Workshop Log

[b.lindsey]

Nice looking level Stuart. Great addition to the toolbox even if not used regularly.

Bill

[propforward]

Zee - the specific measurement doesn't matter so much - basically the gauge needs to read the same each end of the bed. Again - being "level" isn't what's important here - being flat (along the bed) is. I'm not about to take the time to get the bubble in the middle of the gauge at each end, I'm just going to match the tailstock end (picture 2) to the headstock end (picture 1).

On Saturday, when I get into this, I'll position the level carefully and record what I'm doing, and post about it. Tonight was a quick placement to see what I have ahead of me. This looks to me like I should be able to use shims to get the twist out.

[propforward]

Nice looking level Stuart. Great addition to the toolbox even if not used regularly.

Bill

Thanks Bill - I thought so too. Plus I can use it to get my turntable set up properly as well. I went back and forth about the expense, but being able to keep an eye on the bed over time easily is a nice facility to have.

[zeeprogrammer]

The precise measurement doesn't matter so much - basically the gauge needs to read the same each end of the bed. Again - being "level" isn't what's important here - being flat is. I'm not about to take the time to get the bubble in the middle of the gauge at each end, I'm just going to match the tailstock end (picture 2) to the headstock end (picture 1).

Understood. You want the same reading, whatever it is, at both ends. I was just curious to know how much twist those readings meant.
As I said before, you're my guinea pig  so I can learn to improve my own machine's accuracy. 

No pressure. 

[propforward]

The precise measurement doesn't matter so much - basically the gauge needs to read the same each end of the bed. Again - being "level" isn't what's important here - being flat is. I'm not about to take the time to get the bubble in the middle of the gauge at each end, I'm just going to match the tailstock end (picture 2) to the headstock end (picture 1).

Understood. You want the same reading, whatever it is, at both ends. I was just curious to know how much twist those readings meant.
As I said before, you're my guinea pig  so I can learn to improve my own machine's accuracy. 

No pressure. 

Well, each graduation represents 0.005” out of level per 12” of distance. I will make an initial judgement of shim thickness to try based on that. Got to start somewhere. After that......

I hope I don’t disappoint! The pressure is on. I’ll psych myself up for a few days.

[10KPete]

After you check each end I would recommend that you release any fasteners holding the bed to legs, bench, etc. and see what happens. If you must apply forces to straighten the bed you'll want to know the real adjustment needed.

Pete

[Baner]

I’ll second Pete’s advice. Lathe beds usually spring back to level when the fasteners are released. Twist tends to be the fault of flimsy sheet metal stands, on this size of lathe anyway.
Also, Feeler gauges are a cheap source of a large range of shim stock, handy when you need to make super fine adjustments to lathe levels.
Dave.

[propforward]

Yes indeed, that sounds like a logical approach, that's what I will do. Thanks for your input!

[propforward]

One of these arrived during the week.



Should be useful for some general tasks. Available from all the usual import machinery places for the same price.

Anyway, enough of that. I know you are all gagging to know about the exciting adventures of lathe alignment.

So off we go.

First off, I loosened all the bolts securing the lathe to the stand, and placed the level at headstock and tailstock ends.

Headstock:



Tailstock:



Would have been nice if they had read the same, but it is what it proverbially is.

Since I had everything loosened up, I thought I'd make an attempt at levelling the lathe crosswise, as well as straightening it.

At one point, I was nearly there.



However - the truth is that the stands that came with the lathe are flimsy, and just as predicted by several folks, it is damned difficult to get the machine to behave.

In the end, after much shimming, I decided to abandon the crosswise levelling somewhat, and focus on removing twist.

It took a lot of work, but at the end the scale read as follows:

Headstock end



Tailstock end



Now tell me if you think I'm wrong, but honestly I think that's as close as I'm going to get it on these stands. You have to overcompensate with shims, to deliberately bow the stand some and still apply twist to the lathe. I don't have a lot of confidence that this will stay put over time - so I'll keep checking it periodically - but I think this is going to have to be acceptable for the time being. A future project may be to fabricate a really solid welded square steel tube frame.

In the meantime, on to the test bar.

[b.lindsey]

That looks pretty good to me! Nice addition on the little sander too. That should be handy for lots of things.

Bill

[propforward]

So here is my test bar - 1 1/2" diameter, with 8 1/2" of length available for turning.



I took a very light skim cut along the bar, a couple of times until I was certain I had turned the whole diameter all the way along, then measured the bar at the headstock end, center of the machined portion and far end of the machined portion. Measurements were taken 4 times in each place, rotating the chuck 90 degrees between each measurement, to get an average for each position.

Here are my results:



The red number is just becuase I picked up a different pen.

Averages

Headstock - 1.4668"

Center - 1.4659"

End - 1.4645"

So approximately 0.001" of taper per 4"

That seems a bit much. So now I'm psyching myself up to attempt a headstock alignment.

[Baner]

Stuart, it looks like the bubble in the level is sitting at maximum travel. It may not be indicating level. The bubble needs to be within the red lines to be reading true. You can shim the level on one side to bring the bubble into range. Just make sure the shim is placed at the same point on the level on each reading. 

Dave.

[propforward]

That looks pretty good to me! Nice addition on the little sander too. That should be handy for lots of things.

Bill

Thanks! I really don't see getting it any better.

I keep running into little clean up jobs where I think a sander will be less agressive and easier to use than a grinding wheel, and hopefully a little better than a hand file.

[propforward]

Stuart, it looks like the bubble in the level is sitting at maximum travel. It may not be indicating level. The bubble needs to be within the red lines to be reading true. You can shim the level on one side to bring the bubble into range. Just make sure the shim is placed at the same point on the level on each reading. 

Dave.

I'll double check that immediately, but if you look at some of the other pictures you can see the bubble can disappear way off beyond the visible area of the scale.

Didn't think of shimming the level though to get better readings - that's smart. Back off to the shed. If the level reading is still satisfactory then I'll be looking in to removing the taper.

[Baner]

My bad Stuart. Just went and checked my level, (same as yours) and you’re right, the bubble does travel further. Sorry, I’ve been tripped up on that problem before, it looked like it was happening to you too.

Dave.