match diameters almost exactly with the diameters of the chuck jaws. A tenon will tend to show marks more than a recess due to the corners on the jaws. If it is wet wood, and you are getting black metal marks, some concentrated lemon juice will do it. If you juice it right after it comes off the lathe, it takes seconds. If you let the wood dry first, it takes a few minutes.

robo hippy

 

[dbonertz]

Turn the bowl around and use a jamb chuck or vacuum chuck to hold it with the tail stock (tail stock not necessary with vacuum). Turn the offending dimples off.

 

[Charlie Knighton]

i use the oneway stronghold chuck, and my jaws are the profiled jaws which make marks on the tendon or recess. i normally turn a tendon, reverse jam chuck and turn the tendon away. you can buy smooth jaws with the oneway chuck, but if you compress wood you will get a mark, i have not tried the lemon oil trick, but i have all profiled jaws.

 

[Walter Ambrosch]

The whole idea of using these fancy chucks is to make finishing a bowl faster with less steps. I try and get the recess or the Tenon as clost to the smallest dia of the chuck itself, but... you need to allow some wiggle room.

Just wondering if there are less problems with certain jaws over others or if Straight are better than dovetail?

I've been turning for 43 years and started way back when these chucks were just carry over from the metal industry.

So I know about all the tricks of jam chucking of other methods to turn the foot of a bowl.

I just find it so much faster to turn the foot to completion. Sand and finish. Then turn around a hollow out the bowl.

Once sanded and finished... you are DONE!

 

[hockenbery]

It is a third step
But my foot or bowl base do not have to be chuck size.

I use a tenon. When the rough bowl is dry

Jamb chuck it on the chuck with jaws open where it does not rock
Turn the outside and true the tenon
Put it in the chuck
Turn the rim and finish hollow the bowl.
Sand
Jamb chuck and turn off the tenon.

With this process I can turn a round bottom footless bowl
Or a foot the size of a quarter or one the size of a saucer.

Al

 

[Bill Boehme]

i use the oneway stronghold chuck, and my jaws are the profiled jaws which make marks on the tendon or recess. i normally turn a tendon, reverse jam chuck and turn the tendon away. you can buy smooth jaws with the oneway chuck, but if you compress wood you will get a mark, i have not tried the lemon oil trick, but i have all profiled jaws.

Charlie, I was going to say the same thing. The profiled jaws are much more gentle on tenons because of their smooth curved shape -- no advantage on recesses unfortunately. Some folks seem to mistakenly think that they have sharp serrations -- thee is an older design that does, but the ridges on the profiled jaws do not have sharp edges. For dovetail jaws, there is one diameter that results in a perfect circle. You can go to thew Vicmarc site and find that information in a table.

 

[john lucas]

It just takes me a minute or two to turn the bowl around and reshape the foot to anything I think looks best for the bowl. That way I an make the tenon or recess whatever size is appropriate for safety and reshape it later. It is a third step but I think it carries your bowls to the next level and well worth the time.

 

[Mark Mandell]

I just find it so much faster to turn the foot to completion. Sand and finish. Then turn around a hollow out the bowl.

Once sanded and finished... you are DONE!

Except for those chuck marks, right?

 

[hockenbery]

Except for those chuck marks, right?

Reminds me of some of the early bowls finished on faceplates
Cover the bottom with felt to "save the table top"
And hide the screw holes.

Al

 

[Gretch Flo]

eliminate chucking marks

I have been at turning for many years, just getting used to some newer bowl mounting methods.

How do you all eliminate those annoying chuck marks on either ti interior expanding dovetail or the calmping onto a dovetail tenon.




THX, W

Walter-I use a q tip and place water on the marks. Works maybe half the time. Sometimes I let the first half of the bowl set overnight so the wood at the base is dryer and marks less when applying the chuck for the interior. If there are black marks , I use lemon juice and q tip. Gretch

 

[Edward Weber]

It just takes me a minute or two to turn the bowl around and reshape the foot to anything I think looks best for the bowl. That way I an make the tenon or recess whatever size is appropriate for safety and reshape it later. It is a third step but I think it carries your bowls to the next level and well worth the time.

That's they way I do it as well

 

[robo hippy]

The only time I turn off the mount is for an 'art' piece like boxes or hollow forms. The method of mounting is a thing that turners seem to pay attention to, but the people who buy my bowls do not. There are no mysteries to it. If I turned my recess off, it is an extra production step, and I don't get paid for it. I finish turn the recess, then reverse. My chucks (dove tail Vicmark) don't leave any marks that I can see other than steel color, and that is where the lemon juice comes in. All of my bowls are warped as well, and the more they warp, the better I like them, and for some reason, the better they sell. Maybe if I had a vacuum chuck, but I haven't found a need for one yet.

robo hippy

 

[Syd Sellers]

I have been at turning for many years, just getting used to some newer bowl mounting methods.

How do you all eliminate those annoying chuck marks on either ti interior expanding dovetail or the calmping onto a dovetail tenon.

See the dimples on this mini bowl I turned today?

I use the Vicmarc 4 Jaw chuck.

THX, W

Walter, I have had pretty good luck eliminating these marks by putting a wrap or two of green painters tape around the foot before I put it in the chuck. The tape gets the mark instead of the foot.

