Rebuild - No 3

[olaf Vogel]

So for a while, I've obsessed about a few short comings on my old lathe.
And once it became apparent that I needed to repour my babbitt bearings, I took a wider view to rebuilding the beast.

As you can see from the title, there have been 2 prior rebuilds that I have done.
Over the 140 year lifespan of this lathe, its gone through many changes. This being the latest, but not likely the last.

So, short comings:
- rigidity at the headstock
- power at lower rpms
- ability to run backwards - so I didn't have to bend way over when hollowing.

That all led to a new design direction:
- faceplate only - no thread on chucks, which allows this to be reversible
- MUCH heavier
- lower gearing.

I bought some giant pillow blocks and had a local machinist turn the spindle for me.

Some initial (teaser) pics are here:
http://www.owwm.org/viewtopic.php?f=1&t=198182

All of which will likely generate more questions and comments than I can answer tonight.
But the project is proceeding and going well. A few more weekends and it should be spinning again.

 

[RichColvin]

I enjoyed building my ornamental lathe, but I’m glad I didn’t build my traditional lathe. Good luck as you progress. Your knowledge of the building process will make you a better user..

Kind regards,
Rich

 

[John Torchick]

Nice project. Looking forward t o seeing the completed project.

 

[Donovan Bailey]

It is truly astounding that you are taking on this project...not to mention the effort and technical knowledge that it has taken to put/keep life in your monster machine. I wish you the best and certainly look forward to hearing about your progress.

 

[Emiliano Achaval]

So for a while, I've obsessed about a few short comings on my old lathe.
And once it became apparent that I needed to repour my babbitt bearings, I took a wider view to rebuilding the beast.

As you can see from the title, there have been 2 prior rebuilds that I have done.
Over the 140 year lifespan of this lathe, its gone through many changes. This being the latest, but not likely the last.

So, short comings:
- rigidity at the headstock
- power at lower rpms
- ability to run backwards - so I didn't have to bend way over when hollowing.

That all led to a new design direction:
- faceplate only - no thread on chucks, which allows this to be reversible
- MUCH heavier
- lower gearing.

I bought some giant pillow blocks and had a local machinist turn the spindle for me.

Some initial (teaser) pics are here:
http://www.owwm.org/viewtopic.php?f=1&t=198182

All of which will likely generate more questions and comments than I can answer tonight.
But the project is proceeding and going well. A few more weekends and it should be spinning again.

That lathe is nice! Well worth the effort to keep her going. Good luck.

 

[olaf Vogel]

Here's a quick update from the weekend. Unfortunately, due to commitments with work, family etc, this project has been slooooow.

My original mounting (and alignment) idea didn't work. It required alignments in X & Y, as well as keeping the pillow blocks parallel (in a separate set of X & Y, that were tilted about 45d). There was just too much going on, that needed to be aligned, all concurrently.

The theory wasn't bad, since the bearing are self-aligning, but when the shaft is 3" OD, any small error in alignment was too much and the shaft would bind.

So I simplified things and mounted the blocks onto a steel plate, 3/8" thick. I aligned the two pillow blocks so the shaft spun nicely. Initially I epoxied that blocks onto the plate and let that sit for a week.

That allowed me to move the plate around, onto the drill press, so I could drill the holes - without anything moving.
That was an adventure as well. Try drilling 12 holes, precisely, that are up to 5/8" dia, through a 3/8" steel plate. And that assembly weighs a fair bit.

Once the assembly was in place, the trick was to align the plate with the tailstock: X & Y when the tailstock is up close. Thats not hard.
But also still aligned when the tailstock is 5 feet back. Thats tricky.

So I've installed 4 vertical rods, that mount on the bed. These support the plate and allow very easy & precise X axis adjustments.
Then (not seen) are two horizontal threaded rods, to the back wall, that allow Y - axis adjustments.



Simple - I was able to dial this in after about 30 min.
It was straight and parallel with the bed, with the tailstock all the way back, I was off only about 1.5 mm.

Now the next step is to build a concrete form, of plywood, around the mechanism. And add some rebar. I'll leave that for next weekend.
And the physically hard part of mixing and pouring the concrete (I'll have to wait for warmer weather and bribe a few friends with lots of beer)

So all those rods will be encased in concrete. Most of them have large washers attached, which will also be encased.
Each pillow block has 4 rods holding it down.

So...sharp eyes will notice, "why the springs?" on the 4 main rods?

Well, I found it very difficult to adjust the nuts above the plate and below to the exact spot.
Moreover, I want the flat plate to have lots of contact area with the concrete underneath.
So the plan is to raise the plate, fill in concrete below. Then tension is up again, (lowering it) so it squishes down on the concrete. I can't do that if there are nuts underneath. And once the concrete has been poured, those springs won't bounce any more.

The drive mechanism is attached and running.

Getting closer....I really want this running by spring. There's a huge pile of wood under that snow!