Dealing on some equipment

[Boostinjdm]

Well....I just couldn't leave it alone.

Last night I turned up a set up bar (that's what I'm going to call it) so I can measure each chuck when I swap 'em.  The bar is about 12" long with no measureable taper and hard as hell.  Must be some type of stainless cuz I have never seen any rust on it.  Anyways, I mounted my 6" chuck today.  Put in my set up bar and it indicated .012" off at the chuck and double that a little ways out.  No problem.  We'll try again.  Removed part, swung it around my head a few times, rechucked it.  Still .012" off and double that a little ways out.  I did this a few more times and came up with exactly the same result.
Move on to next check.
Removed chuck and rotated it one cam hole on the D1-4 mount.  Repeated first method swinging the set up bar around my head and all.  Same results several times through.
Removed chuck again and rotated it one cam hole and repeated first method again with the same results.
Moved on to check number three. Swapping jaws in slots.  I didn't expect anything here to happen and measurements proved it.
Check number four was to try tightening with each socket.  No noticeable difference here.

My conclusion is that this chuck must be about perfect (well as perfect as I can measure) and the mount is fxxked up.

So.....Removed the chuck and put the indicator on the spindle directly.  .003" off on the mounting face, .003" off on the taper that centers the chuck, .003" off on the mt5 taper inside.  I marked the high spot and it was the same all three times.

Conclusion.....fxxking spindle is bent.

I thought I was buying something ready to use, guess I was wrong.

Now, I'm thinking I don't give a shit about the MT5 on the inside.  If I go with a collet set up, it will mount off the D1-4 mount.  Will prolly be home made.
So I need to get the mounting face trued up and the taper that centers the chuck trued up and the right angle and dia. 
I believe a tool post grinder is the proper tool for this, but I don't have one.  Any reason I can't get good results with a really sharp brazed carbide or HSS bit?  We are only talking about .003" here and I don't see how I could make it worse removing that little bit in all the right spots.  More than enough material to do it the proper way if I fail.

[fabr]

In all reality you will be chucking up a shaft,turning it to size and cutting it to length most of the time so who cares if it repeats? There will be very few times you'll need to rechuck. But.............................if ya just gotta...........................go ahead,knock yourself out. 

[Boostinjdm]

In all reality you will be chucking up a shaft,turning it to size and cutting it to length

Yes, but there are many things on my personal to do list that will require boring or cutting a face on one side and then flipping the part over to do the other.  I'm sure it can be chucked up and indicated in a four jaw to compensate, but do I really wanna?

I guess I'm figuring that if I get this stuff taken care of now while it's new to me, then I won't be kicking myself every time I use it in the future.

Second option besides machining true is to turn up a MT5 taper on a big piece of shaft and then use leverage and a floor jack to straighten it.  I'm not a big fan of that because it would stress the bearings and the spindle.  It would however retain the ground faces that are already there.

[Boostinjdm]

Gonna take a break and think it over.  May also check what a new spindle cost (not looking forward to that).  Then attack it later.


EDIT.

Just looked it up.  $827 

I can do lots of fookin it up and brazing and re-fookin it up for that.

[fabr]

Yes, but there are many things on my personal to do list that will require boring or cutting a face on one side and then flipping the part over to do the other.  I'm sure it can be chucked up and indicated in a four jaw to compensate, but do I really wanna?

I guess I'm figuring that if I get this stuff taken care of now while it's new to me, then I won't be kicking myself every time I use it in the future.

Second option besides machining true is to turn up a MT5 taper on a big piece of shaft and then use leverage and a floor jack to straighten it.  I'm not a big fan of that because it would stress the bearings and the spindle.  It would however retain the ground faces that are already there.

No,huge PITA but doable................
I'm sorry but,,,,,,,,,,,,,,,,,,,,, OMG,you just made my day. I'm REALLY glad you qualified that with this;" I'm not a big fan of that because it would stress the bearings and the spindle." You were just kidding weren't you?

[Boostinjdm]

No, I wasn't kidding.

I'm also no dummy.  There are major consequences to going that route so I prolly will not try it.  One of them being that Jet wants $511 for that bearing.  Two, it could possibly break the casting where the bearing is and that would be a death blow.  Three, I couldn't trust the spindle any more and would think about it breaking, flying off, and killing me every time I turned it on.  Four, not likely, but it could damage/warp/twist the bed.