 

[Gretch Flo]

not turning off the chuck method

The only time I turn off the mount is for an 'art' piece like boxes or hollow forms. The method of mounting is a thing that turners seem to pay attention to, but the people who buy my bowls do not. There are no mysteries to it. If I turned my recess off, it is an extra production step, and I don't get paid for it. I finish turn the recess, then reverse. My chucks (dove tail Vicmark) don't leave any marks that I can see other than steel color, and that is where the lemon juice comes in. All of my bowls are warped as well, and the more they warp, the better I like them, and for some reason, the better they sell. Maybe if I had a vacuum chuck, but I haven't found a need for one yet.

robo hippy

Reid-I am with you on this. I learned 12-14 years ago through books. (Raffan esp, and Judy Dittmer) Judy made little circles and things to decorate the base. I started doing that way. I do that on most and finish sanding before reversing. At craft shows, I have had 2 people tell me they love the way I finish the bottom. Yes, other turners know what I did, but the average customer doesn't. I do alot of natural edged bowls which makes my Oneway jumbo jaws unusable. Getting the rubber feet to fit is a PITA. If you don't make potato chip thinness and have the bowl leave the table when the door opens, or make the bottom so small that it rocks when someone puts their hand in the food container, then no one is going to see the bottom in a home situation (unless they are nosy!!!!!) Gallery quality stuff is different, I agree,. My 1 cent, Gretch

 

[Owen Lowe]

Walter-I use a q tip and place water on the marks. Works maybe half the time. Sometimes I let the first half of the bowl set overnight so the wood at the base is dryer and marks less when applying the chuck for the interior. If there are black marks , I use lemon juice and q tip. Gretch

To increase the effectiveness of dent removal, place a drop of water on the dent and then touch the water with a hot soldering iron or pyrography tip. The heated water/steam will penetrate the wood better and raise the dent. Continue heating drops of water until the dent doesn’t seem to be responding any longer. A touch up sanding needs to be performed after you ensure the dent-raising water has evaporated from within the wood, then finish as usual. Even if the dent is not raised entirely, it is usually much easier to eliminate whatever remains of the mark with light sanding.

 

[mokol]

i use Rubber Chucky Products,
they work well

 

[Steve Worcester]

I use a tenon (compression) and turn it off after I reverse it. Plan the bowls shape without the tenon.

 

[Bill Boehme]

The whole idea of using these fancy chucks is to make finishing a bowl faster with less steps. I try and get the recess or the Tenon as clost to the smallest dia of the chuck itself, but... you need to allow some wiggle room.

The perfect circle diameter is not the minimum diameter. As I suggested above, you can find the information you need on the Vicmarc website. Even at the optimum diameter it is still possible to crush wood, especially if you are using a very short tenon and applying excessive force when tightening the chuck. The subject of what pressure is "right" is fodder for a good debate, but I am of the opinion that crushing the wood means that the tightening force is in excess of what is necessary. Sometimes you may get a piece of wood that does not have a "right" clamping force because of spalting or whatnot (you gotta watch out for "whatnot" -- it is especially bad).

 

[Dale Gillaspy]

It seems to me it is quicker to reverse chuck it and turn the foot rather than spend time dripping water on a dent, then heating it, doing it several times, then finish sanding it.

 

[Owen Lowe]

It seems to me it is quicker to reverse chuck it and turn the foot rather than spend time dripping water on a dent, then heating it, doing it several times, then finish sanding it.

Absolutely. One word: Vacuum Chucking.

 

[Rob Wallace]

Absolutely. One word: Vacuum Chucking.

I am with Owen here.....

....my motto continues to be "Once you go VAC, you never go back"....

Like Steve, I plan and turn the bowl or vessel without including the tenon in the form, and then simply remove it when finishing the bottom. The vacuum chuck allows this to take place in minutes without the hassle of jam chucking or making special fittings or tailstock-held pressure devices. Rarely can I not use my vacuum chucking system; in those cases that I can't use the vac-chuck, I do jam-chucking with threaded adapters I made for my Oneway live-center; I have several different sized adapters that screw onto the 3/4"-10 tpi threading of the live center, and am able to take care of the tenon-removal/bottom finishing process fairly quickly. I drive the reversed piece with turned wooden fittings (made to be held in a chuck) that have different diameters, and the mating surfaces lined with leather or closed-cell rubber to provide non-damaging friction on the inside of the bowl or against the top of the hollow form.

Occasionally there are times that dictate using the tenon as part of the foot, but even in those cases, all of the dents or other marks are turned away in the final steps.

Turn safely!

Rob

 

[john lucas]

Well I do agree about vacuum chucking. What a great thing. But the other side of me goes with the keep it simple. I start most bowls between centers with the foot toward the tailstock. I keep the mark from the livecenter leaving a small tenon in the center of the foot. After I finish the inside and outside of the bowl I simply put a rubber jar lid opener over the chuck and bring the tailstock up and do what ever I need with the foot. It's quick, easy, and doesn't require any new devices. It takes me just a minute or so to cut off the small tenon left and then carve the rest away. Then I can sand it using my drill chuck and sanding disc.

 

[Steve Worcester]

The whole idea of using these fancy chucks is to make finishing a bowl faster with less steps. I try and get the recess or the Tenon as clost to the smallest dia of the chuck itself, but... you need to allow some wiggle room.
......

The other problem with smaller tenons, especially with open grain wood like Ash, is with too much force, you can shear off the tenon. The chuck can hold that well.