How to tune and level a lathe?

bruppert

bruppert

<Insert witty comment>
Silver Member
Can someone give me a step by step on how to tune this lathe? I have a fairly good idea on what I need to do but as I've never done it I am sure there are things I haven't thought of.

I have a Hightower Deluxe (6 months old). Something is out of line. It could be the tailstock, maybe the bed, I'm just not sure but I suspect at least the TS. I want to start from the beginning and get everything trued up. So before I try reboring the jaws or dorking with the tailstock again, I want to go step by step from the beginning.

I have all the normal machinist tools, layout dyes, indicators, machinist level, etc. I also have most common tools. I worked as a machinist for 14+ years and know most machineshop terms, practices, etc... I do not have a precision straight edge, although the 12" rule in my precision combo square might qualify. I have a 12" surface plate but nothing larger that I know is truly flat. I also have access to a full precision machineshop but I don't like to bother the man too much. He won't charge me and every time I go there we burn several hours playing and BSing... although the time doesn't matter to me, I know he has things to get done.

I'm considering attaching it to a machined steel or aluminum plate. Then on a CNC mill I can indicate and shim the bed true. The tailstock/chuck poses a different problem. I think Jacobs only gaur. those chucks to be within .005 So even if I get that accurately setup in a mill and dust with a woodruff cutter, would I be able to make it accurate? Probably be better off trying to lap it inline. But, I only want to do all this if I have to.

Just so there is no BS inferred in any of this. I am NOT unhappy with this lathe or with Chris. Chris has been very helpful, returns all my calls and I really like the versatility of the lathe. Something is just out of line, maybe the UPS gorillas dropped it, I really don't know yet but the tailstock is almost definitely out of line.

If you really know how to do this or have a good link, would you please share? Please try to remember I am doing this at home without any sophisticated equipment.

Thanks,
Bryan
 
3 quick issues I"m having

- Doesn't drill on center. I Center drill then when I use a regular drill I can see it jump when it starts to cut. I bored the jaws a month or 2 ago and thought I had the tailstock within .0015 Hmmm, guess I didn't

- Bore not true. I bored thru a 3.5" sleeve and the front is .004 smaller than the back. Boring bar held in a tool post, carriage used to feed. Couple .040 passes, then a couple light ones around .005 I have the gib as close as I can without binding, still a tiny bit of wiggle room. Yes, I am snugging the back screw as well. I did have less than an inch of the sleeve sticking out of the jaws. Maybe I need to try centering it in the jaws or use both jaws with a longer piece.

- If I get the gibs too close it binds in one or two spots.
 
bruppert said:
- Doesn't drill on center. I Center drill then when I use a regular drill I can see it jump when it starts to cut. I bored the jaws a month or 2 ago and thought I had the tailstock within .0015 Hmmm, guess I didn't

- Bore not true. I bored thru a 3.5" sleeve and the front is .004 smaller than the back. Boring bar held in a tool post, carriage used to feed. Couple .040 passes, then a couple light ones around .005 I have the gib as close as I can without binding, still a tiny bit of wiggle room. Yes, I am snugging the back screw as well. I did have less than an inch of the sleeve sticking out of the jaws. Maybe I need to try centering it in the jaws or use both jaws with a longer piece.

- If I get the gibs too close it binds in one or two spots.
Click to expand...

If you worked as a machinist I'm not sure why I'm offering help, (I'm no machinist) but I had a similar problem.

I bored my jaws according to the directions given here and I still cut cones, not dowels when I turned down short pieces of scrap.

I came to the conclusion that my headstock was not true to my bed/ways. I bought a 3ft x .75" dia. reference bar from SDP-SI.com (or was it SmallParts.com? I forget). The problem was that I bought it for roundness and when I checked with them on how straight it is, they said the spec was +/- .005" per foot - so not so good for straightness.

Anyway, using that bar I was able to shim my headstock a lot truer to the waybed (I think, given the .005 spec). But obviously (to me)as long as your headstock is not true to to your ways, and hence not true to your carriage, you will continue to bore/turn cones instead of true round parts.

My 2 cents,

Gary

P.S. I'll be really interested to hear what others have to say as it is still a problem for me.
 
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seems to be the nature of these small lathes. i've had a hightower for about 10yrs and have come to the conclusion that its better suited for small jobs. the carriage works better if you keep some transmission oil on it. the tail stock has issues because of the way its designed, could use a better bushing system. you can get some improvements from Chris. he has a 4 jaw chuck steady rest that cures alot of the annoying sleeve bushings working out of the bearing steady rest. for me, it made drilling more accurate because i can get the steady rest closer to the end of the work. spotting drills help but i've had good luck with starting small then working up to larger drills.
 
avscue said:
seems to be the nature of these small lathes. i've had a hightower for about 10yrs and have come to the conclusion that its better suited for small jobs. the carriage works better if you keep some transmission oil on it. the tail stock has issues because of the way its designed, could use a better bushing system. you can get some improvements from Chris. he has a 4 jaw chuck steady rest that cures alot of the annoying sleeve bushings working out of the bearing steady rest. for me, it made drilling more accurate because i can get the steady rest closer to the end of the work. spotting drills help but i've had good luck with starting small then working up to larger drills.
Click to expand...

