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Headstock alignment

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Olin

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#1
Greetings

I have a Grizzly G4003G 12 In by 36 In Lathe. To get it in my basement I took it apart including taking the headstock off the bed. I must have done a fairly good job of realignment when reassembling, at least on short cuts I don't notice taper. However, on internal boring I do seem to have a very slight taper. Now this might be tool flex of the boring bar, but it might be mis-alignment of the spindle with the ways. The headstock sits on flats and has a flat base without any locating pins etc. A very brief search of for my manual didn't turn it up, but as I recall the headstock has adjustment screws on on the left as you face the lathe but not on the right of the headstock.

My question is: What are the methods for checking headstock spindle alignment with the ways? I know how to check if the headstock and tailstock are in alignment, but the test bar method only tells you that your centers align with your ways. I do know about spindle bars, but at ~$250 US for an MT5, that's pretty steep for a gadget you might use once or twice. I have thought about a laser center finder, still a bit on the expensive side but with a wider range of uses. Then I thought; how do you know you have the laser reasonably aligned with the spindle bore.

I know I am only going to achieve a degree of alignment, as a hobbyist I know I'm likely not going to achieve the repeatability that the machine is capable of achieving. Nonetheless this potential misalignment has me scratching my head and I'd like an inexpensive way to check spindle alignment.

Thanks for any thoughts.

Olin
 

Richard King

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#2

Olin

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All

Well, I will update this thread with my most recent results: I turned a tube between centers, found that my tailstock and headstock weren't lined up either. I guess I won't belabor this thread with the trials and tribulations of getting my headstock and tailstock lined up, but it was a struggle and I quit when I got to 0.002 inches in 15 inches.

I changed from a three jaw to a four jaw, making as sure as possible that the nose, a DI-5, was clean and free of scarf. I checked the runout of the face of the four jaw; 0.002 inches, probably as good as it's going to get. I chucked up the tube I'd turned and since the directions given earlier said that the average runout method wasn't dependant on chuck accuracy I quit when I got the tube centered to 0.001 ~ 0.0015 inches. Note; I was careful to get the DI plunger level with the ways and at the center of the test tube. I then checked the far end. I have a little bit more than 13 inches sticking out and found 0.052 total runout. To check for a bent tube I found the high spot and ran the saddle to the headstock end; 0.025 inch bend in the tube. I then moved the saddle down to the far end of the test tube and found the low spot, this time running the saddle up toward the headstock found 0.027 inch bend the other way. So, I'm thinking that at most I'm 0.002 inches out of alignment in 13 inches, although if the headstock end high spot was opposite the the far end high spot, the misalignment might amount to 0.0035 inches

I'm wondering if this is about as good as it's going to get. More importantly, I am wondering if I can live with it; I have my Lathe up against a wall and to get at the adjustment screws means moving the lathe away from the wall, removing both the motor and motor mount, the quick change gearbox and most of the gearing on the back end of the lathe. Once moved, re-leveling the ways and then trying to improve the headstock alignment. (Then re assemble, move it all back and re-level again.)

I'm fully aware that accepting this degree of misalignment means I will never obtain the results that a more careful attention to such matters could result in, but well, it's a hobby, not a living. I'm not in as good health as I'd like. The idea of moving the lathe by myself, doesn't fill me with the excitement that getting it in place did years ago, and so on.

Perhaps I will do the two ring test also just to confirm the above result, but that would have to result in a more significant, well to me, error, to get me to put the effort into rectifying matters.

Note, I hope no one gets discouraged in their own striving to to do the best work they are capable of on account of this post. Ultimately it's up to you to decide what you are willing to accept or what's reasonable to expect.

I do want to say thanks to those who replied.

Olin
 

Richard King

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#5
Your making this way to complicated. Did you read post number 1 in this link? http://www.hobby-machinist.com/show...-Tailstock-with-Headstock?p=106737#post106737

The jaws are important if the chuck is bad, but when you are testing for the headstock alignment you are following the accuracy of the spindle bearings when you are cutting a part and not the chuck If you turn a piece of aluminum it turns easy. Then turn it down the spud and indicate it to the outside of the tails stock quill you will be right on No worries about the taper being burred. etc.

