I have a question about lathe alignment

[daveghil]

That's a great idea. I couldn't find any tests bars longer than 12 inches so making my own I could make it longer and therefore more sensitive to taper over a longer distance. Will need to find or make a dog. And good advice about using a dead center. One more question though...if I rechuck the tapered center in the 3 jaw in the future, could that reintroduce some runout at the headstock? I've ordered a back plate and independent 4 jaw chuck so I could use that going forward.

 

[woodchucker]

That's a great idea. I couldn't find any tests bars longer than 12 inches so making my own I could make it longer and therefore more sensitive to taper over a longer distance. Will need to find or make a dog. And good advice about using a dead center. One more question though...if I rechuck the tapered center in the 3 jaw in the future, could that reintroduce some runout at the headstock? I've ordered a back plate and independent 4 jaw chuck so I could use that going forward.

That's why you need to recut the 30 degree (60 included) angle again, to true it up.
you could use the 4 jaw, but just get used to truing up the home made dead center, when it gets too small you make another.
It's kind of a standard.. faster than changing chucks, and the dogs use the jaws of the chuck.

 

[daveghil]

That's why you need to recut the 30 degree (60 included) angle again, to true it up.

OK..I understand now...thanks

 

[whitmore]

I'm writing this from my sick bed. It seems I have a lot of time to think right now.
I have always had about .004" to .006" taper over a 6" long cut. I have leveled my lathe but ...
I am wondering if placing a 40" X 20" steel plate 1/2" or thicker on the bench top and then mounting the lathe on the plate if that would help solve the problem of constant changing of the leveling. The lathe could be aligned to the very stiff plate and remain constant. Am I way out in left field in this thinking?

Making the underpinnings flat is one solution, but simpler would be to change the four-leg support to three-leg; it can
tilt with subsidence of a foot, but that won't twist anything.
A half inch plate is a LOT of cost for really minor resistance to twisting. A full torsion-box is more work, but less material
cost.

 

[mac1911]

I have a smaller lather Smithy 12x20 aprox 500 lbs I have no other option for space than my 12x16 shed
The shed sits on blocks on gravel
The floor was over built. 2x10 with 3/4” PT then 3/4 TG
I have 12x12x1/4” steel plate under each foot of the factor steel bench. Luck enough the feet fall right on the joists.
I have done a lot to get the lathe running well but I feel like im at the point I need to check for twist in the ways.

 

[Shiseiji]

I have a smaller lather Smithy 12x20 aprox 500 lbs I have no other option for space than my 12x16 shed
The shed sits on blocks on gravel
The floor was over built. 2x10 with 3/4” PT then 3/4 TG
I have 12x12x1/4” steel plate under each foot of the factor steel bench. Luck enough the feet fall right on the joists.
I have done a lot to get the lathe running well but I feel like im at the point I need to check for twist in the ways.

Mac, just another "opinion." To me the beginning is a solid base and a way to level/remove any twist from the bed with minimum effort. Without these two, anything done later can and will be undone when they change.

Start with making what the machine sits on as solid as possible. 1st spread the load across as many joists as possible on a continuous "something" solid. It's always a balance between |Good|Quick|Cheap| and generally you can have any two. 2 layers of 1-1/2" press board is a 8' X 4' X 3" base. It won't over load the joists and will resist sag. I'd also consider putting solid cinder blocks under each joist and shim them into contact. This is the same idea as lathe installation guidance on a second floor as was pretty common.

Now you have eliminated what you can towards a solid base. You can retain the square plate, but the factory steel bench is, IMHO, fine.

"If" it has holes in the feet, I'd install leveling feet with long threaded shafts. This is so starting at the foot end, using all grade 8 hardware, you have a nut, a washer, the machine foot, a nut, and then at the end of the shaft, two nuts jammed together. The last nut should be flush or can be a grade 5 acorn nut. FWIT, this is how a Monarch 10EE 3,200 lb lathe is leveled. It is not bolted to the floor.