Current plan for fixing it is to face off the spindle first.  That will bring it into a parallel plane with the ways.  The short taper will still be out .003" but my 10" chuck is an "adjust-true" type and that .003" can be adjusted out.  I will just have to clock it the same every time I swap chucks.  That .003" will not affect the four jaw at all.  I just won't be able to use my 6" 3 jaw for anything requiring less than .006" (?) concentricity.

In reality, I will prolly only be using the 10" "adjust-true" 3 jaw and the 8" four jaw.  I don't know that using the 6" will ever be beneficial.  It could prolly be sold off.  It's a direct mount style, otherwise it could be modified to be an "adjust-true" type and work fine if clocked the same.  Other than me mounting it for a few days, I'm not sure it was ever used.

[fabr]

Good luck on that repeatability on rechuck. As Fast said,a collet is your best bet  for that.Even then if your surface finish profile is not very smooth(and fairly hard) you will still not get a perfect repeatable chucking. But have fun getting it done to your satisfaction. Nothing wrong with that. I commend your dedication to perfection.Just gonna be a lot of work for relatively small if any gain. IMH(umble)O.

[Boostinjdm]

As Fast said,a collet is your best bet  for that.

Not if the hole it goes into is crooked.....which is where I'm at.  If I at least correct the D1-4 portion, then I can make a collet holder that attaches there rather than in the center mt5 taper (which will still be off).  I guess I should mention that I haven't even located a store bought collet set up so I don't know if it uses the Mt5 taper or the D1-4.

Even then if your surface finish profile is not very smooth(and fairly hard) you will still not get a perfect repeatable chucking.

It doesn't have to be accurate out to 4 or 5 decimal places.  I would be happy with the 3 I can measure.  From my consistently off 6" chuck that I measured this afternoon, I think that is doable.  If I get the spindle corrected, that 6'' should be as close to perfect as I can measure.  Even if I only get some of it corrected, I'm still better off.

I've worked with a lot of sloppy equipment and I see the chance to do better with my own stuff.  So being my own boss....I'm gonna try.

[Boostinjdm]

I may take a stab at making this type.
http://s170.photobucket.com/albums/u265/donsmonarch10ee/?action=view&current=DSC00222.jpg#
Yeah....I won't be buying this because of cost and the crooked MT5 taper.
http://www.topspincnc.com/products/5C-Lever-Style-Collet-Closer--for-JET-GH%252d1340,1440W-MT%235.html

[Boostinjdm]

Here's a vid so you see what I see.  Somehow I lost the part where I measured to outside of the short taper, but it's off the same as the MT5.

[Boostinjdm]

Fixed....   Nice job Boost.  Well thanks Boost. (pats self on back)  What the hell, I'm talkin to myself anyway.



Is it perfect?  No, but I think it's close enough to work.

[Yummi]

Is it perfect?  No, but I think it's close enough to work.

Good for you sticking to it and getting to a solution.  Does that mean you wont have to up chuck now?

[Bennyhanna]

if you need good concentricity on rechucking the second op
then buy some soft jaws and bore them to the size you need.
if possible you should be chucking on somthing as you bore the
jaws and this should rid you of your runout.

[fabr]

Fast was right tho. The scrolls are the culprit. Boost, try checking your runout when chucking/rechucking different OD pieces now. Take a 1" OD,a 1.5" OD and a 4" OD and test all of those out and report back. Doesn't have to be any sizes in particular,just a range.   

[Boostinjdm]

Last night I re-cut my mounting plate for the 10" 3 jaw since my spindle is now straight. Got the chuck mounted to the plate and adjusted it true.  Now any run out is a result of the chuck.

I tried with some pieces ranging from 1/2" up to 2.5". Chuck 'em up, measure, re chuck, repeat.  Did it many times with both the 6" 3 jaw and the 10" 3 jaw. Looks like I can repeat less than .002" at the chuck and less than .005" 8" out with very little effort.  There was several times I got 0 (that I can measure) at the chuck and .002" or less at 8" out.  Looks like I'm in pretty good shape at the moment.  This was all checked without a live center for support.

I'd feel comfortable just chucking up a part and making my cuts with out even checking run out on most of the things I do for farm stuff.  Finished diameter is much more important than concentricity.  You know, making stub shafts to weld in the end of augers and such.