Lathe alignment tips on home made cbc lathe

[drew1492]

Looking for tips on aligning my lathe I have built. I had it pretty damn close and then did a final adjustment and it moved way more than I wanted. I have it pretty close now, but looking for suggestions on dialing it in.

91004

[Jackass Glass]

i think we loosen it all up. and put a tube in both ends. then tighten it down. should be damn straight if the tube is good.

[dustyg]

i think we loosen it all up. and put a tube in both ends. then tighten it down. should be damn straight if the tube is good.

No idea if that works, but it seems like a machined round stock would do better than a tube.

[Kovacs Glass]

First things first: Make sure the surface you have your lathe on is perfectly level and flat.

Then adjust the lathe bed so that it is perfectly level/parallell to the table.

Best thing to use to true up your head/tailstock and jaws is machine tungsten rods that are true and straight. Then using a dial guage, see where the runout is with the dial guage and adjust your chucks/stocks accordingly.

[lsspam]

Kovacs has it right, use a dial indicator. Tungsten is expensive, limiting ease of access, and does not machine easily. I usually grab some 1 inch aluminum round stock about 12 inches long for aligning a glass lathe.

There are two different measurements to make. First you should check the the spindle bearing without any chucks. On a tight lathe, the spindle bearings should have 0.002 of runout or less. Secondly you should attach your chucks and chuck up a piece of solid material. With material chucked up the headstock, on a tight lathe, should have 0.004-0.006 of runout and the tail stock will be out a bit more because is slides up and down the bed ways, 0.008-0.015 is the normal range.

From personal experience if the head and tail stock are more than 0.015 out from each other than you will cause extra strain in your seals. There are ways to midigate this strain if your lathe is really loose but that is outside your original question and would eat up a lot of time to post about properly as it depends on the type of seal, your tolerances, and what equipment you have available to you.

To adjust a lathe with planetary chucks you need to loosen you gib screws and adjust the three arms so that a chucked rod will spin within the tolerances I posted above. For a bison chuck (metal lathe 3 jaw chuck) you usually can not easily adjust the jaws individually, the simple way to align them is by jig grinding them in place on your machine.

There should be enough information here to get you pointed in the right direction. If you need any more help post here and I'll get back to you.

[drew1492]

Thanks for the responses guys! Definitely enough to get me going in the right direction. I think I am going to put some feet on it to help level it out.

[snoopdog6502]

Some new chrome hydraulic cylinder rod has a tough chrome plating that's been center-less cylindrical ground and polished.
The tolerance is very fine with then, really damn strait, very round,very smooth, not like a glass tube at all.

Buy 2-3 feet for a test bar 1" or 1.250". when they saw it off they should have a nice cardboard tube around it so it stays nice even though the skin is tough as hell.

You did a great job you should be proud of yourself. Even new big high dollar machines need to be sweeped in and dialed in.

[drew1492]

Thanks snoop! I ended up ordering some 1/2" aluminium round bar to play around with. I might have to try the hydraulic if I need something more accurate. I only have a 22mm pass through so I am limited on sizes.

Hopefully I can make enough on this machine to trade up to a nicer machine!

[Fantasy]

The easiest way to put two metal rod into the both chuck.
After that lay on the ruler on this two rod. and you can see
it is touching them all way long or not.

[PhantomGlassCreation]

https://www.instagram.com/p/BXMSNc-F05V/?taken-by=vertigo_glass
https://www.instagram.com/p/BXMcCoalcxs/?taken-by=vertigo_glass

Check out the links... This is the tool you will need to be accurate.
I believe they are called..."micrometers"

[snoopdog6502]

since all you can do to align a head stock is to get the taper out of it.

Dial the test bar concentric and strait, loosen the main headstock and clamp it down when its dead nuts true to the lathe bed.

Then loosen the tails side, clamp the bar carefully and tighten down the tailstock.

You shoot for straitness and perpendicularity and concentricity.

The tools you need is a mag base and dial indicator. 1/100 of a mm or 1/1000th of an inch is fine. a test indicator would be overkill (0.0001) resolution.

You get everything strait and true to within 0.005" you are OK, get it within 0.002" or less you are good to go.

Most any error beyond that is the chucks themselves. Good chucks will grab concentric less then 0.0015" without to much fussing.

[drew1492]

The aluminum round stock is quite helpfull! Trying to figure out how fast I want the tailstock to move with the stepper motor.

https://youtu.be/5VZLr-Du7po

[snoopdog6502]

looks like you have it dialed in nice.

Wow.

[drew1492]

I have it pretty close... I have a long way to go, but it is fun to play around with for sure!91058