Rollie's Dad's Method Help?

[customcutter]

OK, I've read several threads on "leveling" a lathe, and I understand it's not necessary to level, just necessary to get everything in a horizontal plane.

My question is, is RDM for aligning the headstock with the ways, and tailstock? Horizontal and vertical alignment by adjusting the headstock? Or is he talking about shimming the "feet" of the lathe in his discription to achieve alignment?

My lathe is a 14X40 so I only have 4 "feet" instead of six for larger lathes. I guess I'll start by making some "jack bolts" to insert under the "feet".

thanks,
Ken

[TGTool]

RDM's method is just about eliminating the twist in the bed - shimming adjusting the feet. Visualize an imaginary line that's the lathe spindle centerline projecting straight out down the bed towards the tailstock. Now imagine that the bed is a little twisted as though the tail end was unscrewed. As the carriage progresses down the bed towards the tail the tool is going to be pulled a little away from the centerline and just a teensy bit down. That's the quality that the RDM method is trying to measure and allow you to correct.

[.RC.]

I would not use "rollie's dad" method on any lathe other then a very light bench lathe like a small short South Bend..

IMO using that method on a larger lathe is useless..

[customcutter]

Just checked my lathe using RDM. Using a 30" hydraulic cylinder ram that measured 1.001" on both ends. I got .004" of run out in the horizontal measurement, and .006" in the vertical.

Being I just got it back into position I think I'll let it set for a few days and settle in before trying for anything better.

Also only got .0005" run out on the 3 jaw chuck. Very happy with that, I wonder if it is the original Taiwan or aftermarket. I'll have to check.

thanks,
Ken

[J Tiers]

RDM can measure the twist, IF you already KNOW that the headstock is aligned.

OR

RDM can measure the alignment of the headstock, IF you already know the bed is level / not twisted.

RDM is all "internal", all "self referencing". You need an external reference, like a level, to do the whole job.

In fact, RDM is just a fiddly and error-prone replacement for the "two collars" test, and to make matters worse, it is not a test of actual operation (which the collars test IS).

Don't make the mistake of thinking it is magic hidden knowledge of some sort. It's just a test of the relation of spindle axis to bed, and probably not the best one, at that.

[Forrest Addy]

The RDM has its vociferous adherants but in fact it's a waste of time advanced by the ignorant but enthusiastic to - in all good faith, BTW - innocently deceive the ingnorant but equipment poor. The RDM seems simple and effective - and it is in a limited way - but most of its appeal lies in the hocus-pocus facor. By the time you go through all the interations you still don't know what you have. The RDM is time consuming and non-quantitive, except in the final cuts.

There is one inescapable fact about the Rollie's Dad's Method: no skilled equipment re- builder, millwright, production or job shop, or manufacturer uses it or any method like it to align their machine tools.

The next question is: if no competent craftsman uses RDM, why should you?

A level, a two collar test or proof bar, basic mechanic's tools, etc, and cutting tests yields the best results in aligning a lathe to "test sheet ready " in the least time. If you don't have this minimum equipment, round it up. You will need it for annual checks and new machine installations anyway even in the home shop. With these one man can set up and align a new lathe 20" and smaller to factory specs in a couple of hours, and a worn lathe to best compromise in 4.

[Paul Alciatore]

I believe I was the one who suggested "searching for Rolleys Dad's Method" in another thread. Perhaps I should have been more specific. I said to look it up, but I did not say to actually use it. You will find a great amount of information in those posts, much of it better than RDM. I am sorry if I caused any confusion.

[Forrest Addy]

Paul. I kinda gathered that when I skimmed your response. However mention of RDM in any contest seems to bring its adherants out of the woodwork and I wanted to scotch building enthusiasm. Hence, my red-eyed vigor.

If my words put you in a bad light, I'm sorry. That wasn't my intention. Call it friendly fire.

[customcutter]

I did a search last week of this site and I think the key words were "lathe level" or "lathe leveling".

There was a lot of discussion on 3-4 threads about the lathe not actually needing to be level at all "lathes on ships, etc." However it was simply a means a putting everything into a measureable horizontal plane. I understand and agree with all of this. However, in one of the post RDM was mentioned and the method seemed simple enough, and seemed to make sense. Since then I have read other post in other threads/forums and looking for some advice on whether it was meant to shim the headstock or shim the feet of the lathe? Not trying to start a heated discussion. Never realized that as some have said that it is for "mini-lathes".

I'll look up the two-collar method and see what that involves.

thanks,
Ken

[customcutter]

Did another search on the "two collar method" trying to digest everything for now.

I'll start by leveling the lathe and work from there.

thanks,
Ken