WOW!!!!!!!!! That is quite the review.
 
Lexicologist71 said:
But the boring bar would be the same length, regardless of where you were cutting on the piece.
Click to expand...

Don't matter, the load will build on the tool the longer it is in the cut, not to mention chatter from the length to diameter ratio of the bar being less ridgid.
 
2nd, is to have the lathe bed level, for and aft,
Some minor twisting may be required to get it level.
A permanent place is best with a constant temp room is ideal.
Using a very sturdy bench, or remlam(laminated beam ) set in place as a base works very well.Having the beam supported by it's airy points,, about 5/9 (1/sqr3) =.57735 of the length serperaton between mounting points. so a 60 inch beam would have the supports 34.6 inches apart.
3rd,
If you have a finger type dti, set that in the lathe chuck, and the contact onto the taper of the tailstock. A small mirror is usefull here. Indicate the tailstock to the headstock.

4th, get someting, wood metal does not matter. hold it in the chuck, then centredrill the end. Space the tailstock out from the chuck about 6 inches or so with the piece located in the tailstock centre.
Take a cut to make a clean up of the diameter at the tailstock end, noting the dial setting. Take a cut to the same dial setting at the chuck end and about 1/2 way between. These cut areas only need to be about 1/2 inch long, enough to get a mic and measure the diameters.
Do this at increasing intervals along the bed with either longer pieces, or just using 1 long piece and feeding through the headstock more or less.
When the lathe bed is true, the difference between the tailstock cut and the headstock cut and middle should be the same.
If all 3 or 4 tests at different lengths are the same difference, you can move the tailstock 1/2 the error to make it zero.
If not, adjust the bed untill it becomes the same.
Also some drill chucks do not zero to the taper of the tailstock. For this reason, I recomend having a couple or so tailstocks.
When a cut is taken on a piece about 3 or 4 inches long, about 1inch diameter or so,no tailstock support, it should be straight. Very sharp tools are important here and the tool must be on CL.
If it is not straight, there can be alot of reasons, from twist in the bed to the headstock not being true.

5th, when it runs true, then you can set about truing the chuck jaws etc.
 
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Lathe tuning

I did a post here about two or three years ago on how to align the headstock
and tailstock on the hightower lathe. You might want to do a search and find that thread.
 
Gary, thanks. Oh, don't worry about me having been a machinist... I've forgotten more that I remember. I started out on a apprenticeship in the lathe dept doing put and take work, a year later I was setting up my own jobs and another year later I was the Lead/Setup-Man for the Milling dept. Although I did well, there are plenty of things I don't know about... setting up a lathe for instance :) All advice is appreciated!

I thought about shimming the headstock but the problem there is that I move it up and down the bed. I guess I could mark the spots and note the shim size and placement but I am hoping top avoid that. Did you ever find an accurate Ref. Bar? I was looking for one as well but ran into the issue you have, they were not accurate. I want ed something straight and concentric within a couple tenths over the entire length.


Avscue, I talked to Chris about his Steady Rest with the Chuck. Once I get this thing tuned as well as I can, I'll revisit that. Thanks!


Neil, nice writeup. Thanks for taking the time.

I am not sure what to do about #1. The bed on the lathe is aluminum with a hard anodize coating. I don't know how thick the coating is but I doubt its any more than a couple thousandths. So if I do too much I am sure I'd go through the coating. My buddy has a rig to do powder coatings but I am not sure about anodizing. Although I'm sure one of my friends has a lap table in their shop, I doubt I'll find one 4 foot long.

Here is what I've got so far:

The bench is a modified steel tech bench. I built the top out of doubled 2x4s with doubled supports every 16" held in with 6" lag bolts. I planed the high spots before attaching the 3/4" plywood top. Its fairly flat but not perfect. It is solid though.

- Removed everything I could from the bed (carriage does not remove easily)
- Cleaned the entire bed
- Stoned out all the dings on the bevel and top of bed
- Went over it with den. alcohol and 0000 steel wool
- Verified that it is not level. Odd part is that its not consistent. Some places are a littler more out than others. Sounds like its twisted
- When moving the carriage most places it runs free, in one or 2 sections its binds
- Took 1/2 a Valium


Bob, thanks. I'll look for that later and print it out for when I get to that part.


Now to get that table level then the lathe... I have a feeling this is going to take a while.

Thanks to All
 
level and tuning a lathe

I have a porper model b. Should I be concerned with these same leveling and tuning issues. I have checked level with a starrett machinists level and seems spot on. Tail stock and chuck run out less than .001 after numerous adjustments. with occassional cone shaped tips. Any advice
is always appreciated. cribbeecues
 
Took the other 1/2 of that Valium *sigh* (jk)

I got the bench fairly level... kinda hard leveling a bench not meant to be leveled.

The lathe bed is out in all directions. Looks like I'll have to determine the high spot and start shimming. I'm gonna sleep on that and try picking it back up tomorrow

Qmaker, much appreciated! There is a lot of good info in there. I'm wiped now but I go through that tomorrow after a good night's sleep.

Thanks to everyone for the help so far!
 
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