Chuck jaw truing tool

[C-Bag]

Thanks Frank. Good points, and ones that I've had to consider and check. I like what you mention had to go through these checks not because it was over used, but because some things were never assembled right. Some things were not adjusted right. Some things were not machined right. So it's taken all this time to learn how to fix, check and go through all the different problems. Now I'm to the point where truing the chuck is a possibility. I am deeply appreciative that there are so many that share their knowledge freely here.

[olderdan]

Olderdan can you tell me what would be an appropriate rotary tool bit for truing the jaws with? Abrasive, carbide burr? I'm finally to the point with things to make the ring and think my Foredom mounted in sturdy mount would be able to do the job as it's the heavy duty model. It can mount a 1/4" shank, so I'm trying to figure what bit I'd need to do the cutting with.

I also assume after the Chuck is trued, it should be disassembled and completely cleaned, no?

Hi C-Bag
I start with saying that I avoid using the lathe for grinding if poss, having said that it is sometimes the only option.
The main enemy is loose wheel grit which is unavoidable as grit wheels are designed to shed the blunt particles to keep working and then there is wheel dressing to cope with.
My preference is a diamond coated wheel known as Speed pins in the UK these do not create loose grit and do not need dressing.
They will also cut hardened tool steel and have a good shelf life if not pushed to hard and with a vacuum dust is minimal.
The 1/4 shank one pictured should ideally run at about 25,000 rpm, my spindle only reaches 7,000 but still seems to do the job, chuck speed about 50 rpm and slow traverse in and out until it stops cutting.
And yes cover everything (spray oiled newspaper) and as you say strip and clean afterwards.


Hope this helps.

[C-Bag]

Thanks Olderdan. Once again having the proper name got me to the appropriate place. All I could think of before was diamond grinding bits after trying several other terms. But they never had the larger head which is needed to clear the shank and the grinder like the one in your picture. Doing a search with diamond speed pins got me into a whole 'nuther and proper universe. The net can be a wonderful tool, but without the proper nomenclature it's useless.

[Toolmaker51]

On the subject of trueness of 3 jaw chucks I have used a method which is is a little unusual and may not meet with everyone’s approval. I have turned the backplate register -.008 thou to allow a small amount of movement for final adjustment if needed, after which the mounting bolts are tightened, I can almost here the disapproval but I can say I have never had the chuck move while in use, indeed all faceplate work is clamped so why not a chuck.

This was commonly done decades ago, before commercial chuck manufactures 'named' the work and patented it. Then other manufacturers renamed it and followed suit.
My largest 3 jaw, a genuine Buck, has them, so that chuck is the go to for repeatable work. Unbeatable with pie jaws, every bit accurate as collets. And collets with 15'' capacity are quite rare...Single drawback, shouldn't run past 1500 RPM. American Tool Works Pacemaker 16" x 54" tops out at 2000, one feature making it IMHO epitome of toolroom lathes. Been looking for time to produce collet chucks for #215's and 5C's. Also have Jacobs Rubber Flex, that I keep at work. You really can't have too many options, when it comes to workholding.
Interested parties might research the Jacobs as they are reasonable used, no longer appear to be made. They are simple, easy to maintain and repair. The Sjogren Speed Chuck is similar and perhaps somewhat superior. being tied to Hardinge makes it $$$.
One thing I've not seen commented on is chuck size and RPM. Many mini-lathe chucks are cast iron and balanced only to RPM range of the intended machine.
Better chucks are "semi-steel", with increased longevity, repeatability, and balance characteristics. But all chucks have maximum safe RPM's.

[NortonDommi]

Here's something from 'Popular Science'. There was a post recently by someone who suggested using a ring cut from pipe set on the outside of the jaws and the jaws wound out which I think would allow the backlash in the scroll to introduce inaccuracy. This works for me.

[Al8236]

Here's something from 'Popular Science'. There was a post recently by someone who suggested using a ring cut from pipe set on the outside of the jaws and the jaws wound out which I think would allow the backlash in the scroll to introduce inaccuracy. This works for me.

Funny that's the very article I used to make mine several years ago! Works a dream holding the tips of the jaws bell mouthed the way most wear is on older chucks!

[Toolmaker51]

Like I said; comparatively nothing new under the sun. Mechanics and physics, like mathematics have enduring qualities making them not just interesting or useful. They are the very foundations of civilization.

Chuck wear occurs in several areas, depending first on construction of chuck itself. How they are used magnifies all of them.
By far, the degree of wear is due to who owns the chuck.
Lax supervision, ineptitude or poorly instructed users are main perpetrators.
Over-tightening and short parts are the next culprits, followed directly by maintenance.

Hard to say how many generations back truing rings go. The 'Popular Science' page is very telling; re the brick-drill made of pipe. How long has it been since fedoras were associated with workmen? Lol. Certainly after machinists wore waistcoats and neckties. I personally recall articles in Popular Science that belonged in Popular Mechanics. Never figured out how they were 'science' per se. Nothing's changed, look how term 'technology' is overused by advertising cause it sounds impressive. Not factual, just impressive to those susceptible.

[basil3w]

OlderDan-

How is your dog doing now? (Have you gotten any sleep?)

[olderdan]

Hi Basil3w
Thanks for asking about our shiatsu, I am afraid we lost the poor little thing 6 months after the eye op due to kidney failure, we would not have put her through it had we known.
We now have a miniature poodle to keep our bishon (my avatar) company and now he has problems so a good nights sleep is a thing of the past, at least I no longer have to go to work at 6 in the morning so it doesn't matter that much.

[Paul Jones]

OlderDan,

Sorry to about you loosing you Shiatsu.

Yesterday I had to euthanize our 13 year old Miniature Schnauzer, Emme, due to kidney failure. She was number seven in a long line of nine schnauzers we owned over a 35 year period. Emme was one of my most favorite Miniature Schnauzers because when we were at the breeders in 2005 (born March 4 ) selecting from a litter to pick for a female puppy when she choose us by falling asleep on my shoe. My wife took a photo of the event and that sealed the deal.

Below is another photo. Emme is the one on the left with her older sister Morgan (our number 6). Both beautiful, loving and energetic dogs but no longer with us. I built the hallway gate for them ( http://www.homemadetools.net/forum/h...dog-gate-37959 ) but in her day, Emme could fly over this barrier with ease and I would just laugh seeing it.



We always have at least two Miniature Schnauzers to keep each other company and currently have an 11 and 8 month old females with lots of energy. We are considering having miniature poodles to provide us and the schnauzers company when I retire this summer. My wife and I love dogs.

Sincerely,
Paul R Jones