In my professional opinion the rollie dads test is not as accurate as the test 2 collar test used as we do it in the link. There is a 2 collar test used between centers but I am not talking about that one I am only talking about the test in the link If you are happy with .002" leave it If you want to get it within 0002" try the other method Good luck. Rich
 

jgedde

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#6
Don't try to use the tailstock at first. Then you're chasing two misalignments. Get the headstock set first, then align the tailstock.

I have the same lathe and it isn't difficult to align - just tedious. I like to use a thick aluminum bar (somehting like 3" in diameter) for alignment. In other words, somehting thick enough not to deflect.

John
 

Ray C

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#7
Your lathe should be capable of much better than 2 thou over 15". Hope you don't mind me saying this but, sometimes it helps to take a break or step back and review some of the info that Rich and others have sent your way. If it makes you feel any better, when I was aligning my lathe, I had a brain cramp for a while and spent a solid day chasing my tail. -Happens more than I care to admit but do realize the thrill of victory makes it worthwhile.

Ray
 

Olin

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#8
All

Thanks for all the advise, I don't usually work in the workshop of an evening, so it will be next Saturday soonest before I report back. I'll have to get some material first, don't have anything on hand ~ 3 inches in diameter by say 10 to 12 Inches long.

Actually since I'm a Plumber by trade, I've been thinking about getting about 3 foot of 1 inch nominal Iron pipe size plumbers pipe, about 1.3 Inch in Dia. I know that the steel used in that stuff is not very good especially since a great deal of it comes from offshore of the US. However since the G4003G has a spud built into the far end of the spindle, I should be able to get the pipe very closely aligned with the spindle. 0.0005 or maybe better if I'm patient. I'd check that for runout at the far end and see how far off it is.

I do know that plumbers pipe isn't all that round and not very straight either, but it's inexpensive and being tubular should be reasonably stiff. I could "map" the tubes diameter at the spider, at the headstock and at the far end. I'd have a reasonably good idea of how much inherent variation in roundness I'm dealing with and be able to allow for it.

If I'm within 0.0005 or better at the headstock and I know the inherent variation in roundness, the average run out that is left should equal whatever the tube lacks in being straight plus the misalignment.

If this shows say 0.002 inches in 24 inches misalignment, then I'd find a suitable piece of round stock or gasp! order a suitable piece of round stock and do the ring test. I did say I was cheep didn't I?

Rich, I did read the write up of aligning the tailstock using a spud. I didn't have a piece of round stock close to the right size on hand and well, I already had the piece of tubing chucked up. I may have already mentioned this: I started out trying to make a standard for a small hand tapper. When I found the tailstock end of the tubing I used was some 0.007 inch bigger than the headstock I knew I would have to realign the tailstock and headstock, as I'd already turned a center down, and was driving the tube with a dog, I thought that it would be easier to get that resolved. I didn't consider that getting the headstock aligned first was a requirement, and well, I didn't think that the headstock was that far out either at the time.

Well that's why I came here; to learn, and if nothing else some one else will discover what I've learned without having to go through the process.

Again, thanks to all.

Olin
 

epanzella

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#9
I have the G4003G as well. I bought a 12 inch piece of 1 inch drill rod. Rolling it on granite and shining a light under it has shown it to be dead straight. I have ordered a 5c closer and a 1 inch 5c collet which should arrive this coming week. Assuming the 5c setup accurately holds the drill rod, I plan on checking headstock alignment by indicating 6 or 8 inches of the drill rod with a DI in the QCTP. Facing and center drilling the drill rod with very little of it sticking out of the collet should give me a decent test bar for checking the tailstock after the headstock is deemed OK. I'm no big time machinist but this seems to me like it would work. I needed a 5c setup anyway.
 

Olin

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#10
epanzella,

At the time I bought my G4003G, Grizzly didn't make a collet closer for it. I ordered one for the same spindle size but for a lathe with a shorter spindle. I had to make some modifications to the closer, I didn't use the entire quick opening mechanism that it came with. I made some tubes and an adapter for the outboard end of the spindle and used one of the adjustment nuts as the basis for a hand wheel closer. Slower and somewhat more clumsy than a closer designed for the G. I've since used the method you describe with a rod out of a 4 foot wide Printer, That's the principal reason I think I must be very close, I had less than 0.001 average run out over 24 inches at the time.