The nuts above the feet are left loose, the top jammed nut is used to rotate the shafts to level the machine. Then the nut above the foot is tightened.

If you don't have convenient holes in the feet, the idea is still the same, you will have to decide between something similar or shims between the machine and the stand.

Now you have a solid base, and have removed any twist from the bed without having to, hopefully, shim between the machine and the factory stand.

Only after this can you reliably use test bars etc. to learn the nuances of your machine and see what can be altered, and what you will learn to work around.

Just my $.02

 

[mac1911]

Mac, just another "opinion." To me the beginning is a solid base and a way to level/remove any twist from the bed with minimum effort. Without these two, anything done later can and will be undone when they change.

Start with making what the machine sits on as solid as possible. 1st spread the load across as many joists as possible on a continuous "something" solid. It's always a balance between |Good|Quick|Cheap| and generally you can have any two. 2 layers of 1-1/2" press board is a 8' X 4' X 3" base. It won't over load the joists and will resist sag. I'd also consider putting solid cinder blocks under each joist and shim them into contact. This is the same idea as lathe installation guidance on a second floor as was pretty common.

Now you have eliminated what you can towards a solid base. You can retain the square plate, but the factory steel bench is, IMHO, fine.

"If" it has holes in the feet, I'd install leveling feet with long threaded shafts. This is so starting at the foot end, using all grade 8 hardware, you have a nut, a washer, the machine foot, a nut, and then at the end of the shaft, two nuts jammed together. The last nut should be flush or can be a grade 5 acorn nut. FWIT, this is how a Monarch 10EE 3,200 lb lathe is leveled. It is not bolted to the floor.

The nuts above the feet are left loose, the top jammed nut is used to rotate the shafts to level the machine. Then the nut above the foot is tightened.

If you don't have convenient holes in the feet, the idea is still the same, you will have to decide between something similar or shims between the machine and the stand.

Now you have a solid base, and have removed any twist from the bed without having to, hopefully, shim between the machine and the factory stand.

Only after this can you reliably use test bars etc. to learn the nuances of your machine and see what can be altered, and what you will learn to work around.

Just my $.02

I have the tool bench leveled. Im sure a foot with a larger surface area could be installed.
Im not so sure I can get under the building well enough to support the joist more than they are. They are well supported
2x10 16 oc with 3 2x12 running at each end and middle of the joists.
Like a bed frame with slats?
I have 16 8x14 blocks supporting that sub frame. Which sits on top of 16” or so of highly compacted stone and stone dust. Keep the burrowing vermin at bay.
Floor is 1.5” total of underlayment. I suppose at some point I could add another sheet directly under the bench footings under the 12x12x 1/4” plate?

That said still darn near level to the day I set it up over a year ago.
I would need something better than a 4’ Johnson
Today I was messing around with my new inserts and spindle speeds. My lath maxes out at 1600rpm but the finish and DOC is better now with correct inserts and speeds more suited to them.
Any how cutting with a live center. ( I have the tailstock centered to the best I could using a dead center in the spindle and lining up with the live center in the tailstock. I still have a some taper.
.887” at tail stock end and .891” chuck side over 5.5” distance
.004” over 5.5” I dont know if thats good or bad at my level/stage of skill and equipment? I can tell you thats a lot better than when I first got this lathe.


Im not making anything of any length any time soon that would need better, at least I dont think.
Its to cold now and looks like I wont be back out to the shop until spring.

 

[Shiseiji]

Floor is 1.5” total of underlayment. I suppose at some point I could add another sheet directly under the bench footings under the 12x12x 1/4” plate?

That's my recommendation. Spread the load as far as possible, and let the other stuff go. Then do the usual alignment stuff. Get it as dialed in as you can and enjoy using it.

