Workshop Log

[propforward]

It's a journey. As always I'm very happy to hear specifics of what I should be doing differently? As I say, next step is look at twist with the machinists level, then try straightening.

[Baner]

There's been some replies as I've been typing, and I see you're going to do it - the lathe must be level before making further adjustments.

Any alignment errors you are seeing at the moment are a combination of bed misalignment, headstock misalignment and chuck misalignment. You need to minimize the variables or you'll start chasing your tail all over the lathe.

Also, make sure the whole lathe is as rigid as possible - if it's not already be sure the stand is firmly on the floor. Concrete is rarely perfectly level and often you'll need shims under the feet. Flex anywhere in the structure will affect alignment and needs to be minimized. 

If you are unsure about leveling please ask, as it is a critical first step for lathe accuracy.

Dave.

[propforward]

Thanks Dave, I appreciate the comments and encouragement.

[10KPete]

I agree with all that Baner said with the exception of level. It may be that the term is used slightly differently than I..??

The bed way must be flat. Level is just so stuff doesn't roll/run/whatever.

Flat is checked on small stuff by putting the part on a surface plate.

Most lathes won't fit on most surface plates! So, we use a very sensitive level to compare one end of the bed with the other end and pray they're both the same!!!

What you do with a twisted bed depends upon the situation....

 

Pete

[propforward]

Well that level is on the way, and I can pretty much gaurantee readings each end of the bed won' be the same. I'll put off deciding how to adjust until I know what the numbers are though.

I think generally in machine tool terms everyone understands "level" to really mean "twist" - or level relative of one end of the bed to the other.

[zeeprogrammer]

Well that level is on the way, and I can pretty much gaurantee readings each end of the bed won' be the same. I'll put off deciding how to adjust until I know what the numbers are though.

I think generally in machine tool terms everyone understands "level" to really mean "twist" - or level relative of one end of the bed to the other.

That's where I'm hoping to get more clarification. As has been pointed out elsewhere...lathes and mill were used on ships. I'm thinking it's all about 'twist'.
Which, to me, seems another way of saying "squareness".

I've recently learned that 'squareness' doesn't necessarily mean 90 degrees but could be 'being in the desired position/location'...like getting a room squared away.

Hm. I recently moved my lathe and now realize I never checked its 'level', 'twist', 'squareness'...or all those things we do.
I've also recently discovered that my new shop floor is not level to earth. Things roll around.

[Baner]

Yep flat is what I meant.

I think leveling a lathe refers more to the tool used, rather than being 'level'. But by the nature of the tool the lathe ends up 'level' by default.

Though saying that I usually shim one side of the machinist level to bring it into range, rather than jacking the whole lathe up... 
 
'Level' is not really an issue for the lathes and machining tolerances in a home shop, as long as the lathe's not going to tip over you should be right.
 
Dave.

[Stuart]

The word level leads to a misconception in this case , the bed must be in the same plane at the headstock and tail stock , and is easily tested with a level .

Ok now the exception to using a level war ships , many large ships have a machine shop on board , so how do you use a level at sea ?


On a mill it’s better to be tangent to the big ball , makes setup easier
On a lathe it helps but not a requirement to the accuracy of the lathe

The method I use is to get it near with a level then do test cuts on a 50mm bar with no tail stock support , this means the bar must be short ,then take the twist out of the bed with the jack screws or if your lathe has jack screws on the HS then use these . Then and only then introduce your tail stock with a longer test bar take test cuts and set over as required


If I need a taper I use a taper attachment ,but before I had that I used a set over tail stock center , and left the TS alone ( hemmigway have a kit for one )

[Ian S C]

With the ??ridgidity of most stands for lathes in a home workshop, the only thing that will move with the jacking screws is the lathe stand, a bit different when the stand was an cast iron structure weighing twice(or more) the lathe its self.
Ian S C

[propforward]

Machinists level arrived.

Headstock end.



Tailstock end



Yep, bed is twisted.

We can fix that though.

Stay tuned for the next thrilling installment of Props workshop adjustments.

[crueby]

I'd blame it on local gravitic anomalies....
 
 

[propforward]

You mean I’m standing too close to one end?

 

[zeeprogrammer]

You mean I’m standing too close to one end?

 

Stand next to the other end and see if changes. 

If it does...you're in a world of trouble my friend. And that's spelled with a 't'.

[propforward]

Or trouble spelled with a capital S.

 

Well anyway, the weekend can't get here too soon. I want to try adjusting things now.

If the cabinets are too flimsy, and I can't straighten the bed out, or if it doesn't hold over time, then I may have work waterjet me out some 1/2" thick steel plates to beef up the cabinets a bit. I don't get those for free though, so I'll try as is first.

[zeeprogrammer]

What is that measurement? 2 ? over what ?.

If I understand correctly...you set the level across the ways at one end and then some distance (other end)?
I ask because I want to know if I did it right.
It looked like mine had no twist...but I don't know if I measured correctly.