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Thread: Chuck Runout
07-10-2008, 07:25 PM #1
How much runnout would be considered acceptable on an inexpensive import 6" three jaw chuck with a D-4 backing plate?
07-10-2008, 07:35 PM #2
If I could get .003" out of it I would be happy.
07-12-2008, 06:49 PM #3
That is what I expected
Thanks Crossthread thats exactly what I expected.
I have a Polomco 14 x 40 lathe, and needed a small chuck to hold some little parts for a project so I purchased a new inexpensive chuck on Ebay and once I received it, I was disappointed to find out it has over .015 run out. When i contacted the seller and told him I could live with .002 or .003", but not .015, he said, "to expect the runout of .002-.003 with a chinese chuck and a used lathe is haveing a little too high of expectations."
I have several other larger chucks (8" and 10") with less than .002" run out on that same lathe.
Am I being unreasonable or out of line wanting to return the chuck?
07-12-2008, 06:58 PM #4
You're talking about the jaws, right?
07-12-2008, 07:06 PM #5
Yes, run out at the jaws!
07-12-2008, 07:38 PM #6
Chuk Jaw Run-out (TIR)
Those polish-made chucks are pretty good!
I purchased a 4-jaw self-centering chuck, 4" dia., and mounted it myself on a home-made backing plate for my 1 1/2"-8UNC spindle nose.
Run-out with various dowel pins is about .0007", ie. less than a thou!
When I bought my "new lathe" in 1990 it was 24 years old with a 6" 3-jaw self-centering pratt-burnerd chuck. After I mounted it on a new, home-made backing plate the run-out also was less than .001".
The newer chucks are much better than those of say 40 years ago or older.
07-12-2008, 07:50 PM #7
I just hate havin to fix stuff to fix stuff, send it back, complain to ebay. Scheessh , too lite for a boat anchor.
07-12-2008, 08:55 PM #8
07-12-2008, 08:59 PM #9
Runout in a Chinese chuck? Never!
OK, that is a 4 jaw, but still, you would think they could file them by eye better than that.
07-12-2008, 09:03 PM #10
I agree that .003 is as good as it is going to get.
07-20-2008, 02:55 PM #11
.003? Wow, chucks really have improved.
What runout could you then expect from a decent adjust-tru type chuck in, the 1/4" - 1" range if you trued it at 5/8"?
07-20-2008, 04:50 PM #12
A new chuck?
Less than a thousanth.
This is what my buck 6 jaw adjust-true does at work.
07-20-2008, 07:06 PM #13
A bog standard 3 jaw running 3 thousands out would be fine for me, i would,nt expect much better.
07-20-2008, 07:58 PM #14
Boy I really got lucky with a Grizzly 14x40 I purchased about 10 years ago. It has .001" runout on the 3 jaw that came with it.
My new Victor 16x60 came with a really crappy 3 jaw and I have since replaced it with a new Bison 3 jaw.
07-20-2008, 09:24 PM #15
i never expect a 3 jaw to run true, so i 4-jaw all my precision work........
07-20-2008, 09:39 PM #16
swarf, that picture is hilarious - why do they even bother? Buy a good chuck, life's to short to mess with crappy tools. That someone says .015" is acceptable for a chinese chuck is perhaps the greatest indictment I've heard of chinese made tools. what do you get with an indian one ---- 1/16"?? sheesh
07-20-2008, 10:09 PM #17
Here's the latest
On request of the seller, I took the chuck apart and put it back together again all to no avail. It still runs .015 out. The seller did not answer two emails from me so I filed a claim through Pay Pal and gave them some information on chucks, including a link to this post. (hopefully they will read it)
Pay Pal did get a response from him and he is offering me less than half of my money back, and I could keep the chuck. This chuck is a piece of crap and I have no use for it, even if it was free I would not want it, so I declined the offer. We will now see how Pay Pal handles the claim.
I honestly do not think I am out of line refusing to accept a chuck with .015 runnout, especially as it is advertised as a new chuck. (after all, what manufacture could stay in business selling chucks with that kind of runnout?)
Thanks to all of you who voiced you opinion,
07-20-2008, 10:33 PM #18
Keep us posted on your dealings with paypal.
07-21-2008, 05:58 PM #19
The problem I have found with Chinese made 6" 3 jaw chucks (I own 3 all by different manufacturers) is not so much with the chucks, but with the D1-4 mounts for the chucks. I discovered that the chucks were not mounting fully flush on the spindle. There was a varying gap between the chuck body and the spindle mount. I did not want to mess with the lathe spindle so I removed small incremental amounts from the D1-4 taper mount on the backplate. It doesn't take much. I use 320 or 400 grit silicon carbide paper. I mount the chuck so that the back of the chuck is facing toward the tailstock (you naturally have to have two chucks to do this) I leave the pins in the backplate and turn the chuck by hand. It takes me less than an hour to fix the mount. You have to take the chuck off periodically and mount it on the spindle to see how it is fitting. I had not checked my chucks in a while, but after I read this thread I checked the run out and all three have .0015" or less of TIR. I have also done the same thing on two other chucks owned by a friend. Two of these chucks had integrated D1-4 backplates and rest had separate backplates.
I have wondered if D1-6 mounts or those with more mounting pins would be as prone to this problem, but I have no way to test that.
07-22-2008, 07:56 AM #20
Mikee, I will stick with .003" being acceptable for a cheap import chuck. .015" is not acceptable. What kind of mount is it (pardon me if you already said it) ? Did it come with a threaded backplate or did you make your own. If you made your own then make sure you allow a little play in the through holes from the backing plate to the chuck. Any binding here can cause a lot of problems. Cut your backplate VERY carefully to just slide into the recess on the back of the chuck. If the jaws are not concentric with this recess then you are hosed if you don't have an adjustru. I have a cheap Phase 11 and a Bison and they both run about .002" or so depending on how wide open they are. The scroll is obviously not perfect. With stock up to 1" it is about .001" out. With stock over 2" it is about .002 or .003" out. Bottom line is that what you have is unacceptable. I never trust my three jaw anyway but if I have a piec of stock I can throw in there and make a skin cut to clean it up, I don't want the thing top be flopping all over the place making me take off more then needed to true it up.