Monday, December 31, 2012

Continuation of the JET GHL 13X40

The below represents some of the final suggestions made to the writer concerning the misalignment of the headstock and the bed ways:

from Richard King to the author:

I am writing this so those who have the same issue down the line can check their machine if they do not have all the nice test bars.

When you mic the 2 collars and they are good and you can do the face test and it's good, your all set. But if they are off what is wrong? The bed has a twist or the head is out of alignment. If you have a precision level like a 199 Starrett that the bubble is .0005"/12 graduations. Or even a 99 with a .005" / 12". Set the level on top of the cross-slide or saddle so it is 90 deg to the bed ways, mark the place your sitting with a magic marker. If you can level the machine or slide a feeler gage under one end of the level so it reads level. Have the saddle cranked up next to the head-stock, (HS) remove the test bar we just cut, or if you didn't level / align the bed first, level it before you do the 2 collar test bar. Adjust the machine or level so the bubble rest on the center and on a line. If your using the .005" per foot get a magnifying glass and a super sharp pencil. Mark the level where the bubble rests.

Now crank the saddle back toward the tail-stock (TS) about an inch and then move it back to where it was sitting stop the cranking always moving the same direction. Re check the level. It might take a few tries. Then crank it down the bed as close to the end as you can, if you can slide off the tail-stock,. then crank it the direction you cranked it at the other end and let the bubble come to rest. Usually it takes 10 seconds. If it is off adjust the leveling feet. I read you said it is spot on with the leveling, but if it isn't level the bed or use a level to "align the bed" Leveling a machine on a Aircraft carrier is tough don't you think...so aligning the bed-way parallel to each other is the key. If your bolted to a bench you will have some issues with stability I bet, but do the best you can and shim between the bed and the bottom of the bed legs. If it sets on a cabinet, be sure to check all the bolts holding the cabinet to the bed are tight. I also like to see the bed sitting on leveling plates under the leveling bolts.
 I know you have these test bars and I looked for a dumbbell online and could not find anything online to even know what it looks like.



Now that you know the bed is straight / level / aligned...You take the test cuts on the OD of the Collar. What is you reading? If it's a under .002" (.001" per side from center axis line). I would twist bed out of alignment so the 2 collar test cut straight. If the collar is big on the right side or TS end the mount a dial indicator where your tool is on the center of bar, and put .010 pressure on the indictor, then tighten the front side TS end leveling screw so the indicator moves .002". I know what your thinking it would be 1/2 that, but it won't be. Take .002 and take another cut. It should be good or you can tweak it again.

When done tighten the lock nuts with 2 wrenches on the screws and take one more cut. If it is more then .002 then the head is probably out of alignment with the bed. I used to be a repair station for Jet years ago. For the most part the machines were not the best, but people got there monies worth. Usually someone can follow the directions when they buy a machine and all will be OK, but factories do screw up now and then too.

If you double checked to be sure the cabinet is tight to the bed and its leveling screws are snug. I see the on the Jet Web-Site the head cabinet has 4 leveling pads. On a small machine it's difficult to get them to twist the bed unless they are bolted to the floor. But if the machine was build correctly you only put an equal amount of weight on those 4 screws and leave them alone.
Now here is my effort and reponsee to Mr. King:


 Headstock measurement on right:


 











The tailstock side measurement is shown on the right. About 0.003" difference, which is what I have been telling JET for more than 2 years. The bar is a high carbon steel bar, very difficult to machine. It was not moved ffrom the headstock during the operations. I used an indexable carbide cutting tool. The space between the collars, specified by Mr. King, was reduced 0.050". A light cut (<0.001)was made on the HS collar using Warner Companies HS insert.  The cut on the right collar caused some chatter since it was (0.007 dia). I then made an additional 0.0005" cut on both collars w/o moving cross slide.


I suggest anyone interested see :

http://www.hobby-machinist.com/showthread.php/8924-Jet-13X40-Headstock-alignment-nightmare-with-Walter-Meier?p=87520#post87520

for further details.

Much has occurred since this post. The entire operation per the above procedure was completed and as inexperienced as I am, the final configuration took about 40 hours. This is posted on the Hobby-Machinist web site as shown above.
Two issues were found. At the suggestion of JET's tech, the 4 jaw chuck was replaced by a Rohm Industries independent 4 jaw chuck. This chuck was found to be seriously flawed after much consternation and time. Quite possibly the OEM chuck is probably adequate; however, the alignment process was completed with the Rohm chuck, so the entire process must be revisited. Rohm did, after much discussion, refund my investment, shipping but not the time. Subsequently, I purchased a top quality chuck (BISON) for the same amount. It has not bee installed and the bed realigned as of this date, April of 2013. Did JET fullfil their responsibility? No, in my opinion. Finally I just accepted the fact they were not. They did send reps to the site, but realignment remained incorrect. I do not think they knew how to complete the task. The bed was misaligned went it left the factory.

Saturday, December 1, 2012

Assembled Eliseo W52 & Search for Accuracy

I am 70 and so I reserve December for me and my bucket list; thus I am at my range (130 yds) and workshop close to Remlap, Alabama, my home. Each day I sit on the porch, drink my coffee and watch the Michigan imported deer wonder through and browse on the acorns from the 100 year old oaks. From this same chair I occassionally call coyotes, although rarely answered. I thank GOD each day he allows me this pleasure. This week is clear cool weather and the "system" is assembled. Some of the earlier posts expressed the opinion the assembled system would respond to the search for accuracy differently from the test frame designed and constructed earlier in the year. To recap, this frame was used to assist ammo selection so critical for a 22 RF. The final results analyzed using a computer program which analyzed scanned target(s) data to a high resolution and made statistical projections. Thw W52 seen in the photo has a standard OEM chamber, termed "the Winchester chamber".
    The Win 52 shown above is to be fitted with metallic sights in the final configeration, but for conventional testing a 10X scope has been fitted. This scope is about 25 yrs old and has turret knobs, expensive at the time and as I remember about $400. The rings are Burris and the ring base is custom made and not finished. Burris rings are the low profile; however, for this application medium are on order. The turner is my own design and the affect is not fully resolved. There will be a front sight "bloop" tube also to mount the front sight. Somehow it must be combined with the tuner (not yet designed). You can see the stuff that must be assembled (I need a UPS for the logistics) for shooting and is not lightly promulgated.

The Winchester 52 Tube Stock Presumption-Postulus
  Now a brief word on the tube configuration. Nothing is so strongly believed as that which is least understood. Now that was me. The entire premise for this project was that the tube configuration would modify the boundary conditions (add stiffness) to the wooden stock W52 assembly and result in enhanced accuracy. From my reading, the vibrations induced by the propellant occur during projectile travel and the harmonic vibrations occur afterwards, like a plicked guitar string. The guitar string is deformed and the released for its harmonics. Same with the 22 barrel. The initial forces are resisted by the innate strength of the system; whereas, the later motions ( think of living in LA) are aftershocks and depend upon mass and strength.

The trigger mechanism location severely complicates the fitment. Especially if the builder is limited in experience with the lathe and mill. Further, my failure to completely "model" the system cost many manhours due to unforseen conflicts. My final assessment is a U shaped configuration would reduce the effort considerably and yet allow my postulus that a "clamped" action would respond favorably. Prior posts show this section, Figure XX, http://winchester52.blogspot.com/2012/09/eliseo-winchester-52-testing.html . My assumption is based upon many years in private practice as an engineer-surveyor, whether the result is measureable is yet to be proven.


NOW THE TESTING FROM SANDBAGS

work-in-progress