All the best.

Olin
 

epanzella

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#11
epanzella,

At the time I bought my G4003G, Grizzly didn't make a collet closer for it. I ordered one for the same spindle size but for a lathe with a shorter spindle. I had to make some modifications to the closer, I didn't use the entire quick opening mechanism that it came with. I made some tubes and an adapter for the outboard end of the spindle and used one of the adjustment nuts as the basis for a hand wheel closer. Slower and somewhat more clumsy than a closer designed for the G. I've since used the method you describe with a rod out of a 4 foot wide Printer, That's the principal reason I think I must be very close, I had less than 0.001 average run out over 24 inches at the time.

All the best.

Olin
The Grizzly drawbar and the 5MT-5C collet adaptor came today. What a dunce I am, I should have ordered the spanner nuts at the same time, they're under ten bucks. I figured I's just make them but forgot they were metric. I'm not gonna get involved with change gears and burning up time I don't have to save such short money. I'll order them first thing in the morning. I indicated my spindle with and without the collet adaptor today. The grads on the indicator are .0005 and it was moving about half of one graduation. Unfortunately the cheap 1 inch collet I bought won't pass my 1 inch drill rod so I'm probably gonna buy a Hardinge collet for the test bar for $32. I would really appreciate it if you could post a picture of your drawbar handwheel setup. Thanks,
Ed P
 

Olin

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#12
All

I don't know if I should blush or crow, some of both I expect. Well, I did "map" one of the ends of my 1 Inch IPS "test bar". I used a Chinese granite surface plate and a matched set of v blocks. Should have been a clue when the high spot and low spot were only about a quarter of the OD apart and varied 0.012 inch. Stuck the pipe, "test bar" is just too pretentious for this gadget, in the spindle bore. Second clue that this was a doomed idea; could not obtain better than 0.001 - 0.002 inches at either the Chuck or spider, and that was only because I decided that I would settle for the opposing jaws to agree.

After that, I got my runout at the far end of the pipe, noting runout in relation to the "mapped" out of round. I plotted these on a spreadsheet and found, drum roll please for the surprise!: I was more confused than ever, a huge investment of time to learn that lesson.

I looked the situation over and decided that if I turned a narrow area round at the end of the pipe I wouldn't have to worry about the out of round. So I chucked the pipe with about an inch sticking out of the chuck and centered that up as good as I could and took the lightest cut that cleaned up.

I reset everything, centering as good as the pipe would allow at the chuck and spider. 0.037 total run out. With visions of moving the lathe and tearing it down for adjustment dancing in my head, it came to me: take light cuts and see if the runout will clean up.

It was long and tedious and with 11 inches of tube that started at about 1.3 inches OD hanging out, perhaps a bit risky. I took 0.005 cuts and did succeed without a crash.

The best news: at the end, although the finish was rough, I ended up with a maximum variation in OD of 0.0005 and I truly think that's just a result of using such poor metal. My average variation in OD is more on the order of 0.0003.

I can't say that my headstock is in the best possible alignment with my ways, but I don't think I can be very far off and produce an 11 inch long turning, one that didn't have the outboard end supported, and produce an OD that consistent.

So, I guess I will go to the scrap yard and see if I can pick up something suitable, DOM tubing if I can find it, AL if I can find a chunk of that, and do the ring test, but I am fairly confident that better metal will not produce a significantly different result.

All the best.

Olin
 

Olin

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#13
epanzella,

Well I've attached some photos, guess we will see in just a bit if I can follow directions.

All the best

Olin

A note: you can't really see it in the pictures, I used one of the adjustments nuts provided and then cut a ring out of some flat stock, bored a hole to suit, drilled and tapped six holes right at the place where the adjustment nut and ring met. The six screws also hold the piece of sheet metal to which I epoxied the sixteen wooden segments that make up the hand wheel.

Olin


P6150007.JPG P6150008.JPG P6150009.JPG P6150010.JPG
 
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Olin

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#14
All

A further attempt to clarify my alignment issues based on a true ring test resulted in 0.004 IN difference in ring sizes. So its off to see what can be done.
I did find my manual. but the manual is for a G4002, I have the letter from Grizzly saying that is the case, apparently, I got my G4003G very soon after it entered Grizzly's line up.

