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Putting right my tailstock DRO.

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bogstandard:
Thanks David.

Darren,

If you look at the original two pictures at the very start of this topic, you should be able to envisage how it works.

Before I start on the tailstock drilling, I will make up a mock up, to show you how easy it would be for you too to have accurate tailstock drilling.

John

bogstandard:
As promised, here is a mock up of how easy it is to put a DRO on your tailstock.

It is in fact a tiny bit more involved than this, but basically it consists of a chopped down digivern (you can grind off all the sticky out bits), something to lock around the nose of the ram and you would need to make up either a sliding joint as I have or something like a small conrod to join the nose clamp and the digivern together. You need that joint between the two, because the digivern will be fixed rigid and the ram is guaranteed to have a slight rotation in the tailstock. If the joint isn't there, your read head would soon end up bent and buggered.




Anyway, back to fixing my bit.
By trying the slide I made yesterday and the read head onto the top of the tailstock, plus some very accurate measuring of bearings in slots, I got the layout of where the bearings should be located.




The first thing to be done was securely clamp the tailstock onto the mill table, and by running a DTI along the ram, I got the ram perfectly parallel with the table.




Using the edge finder, I soon had the position of the first datum point. I wasn't worried that I was taking a reading off a painted edge, as it wasn't too critical where the first datum ended up, a few thou either way isn't going to cause any problems at all. The critical measurements are all taken from that first datum point.




At that datum setting, everything was zeroed up.




Before you all start screaming about using a milling cutter in a drill chuck, which is a very bad practice. This time only, all I am doing is skimming thru the paint layers and a superfine skim on the casting. These are going to be where the bearing spacers sit down onto.
If you notice my previous effort on the side of the tailstock, you can see where the spacers had cut thru the paint by themselves. This time, with a little more foresight, I am doing the job correctly.




The holes were soon centred and drilled for tapping to 3mm.




Then quickly followed down with the tap. Even though it isn't really necessary in cast iron, I did give each threading cut a touch of cutting oil.




With bearings tightened into the newly cut holes, the slide was tried for fit.

Even though I am running mainly on the bearing edges and faces, the slide is incredibly smooth in operation with no detectable side or up and down end float.

That will do me for now.



It took a fairly long time to get these four holes drilled and tapped, but this is a critical part of the setup, getting this slide running perfectly in line with the ram.
Besides, if a job is worth doing, you should do it to the best of your abilities and facilities.

All further fitting and drilling of this part of the mod will be done on the lathe, freehand.

I am sorry this topic is coming in short sharp bursts, rather than my usual long posts about hours of machining. At this time, I am only able to grab a few hours here and there.


Bogs

CrewCab:
Take your time John, as usual it's enjoyable and informative  :thumbup: look forward to more when you get the opportunity .............. take care

Dave

Bernd:
Nice job so far Bogs.  :thumbup:

I'm getting a few ideas with that slide you made with the bearings. That idea can come in handy for making a few things I have in mind.  :dremel:

Bernd

bogstandard:
Bernd,

The slide I am using here is really designed for its original location, working in a vertical position not horizontal as it is now.

The way it is being used here is in fact incorrect, the bearings should be upright in the slots (with wider slots of course) but for the use I am putting it to, it will be just fine. There are no heavy loadings on it at all, and it is doing the job.


Bogs

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