What's new
What's new

Powerturn, has anyone tried reversing the ways?

gbent

Diamond
Joined
Mar 14, 2005
Location
Kansas
I've a 21" Powerturn with the typical wear next to the chuck. Has anyone ever tried unbolting the ways and flipping them end for end?
 
Don't know about the Powerturns but I had asked the people at LeBlond years ago about replacing the hardened ways on a Regal.They had some stock on hand but told me it was installed and then ground in place. If that is the same with the Powerturns then your results may not be to good.
 
If you could, that would still leave the issue of way surfaces of carriage. I would expect equal or multiple times worse wear on carriage.

I'd be curious if both ways for carriage are vee ways, and if so, if one bed vee way surface wore more than the rest ? If it is predominately one surface, might not be terrible to remove that way, have that surface ground. Then work the carriage to fit.
 
I recall dad talking about them reversing the way inserts on one of the lathes they had in the shop. Sorry I don't recall the brand, If I had to guess it was either Lodge & Shipley or Lehmann Lathes they ran in the shop. End results, wasn't a great accuracy of change, but got them another year or two of use until the machine was sent out to be rebuilt or scrapped. Have to remember, the product they were producing on these lathes did not have to be made to a degree of accuracy. Most of everything was +/-.015". I know they bought way inserts to install on some of the machines, too. But as others have said, the way inserts really need to be ground in place for upmost accuracy.
 
It’s been a pet peeve of mine that hard replaceable ways are not actually very replaceable. Always need ground in place or fitted carefully or anointed by the priests of the First Unified Satirical Church of Precision.....

If I were King, the bare beds would have been scraped to 0-0-0, then a standard hard way would be attached. Time comes for rebuild could order standard replacements OR grind old ways straight down say .020” then grind saddle straight down .018”, install hard ways with a .040 or .020” shim and have .002” scraping allowance in the saddle.

Wallah! No turctite needed.


Sent from my iPhone using Tapatalk
 
I've a 21" Powerturn with the typical wear next to the chuck. Has anyone ever tried unbolting the ways and flipping them end for end?

Been done. Been seen. "Right here, on PM". Fotos may or may not have survived.

Rather a long count of years back, there was a L&S of just about that swing for sale in Kamloops, BC, Canada.

Fotos showed that the replaceable ways HAD BEEN reversed and were sticking proud several inches into free air at the TS end... with a gap at HS end.

That was due to the mountings not being made for mirror-image reversal.

It had been in-service that way for some years, though.

IIRC, a Canadian PM member did eventually buy it, too.


Whether reversed or fitting new (old stock), one significant challenge (s mentioned, above) was getting rust UNDER them cleaned-up and their seat made true as can be. That was covered on PM as well, ISTR it was a different lathe?

So there was hand scraping and sore TEDIOUS fitting to do after long years of hidden rot, even if NOT required to have the whole bed and ways assembly put under a bedway grinder post-install. As it was not.

Pure guess, but whomever came up with the idea of replaceable "tool steel" ways seems to have:

A) Expected an environment of low/no corrosion "neat oil" for cutting fluid AND NOT a water-emulsion.

B) Not realized that replaceable or never, "tool steel" ways were likely to outlast any significant value as the REST of the machine would be sore wore-out by the time the ways were up for replacement the first time ... and probably ONLY time if-even they WERE to be replaced, ever.

Accordingly, damned few ever were replaced. Damned few makers ever copied the idea.

Bedway grinding didn't even get done to "commodity" lathes all that often.

He who was in need of it might be the fifth owner.

- "Desperate-poor" had a hard time affording it.

- "Wastrel-Wealthy" just disposed of it, bought a whole lathe, brand new.

- "We chikn's" in between?

Have to do some serious pondering over just how much money, labour-time, DOWNTIME, sweat, and RISK, can be justified over simply running what we got (as always..) and compensating for its flaws.

Bottom line is that any hand good enough at his craft to correct bad wear is also a hand good enough at his craft to JF make good parts on wore-out machines without NEED of correcting the wear.

Eventually we chick'ns just trades for a whole 'nuther machine with less wear.
And do not waste a lot of resources fixing up THAT one, either.