All the best.

Olin
 

Richard King

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#15
What is s totally frustrating for me is I repair these types of issues all the time and trying to help via the internet is so difficult when I know it is an easy fix and can't help I wish I could just come and show you, but that's not possible. Last week I aligned a 24 x 84" Nardini Lathe that was cutting a .003" / 8" taper after the operator crashed the compound into the chuck. after about an hour of work of adjusting the head straight to the bed with it's adjusting screw under the head-stock, it is cutting .0001" / 8". I used the methods I described before, not these newly invented by hobbyist methods. Your head might be be out of alignment with the bed-ways too as we have seen that happen on here a few times. Too bad you can't find a local pro or a professional machinist to come over and help you. Rich
 

Olin

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#16
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As of this writing my head stock aligns with the ways. Using the ring test method, I was able to reduce the difference in ring diameter to 0.0001 Inches with the rings 10 inches apart, the out board end of the test shaft was unsupported. (DOM tubing, 1.625 IN diameter with 0.315 IN thick walls.) I unplugged my Lathe and took the rear gear train and quick change gear box off to get at the adjustment screws and the screws that hold down the head stock. I had forgotten in the six or so years that I've had this lathe that the adjustment are all in the back. That is correct, a cast lug along the rear edge of the bottom of the head stock, nothing what so ever to use as anchor point along the front edge of the head stock for adjustment. The Manual I have makes no mention of this, guess you just have to learn it your self. Taking the quick change gear box off was just a waste of time, especially since I had to put it back on almost immediately so as to take cuts.

I loosened three of the bolts that hold down the head stock and using a 0.0001 IN DI at the far end of the ring test piece I moved the the head stock just enough to give me a 0.002 IN movement at the end of the ring test piece. After tightening everything up and re installing the rear gear train and guards. I took some cuts and ended up with about 0.0004 IN difference in ring diameters. I was getting ready to loosen every thing up when it occurred to me to just put a little more pressure on the adjustment screw. I did so and got my 0.0001 IN result. After making sure everything was tight I said "good enough"

I then used part of the left over DOM tubing to make a spud after the manner suggested by Mr. King for head stock - tail stock alignment. Alas, I made it a little too small, tomorrow, I will turn it around and try that again.

Thanks to all who have endured this tale of learning.

All the Best

Olin
 

Richard King

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#17
Thanks, you made my night....I am glad I could have helped. Good night, Richard :thumbsup:

PS: Please call me Richard, Only the Doctors or Bill collectors call me Mr. King....lol
 

Olin

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#18
Richard

Your apparent level of experience and sophistication in metal working and your status as a Moderator, elicited the Mr. King title.

As things worked out, I haven't done any work in the shop since that post, the piece that I intend to use is sitting on the Head stock when I go back.

Thanks very much for your encouragement.

All the best.

Olin
 

Splat

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#19
FWIW, this thread should be in the Grizzly subforum.

Olin and all, I'm necroposting this in hopes it'll help others with their G4003G. A friend just got a G4003G and asked me for help in aligning it. I didn't have to adjust my headstock but on his it appears it might have to happen. We've ran my machinist level up and down the ways with the level sitting on the crosslide perpendicular to the ways. After shimming between lathe and stands the bubble doesn't even move traversing up and down the ways. He let it sit for almost two weeks and we just did the 2 collars test last night. On a 2"Dx12"L 6061 aluminum rod in a 3-jaw chuck he's getting 0.00325" over 10" with the larger diameter at the tailstock end. I'm wondering if this it too much stick out though. I just called my buddy and advised to take the bar down to 7" and do the 2 collars test again. I just received a roughly 12" sched 40 pipe that I'm going to take over to his house and try the test with. Maybe the 2" 6061 rod is too heavy for that much stickout. Any help or thoughts on this whole shebang would be appreciated.

Olin, did you have to really loosen the 2 bolts on the outboard and inboard side right under the spindle or just crack them? Also, did you have to mess with the 4 bolts on the rear of the headstock (above the motor)? Thank you.
 
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