Chuck jaw truing tool

[milomilo]

Thanks Chris
I would have installed set screws as you have done but the register on my old chuck is only 1/8 deep.
I used to operate a Myford cyl grinder with a griptrue chuck which had three tapered screws to bear on the register, I always wished it had four so it could be adjusted as you would a 4 jaw chuck.

I used only three set screws, as I find it easier to set the chuck, instead of four screws. Probably some sort of mental thing with me.

[C-Bag]

Hi olderdan, I've been working my way to being able to true up the chucks on my lathe. I'm having a hard time sourcing a 1/2"x5" test bar to set my headstock parallel to the ways. Can you post a link to where you would get one?

After that hurdle is over I'm going to make some truing rings like you show and true the chucks, but first thing first.

[Toolmaker51]

Hi olderdan, I've been working my way to being able to true up the chucks on my lathe. I'm having a hard time sourcing a 1/2"x5" test bar to set my headstock parallel to the ways. Can you post a link to where you would get one?

After that hurdle is over I'm going to make some truing rings like you show and true the chucks, but first thing first.

Reamer blank!!!!!! They're long, even center drilled already, hardened HSS, pretty damn straight and round. Couldn't really ask for better.

Example of item not price 1/2 Inch Diameter x 6 Inch Overall Length, 71110324 - MSC. Make sure they're center drilled, photo and description don't state. Diameters will = +.0002 -.0000 normally, straightness not much concern as they are ground after heat-treat.

[C-Bag]

Reamer blank!!!!!!

We have a WINNER! Thanks TM51. Can't search for what I don't know what the thing is called, so good call. Ordered! Step one in progress.

[olderdan]

Hi C-bag
Sorry I did not reply to your question, My dog has had to have an eye removed and I have not slept for 72 hours, next doors car alarm has been sounding off all day, the dog running all over the place trying to get its collar off has tripped me up and I now have a black eye in sympathy, you couldn’t make it up.
Feels like I am in the cast of that John Cleese film Clockwise.
In belated answer to your question I assume your lathe has an adjustable headstock alignment, if so I would start the process with a Morse taper test bar to fit your mandrel, or run a DTI across a faceplate to set it square,(I have always understood that lathes are set to turn faces very sightly concave but your choice).
Sounds like TM51 has got you sorted though.
Good luck
Olderdan

[C-Bag]

Olderdan I'm so sorry about your dog! That's horrible. I hope it it all gets sorted. I have this huge soft spot for dogs and there is nothing that gets to me like one of my 4 legged buddies getting sick or injured. My heart goes out to you and your dog.

Thanks for the tip on the collet, another purchase but worthwhile. If I'm going to actually try and do this right it makes sense, but being a noob it's good thing I have somebody like you to set me straight.

Get some rest.

[C-Bag]

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?

[Toolmaker51]

I'm ringing in, but not to usurp Olderdan, just two-centzin'.
Cover ways with plastic wrap 'glued on with grease or oil, draped wide to protect lead screw.
a] By ring, do you mean that which tightens on the outside of the jaws? They need to be 'secured' as if they are clamped on stock. Otherwise they float; sometimes the scroll will catch inertia and they exit the chuck. Not good, or worse....
To me, the choice would be abrasive. A burr's hard put to deliver a fine finish. Clamp the dresser somewhere to get whatever roundness the tool can produce. A proper feed rate and RPM will be apparent. In this case feed is more of an influence than speed. Misting some sort of mild detergent might work to keep wheel from loading. Visually the tooling marks shouldn't be pronounced. There must be some 'ideal' minimum chucking diameter per chuck size to achieve, guiding choice of wheel diameter, minus .050 or so, and narrow. Rotation is opposite that of grinder [as in conventional milling]. Surprise will be cuts deeper than a thou or two per pass.
The wheel shaft is sure to deflect contacting two jaws semi-simultaneously. Dykem or ink the jaws to monitor progress. Cleaning afterward won't hurt a thing; but I'd clean the scroll before hand so fines aren't inducing jaw position.
Disassembly easiest in most chucks by reversing the capscrews for 'handles' on the backplate. Set the chuck upright on bar or tubing that fit chuck body bore but not pas through the inner [adjacent to spindle]. Tap downward with hardwood in the jaw channels. Decently grease the various spuds and holes and scroll; I like a flux brush applying a thin coat. My/ our chucks all are on water-base coolant lathes, so I use boat trailer lubes.

This might be a nickel's worth, and bet a few bucks more coming in from our esteemed forum.
What more could a guy want? Have fun?

C-Bag drew my attention to Olderdans "Truing Ring". That post escaped me until now. Quite an improvement compared to commercial versions, especially for chuck sizes most of our forum likely use.
http://www.homemadetools.net/forum/c...ing-tool-50544

Which points out more details.
1. Test which pinion produces accurate chucking.
2. Typically those are stamped with something like ||| or |0|. Most chucks identify that as #1.
3. Consider modifying your chuck for an adjustable back. While yours is apart the opportunity is perfect.
The debate on using all three or one individual is ongoing. Lots of adjustable chucks have but one pinion. Drill chucks seem to tighten best with all three positions used...When it matters, I use all three and the |0| last.
And a nod to Frank S. All this is pointless if the spindle bearing is culprit.

[Frank S]

TM51 pretty much nailed the additional input log.
I just have 1 or 2 additional points which may not be germane to your particular lathe. I Just feel that it is important for someone to consider when attempting or wanting to true the jaws of their chuck/s By the time the top jaws become worn or out of true most lathes have already had a pretty hard life especially if they have been to use a truck driving term slip seated with multiple operators.
Like Tm51 stated cleaning the scroll is very important. I like to completely disassemble my chucks and wash them in diesel with a stiff brush. and re lube as he stated. But my point here is not the chuck at all but the spindle and its bearings. almost all older lathes I have encountered have had play in the spindle bearings.
old Babbitt bearings wear a lot and require attention form time to time by removing a few shims at a time. Newer bronze bearings usually are made like collets and will have a large adjusting nut to tighten them. the same goes for spindles with tapered roller bearings. Ball bearing mounted spindles are normally made with thrust bearings plus radial ball bearings Better lathes with ball bearings and thrust bearings will use angular contact bearings as well again there usually is a nut to set the pre-load.
SO I guess my point is check the spindle for run out before moving on the truing the chuck. because even if the chuck has been trued it is was done on a lathe with a loose spindle the best any turned part can be expected to turn out will be +/- the run out of the spindle

[C-Bag]

Thanks TM51, great tips like cleaning the chuck before grinding. And the protection of the ways. The ring is the ring that was the original post by Olderdan, which tensions from inside, not outside.