Not exactly a "new" compromise, is that?

Prolly started with recycled Roman Army bustid swords made into early-eyetalian "Bowie knives" and wearing used hob-nailed combat sandals 'stead of going barefoot?

"Run (on) what you got!"

Caligae - Wikipedia

:D
 
It’s been a pet peeve of mine that hard replaceable ways are not actually very replaceable. Always need ground in place or fitted carefully or anointed by the priests of the First Unified Satirical Church of Precision...........................

There is proof in the Lodge & Shipley catalogs and literature where the bed precision planed and the harden & ground way inserts are ground on fixturing on a large grinder. Probably done on a Mattison grinder. Then the inserts are assembled on the bed.

I do agree, the only right way to do this is bolting down the harden ways to the bed and then grind. All the rebuilding I've done in my past and seen done, the bed ways were reground in place. Replaceable ways were never removed and ground. The main reason those surfaces are not scraped to a degree of flatness and bearing, is that adds lots of unnecessary cost to the machine tool. At least, this is how it was looked at back in time. Now days, machine tools with linear rails, the pads these rails are mounted on, they are scraped to some degree of precision. But you pay for this as part of the cost of the machine. The more precision you ask for, the more it will cost.

Sorry for getting off subject here.

Ken
 
Good commentary Ken and I’m sure you’re right about the cost difference.

The dichotomy of building very fine machines with no expense spared AND not taking this final step is the source of my peeve.

Plus, when I go out and buy a 60 yr. old machine for a tiny fraction of new price in constant dollars, I expect everything to be “good as new”! Someday.....


Sent from my iPhone using Tapatalk
 
Now days, machine tools with linear rails, the pads these rails are mounted on, they are scraped to some degree of precision. But you pay for this as part of the cost of the machine. The more precision you ask for, the more it will cost.

Not really as bad as all that.

What has happend with linears is that THREE functions that were ONE shared function on solid ways have been severed:

- the linear"s "cartridge" precision bearings cover the need for what HAD been a sliding fit. But you can lift a cartridge with two hands if not but one. The precision is built into it "somewhere else" in a specialized factory. Not generated right ON the casting as conventional ways had to do.

- the rail provides CONTINUOUS (and smooth) alignment. But cannot stand alone in free-air, however..

- the PADS that provide that support no longer need a bedway grinder larger than the machine tool. They can be "made right" off the back of milling, then uber-high precision PORTABLE metrology, scraping, molded compounds, and/or precision shims.

The result is not only as good or BETTER as Vee or rectangular bedways, the seals on the bearings give it a long service life for any chosen level of precision.

Annnnd..

No longer needing the massive grinder, it can be field rebuilt, once again with high-grade but eminently PORTABLE metrology. Lasers and such, not ten-foot camelback SE's

Because EACH pad only has to be where it needs to be and is done one after the other.

No need to run a grinding wheel down the whole row in one pass, repeated.

There STILL must be a source of stiff load-bearing UNDER that whole row of pads. But it can NOW be a weldment, not "just" a massive casting.
 
thermite,

I was referring to the linear bearings/rails used on DMG-Mori machines. According to my source, you specify degrees of precision in those rails and bearings. Yeah, you want to hold repeatability in millionths, they will provide it and certify it, too. But you will pay dearly for it!

Ken
 
thermite,

I was referring to the linear bearings/rails used on DMG-Mori machines. According to my source, you specify degrees of precision in those rails and bearings. Yeah, you want to hold repeatability in millionths, they will provide it and certify it, too. But you will pay dearly for it!

Ken

Familiar. What I RUN is what I can comfortably afford and actually f**k around with.... to no particular goals.

What I "keep an eye on" is bleeding edge. Because I can.

Warms the bean-counter's heart what modern CNC is capable of.

But it pays better to own pipeline operators. Y'have any idea what the barriers to NEW rights-of-way are these days?

See ETRN or AM. Check the dividend percentages - thousand share blocks...

"Retirement" gets any more complicated than that, I'd want...

faggeddabouddit!

It ain't.

Gittin' any more complicated!

:D
 








 
Back
Top