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Question What happens if you grind both the bed and carriage of a lathe and no more

I don't mean any disrespect, I realize the OP is from Holland so maybe it's a translation thing, but I really don't understand the question. If you grind both the bed and carriage, no more what????

What will be the result?

Well, for starters, unless it's a box way machine it's gonna be tough to grind it such that you have even bearing on all surfaces. Even then, the gib will need to be fitted, tough to do with grinding, but possible I guess.

I think most important will be the lube system. Pressure fed lube, hydrostatic???The surfaces will have 100% contact so they will want to wring out the oil film and stick together. Your lube system will need to be designed to overcome that.

I know some machine makers have tried this sort of arrangement, I'm no expert on the results or exactly what you need to make it work.
 
The Chinese do it all the time It may not be ideal but? If you are` after ultimate it is probably not best to start with reworking worn machine . If not go for it and find out report and back
 
Not enough information Peter. Is it a new lathe or a recondition job ?

Just stating the obvious but having two highly polished surfaces running together isn't a great idea unless your lube system is 100% efficient.

If it's a rebuilt lathe you'll have to correct the misalignment of the apron gearbox and the feed box - tail bracket, plus the feed rack will need re-aligning.

Regards Tyrone.
 
How about a fractal oil delivery groove network such that no point on the sliding survace is more than .1" from an oil groove.

Even better would be to make a network like how blood vessels are, pumping way oil through gives an exit for the contaminates.
 
I mentioned it to someone who has a rebuild 135 ( by ruemema) and to my zurpri e he told me the carriage of a 135 was not scraped at all but it was ground with a certainfinish
How about that Can I believe him you think
 
Title says it all
Just lubrication off coarse No scraping
I ask with a specific reasson which I tell later

Peter

In the normal course of events? Two things:

- The Headstock and tailstock (or turret), if any, may remain aligned if, for example, on a Hardinge (style) dovetail bed. On prismatic inverted-vee ways, both will need refitted.

- A carriage apron's coupling to leadscrew, power surfacing shafting, and any operating control rods will be mis-aligned, low.

Not all lathes have all, or even ANY of those. Or even a carriage. Others have more than one carriage.

Still others have independent height ways. Or linear rails.

And then there exist "tee" lathes.

So, Peter? Was this meant as a "trick" question?

EG: MUST one scrape?

No. Not always. Just "usually".

:)
 
I mentioned it to someone who has a rebuild 135 ( by ruemema) and to my zurpri e he told me the carriage of a 135 was not scraped at all but it was ground with a certainfinish
How about that Can I believe him you think

Absolutely.

And it is probably NOT a "mirror" finish, is it?

Just enough "coarseness" to provide for oil retention as a byproduct.
 
Why don't you use your machines instead of endlessly obsessing about them?

We put a man on the moon without a single Schaublin. Can you believe that? I wonder if NASA inspected the carriage scraping on every lathe their suppliers used.

For your information
We are in the reconditioning part of this forum
Not done to talk about "using" your machines over here

Peter
 
I would imagine if the bed is a V design, they may not match as you have at least three surfaces all at different angles and heights to grind correctly. That is if you want top of the line quality.

You can get away with doing it though.
 
Every Schaublin 135 I had had a real drag on the carriage
It makes sence if you dont have a scraped surface
You get stick slip But thats oil between the surfaces No direct metal to metal contact
So how good or bad is a stick slip for the lifespan of a lathe
Good perhaps ?? Less wear ??
It looks like it, I at least never saw a 135 with really bad ways
Downside is then you have more drag
The challenge is to match all surfaces to a high standard
Opinions please
 
many precision surfaces are machined with lubrication grooves and or scraped with a oil retention pattern.
.
on a printing press the mirror finished cylindrical rollers i would cross hatch the hard chrome plating with 220 grit sand paper in a diagonal X pattern that would hold enough in the grooves made by sandpaper to provide micro lubrication and it worked 10X better. but it wears off after a few months
.
a machine precision scraped oil retention pattern often will last over a decade and is often closer to .001 or .002" deep. seen plenty where its worn down but it takes a long time
 
I am sure the boys at Schaublin know how to scrape
But they saw a advantige in just grinding it then
For those of you who don`t know
The Schaublin 135 was a top end machine Cost nor labor were spared to make a high end machine

Did they have some secret finish on the carriage ?? Dont think so

Its not easy to grind it to such perfection that the carriage/bedway assembly rides within 0.002mm (note mm not inch) or less
Not easy at all
Can anybody confirm the carriage is not scraped???

Peter
 








 
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