How do I solve this?

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Davo J:
If your measurements are right that means the block is leaning back toward the column at the top, so is not caused by sag as it would be the other way. Bridgeport's make the knee high from factory but that is only around a thou, but your seems to be much more.

If you Y axis is not worn much you could try winding the table forward and placing the block directly on the Y axis way and start from there up.
Do as suggested and make sure your gib is snug, but it's a case of starting at the bottom and working your way up to see where the fault is.
Something that can throw thing out is swarf caught under the saddle as well so you really need to take things apart and give it all a good clean up and go from there.

Dave

Fergus OMore:

--- Quote from: Anzaniste on January 22, 2012, 08:14:14 PM ---
FOM. Thanks for pointing me to the book, I've actually got a copy on my book shelves and hah forgotten how much of that kind of info was in it.

--- End quote ---

There's a lot there! Two more sets- one is that great tome called Machine Tool Reconditioning by Connelly. Bloody expensive, appallingly heavy but you could possibly borrow one from a public library. Your nearest- perhaps is Gateshead! There was a copy there.
Again, you want a copy of Holzapffel. I think that it is a freebie.

As I can't count, here is a third. It is Georg Schlesinger's book on Machine Tool testing.
Newcastle upon Tyne HAD a copy.

Maybe a fourth? Well, why not? Ned Westbury as Editor of Model Engineer wrote as Geometer and I do recall some of his writings still appear about alignments- they were on the net.

However, I think that the result of the obvious examinations should be recorded. As two planes on sliding bits of machine tools wear, have you removed the gib and checked the parallelism or what is left by two cylinders and J Blocks or what you have as substitutes?
One side, that is the side that the gib was fitted should be unmarked but what about the working side? Again, turning to the gib itself- have you miked it for parallelism?

To be sure, there is a lot to do. Maybe there is a time to refresh skills such as blueing and scraping slides.

cheers

Anzaniste:
I've obviously got a lot more serious measuring to do but I will have a go at the gib strips first.

I am at a loss to find out what a J hook is. :(

As highlighted by FOM I obviously am lazy at turning to to my own reference library so I have made use of my bookshelf and looked in Connelly, Robert H Smith, Machinery's Hand Book, three books I have on metrology a couple of different Engineers Hand Books even an ancient Herbrt's tools catalogue, nowhere can I find reference to a J-Hook. :coffee:

Googling has produced no answer!!

What is a J-Hook?? :scratch:

I'm off to the shed now to fiddle with my gib strip!! :wave:

DMIOM:

--- Quote from: Anzaniste on January 23, 2012, 09:23:39 AM ---.....
I am at a loss to find out what a J hook is. :(
......What is a J-Hook?? :scratch:
.....
--- End quote ---

I don't know what a J-hook is in this context - neither to be honest do I know what the "J-block" FOM referred to is either!

Dave

Fergus OMore:
Ah, a J Hook? I've suddenly had a bit of the Aurora Borealis( yep, it's supposed to be over Newcastle tonight again)
I reckon it is not a 'push scraper' but a pull scraper- beloved of Ian Bradley and Norman Hallows- writing as Duplex.

Of course, since Connelly, there is such a thing as epoxies and fillings of metal. You could fart about with a bit of Devcon to find if there are 'hollows' not Hallows. I used a bit of Loctite 660 for some job on a leaky Myford Super 7 early oiler.

Do I take the prize but what I had for today's breakfast I've forgotten.

Oh, and a J Block is a Johannsen gauge block

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