Another "opinion." Seriously consider an investment in a unique HHS tool holder as a one time investment for probably 90% of your work. They are not cheap, but, once the HHS tool is sharpened, it's rare to need more than a hone. It's called a tangential tool holder, a very old design now produced by a single commercial company Eccentric Engineering although with a mill there are a few designs floating around, a couple here I think. Believe me, you will save more by not buying inserts especially for a machine that wasn't really made to use them. I've never heard anyone who purchased a set say they were sorry. You can do a search here to see what others think. Only thing I use inserts for anymore is stainless steel and boring.

 

[tq60]

Your tailstock may not be in alignment.

You need to make a 2 coller spool between centers and use it to align your tailstock.

Get some round stock, 1.5 to 2 inches is good, 3 to 4 inches long.

Face off both ends, drill a center hole in each end.

Start by removing about 1/4 the diameter in the middle, leaving a collar at the ends.

Chane to turning between centers and take very light cuts.

I will suggest a change from normal.

Take light cuts on both ends only until you get a full cut. This now ensures the holes are in the true center.

Measure both and if different sizes, this is the TS error.

Get a dial indicator and place it in your tool post.

Place it on the coller that is at the chuck end, as close to the end as possible, zero the indicator.

Push in the probe and move it to the opposite end and release the probe.

Now adjust the tail stock offset to the zero.

Now take small cuts until you get a full cut on both collers and remeasure.

If the tailstock end is bigger, it needs to come forward, smaller towards the rear.

Place the dial indicator back in thetool post and probe the tail stock coller.

Move it 1/2 the difference.

Repeat until bots collers are the same.

Now save this. You will use it many times, but just use the dial indicator to zero both ends.

Sent from my SM-G781V using Tapatalk

 

[mac1911]

Your tailstock may not be in alignment.

You need to make a 2 coller spool between centers and use it to align your tailstock.

Get some round stock, 1.5 to 2 inches is good, 3 to 4 inches long.

Face off both ends, drill a center hole in each end.

Start by removing about 1/4 the diameter in the middle, leaving a collar at the ends.

Chane to turning between centers and take very light cuts.

I will suggest a change from normal.

Take light cuts on both ends only until you get a full cut. This now ensures the holes are in the true center.

Measure both and if different sizes, this is the TS error.

Get a dial indicator and place it in your tool post.

Place it on the coller that is at the chuck end, as close to the end as possible, zero the indicator.

Push in the probe and move it to the opposite end and release the probe.

Now adjust the tail stock offset to the zero.

Now take small cuts until you get a full cut on both collers and remeasure.

If the tailstock end is bigger, it needs to come forward, smaller towards the rear.

Place the dial indicator back in thetool post and probe the tail stock coller.

Move it 1/2 the difference.

Repeat until bots collers are the same.

Now save this. You will use it many times, but just use the dial indicator to zero both ends.

Sent from my SM-G781V using Tapatalk

Working on a fac

Your tailstock may not be in alignment.

You need to make a 2 coller spool between centers and use it to align your tailstock.

Get some round stock, 1.5 to 2 inches is good, 3 to 4 inches long.

Face off both ends, drill a center hole in each end.

Start by removing about 1/4 the diameter in the middle, leaving a collar at the ends.

Chane to turning between centers and take very light cuts.

I will suggest a change from normal.

Take light cuts on both ends only until you get a full cut. This now ensures the holes are in the true center.

Measure both and if different sizes, this is the TS error.

Get a dial indicator and place it in your tool post.

Place it on the coller that is at the chuck end, as close to the end as possible, zero the indicator.

Push in the probe and move it to the opposite end and release the probe.

Now adjust the tail stock offset to the zero.

Now take small cuts until you get a full cut on both collers and remeasure.

If the tailstock end is bigger, it needs to come forward, smaller towards the rear.

Place the dial indicator back in thetool post and probe the tail stock coller.

Move it 1/2 the difference.

Repeat until bots collers are the same.

Now save this. You will use it many times, but just use the dial indicator to zero both ends.

Sent from my SM-G781V using Tapatalk

looking for a 1.5” + of stock to use.
I have access to axle axle shafts and other automotive parts. I have been grabbing strut shafts when I can. I will get there.