I have a question about the HF 7 x 10 3 jaw chuck.

[Metal_slicer]

What he is saying is we can't help you any farther untill you try to do something, like swaping out the jaws to find the combination that has the least runout or something like that. That way you have rulled out improperly placed jaws. It can be kinda, what's the right word, annoying but to a much lesser degree to try to help someone when you don't try to do something. Not saying you can't inquire more info but all that can be said has already been said and now needs to be set in action.

I hope you don't take it the wrong way, just trying to help.:hDe:

Cheers,
John.

I fully understand. It's really not a problem. I have done some of the suggested checks and perhaps I should have been more proactive posting the results. I have been on several forums in the past and It's very easy to have things taken the wrong way without any body language to go with the words. I sensed frustration which is why I replied the way I did. Perhaps I was wrong in doing so, I should have let it go. I can understand the perspective of people with experience feeling like they are ignored but I can only try suggested things if I have the tools to do so, and also when I have free time. With a wife, kids, work, 2 horses, 4 dogs, 5 chickens, and two cats and 5 acres, there always seems to be work waiting for me. ;D I appreciate all advice but not when someone is going to get frustrated with me. No one has to share their advice, only if they want to. For everyone who has provided me information I am fully grateful and look forward to learning as much as I can from you all.

Mike

 

[bazmak]

Hi the jaws have to be fitted in the correct sequence 1,2,3
yours are or the wobble would be far greater.So there are are 3 combination
of 1,2,3.Mark the chuck 1,2,3 with a felt tip pen.Start at 1 and fit 3 jaws
do the same with 2 and 3 and check each time for the amount of wobble
by eye if its the only way,or buy/borrow a dial indicator.Pick the best position and mark the chuck 1,2,3 with a centre pop.If the best position is not good enough,the swap the chuck. Regards Bazmak

 

[goldstar31]

I hope that John Rus will forgive me but the words of John Ruskin come more focussed.

He said 'There is hardly anything in the world that some man cannot make a little worse and sell a little cheaper, and the people who consider price only are this man's lawful prey'

Someone must have agreed because there is a monument to the man!

 

[bazmak]

Prior to following any of the advice i assume you have cleaned
the jaw teeth and chuck spiral gear of all swarfe etc
Bazmak

 

[Metal_slicer]

Prior to following any of the advice i assume you have cleaned
the jaw teeth and chuck spiral gear of all swarfe etc
Bazmak

Yes they are good and clean. I removed each jaw and checked the number vs the number stamped on the slot that they go in, and it checked out OK. all three numbers matched. I'm thinking the chuck is just not ground as precise as it could have been. It was suggested to take a felt tip marker and check the run-out in three locations but I have not done this yet because I really don't want to marker up my lathe. I think I am going to wait to get a dial indicator to do these checks.

 

[John Rus]

You konw, it is quite likely that there is nothing wrong with the lathe. If that's the case do you think 3/5 thou runout is good enough for what you want to do? If not the 10x22 lathes for about a grand by various manufacturs are much better (about 1.5 to 2 thou), they come with four jaw chucks so you can minimize as much as possible the runout of the lathe. Plus they are much heavier built.

Something else to think about,
John.

 

[wackyvorlon]

The spindle nose itself should have runout below the threshold you can measure. A spindle with two thou of runout has a serious problem.

A 3-jaw chuck with two thou of runout, though, is doing pretty good as far as 3-jaw chucks are concerned.

 

[petertha]

It was suggested to take a felt tip marker and check the run-out in three locations but I have not done this yet because I really don't want to marker up my lathe. I think I am going to wait to get a dial indicator to do these checks.

My felt pen rec was really intended as a quick/cheap/crude spot check. A quick wipe of lighter fluid, brake cleaner, acetone (nail polish remover).. any of those houshold 'light ends' & the felt mark will be gone. But whatever you're comfortable with, its your machine.

A test indicator will reveal all & its a very useful thing to have for future machining efforts. You can spot it against an accurate round in the chuck to determine runout & procede from there.

I cant seem to find a decent schematic drawing of your chuck mounting, but possibly this is it? Anyway, when you eventually get an indicator & check things accurately, this is one of the area's I was talking about (green arrow): the male protrusion OD on the spindle side is supposed to (closely) match the corresponding relief on the chuck side & the bolts basically hold the 2 components together (as opposed to centering them).

1) if the arbor runs true but this machined OD portion has runout, the mated chuck will just translate this runout & yield eccentricity to the test piece

2) if the OD portion runs true but has dimensional difference to chuck relief, also bad. Example, say the OD stub = 2.000" & chuck ID relief is 2.010". If the bolt holes are sufficiently oversized to will allow the chuck to be canted off to one side where the circles meet at a tangent, the chuck will show 0.005" runout with perfectly centered jaws. This is another potential source of runout.

3) if some combination of 1) + 2) PLUS some jaw centering runout collect in the same direction, you could see even more cumulative runout on the test round. So you have to test & isolate systematically.

Hope this helps, be interested to see what you find out with your ne measuremt tool.


http://littlemachineshop.com/Info/Images/33684Parts.jpg

 

[petertha]

Hopefully this sketch makes sense. Diameters exaggerated to help visually.

 

[Tin Falcon]

try downloading this

http://littlemachineshop.com/Info/MiniLatheUsersGuide.pdf

tin

 

[Metal_slicer]

@ petertha - Yeah that schematic drawing is very close to what I have. Last night I unbolted the chuck from the spindle and did a visual check of the spindle, I can't see any run-out, in fact, I cant see any run-out with the chuck mounted either. When I look at the jaws however, It looks as though they are not closing on center. I went a bit further and installed the 3 external clamping jaws that came with the lathe to see if there was any improvement and there was not. It was worse actually. the jaws seemed to hang up when rotating the scroll as if there were burs. I think the chuck is just poorly made. I'm not going to worry to much about it, I will just have to use larger stock to account for this until I can buy a better quality chuck. Does little machine shop have good quality chucks that will work with this lathe?

 

[Tin Falcon]

Before you go crazy remove the chuck dissemble , clean and deburr. your problem could be something as simple as a bur or chip inbetween the mounting plate and the chuck or burrs on the scroll. Fit and finish is not a strong point on these lathes but something a little TLC can correct.

Consider these lathes a pre-assembled kit that you need to finish clean and adjust.
Tin