Author Topic: Lathe mods  (Read 4251 times)

Offline mechman48

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Lathe mods
« on: August 24, 2015, 03:00:40 PM »
Hi all  :wave:

For those with Warco WM250 V-F lathe you may find this helpful; got round to my toduit list & set to making a new compound slide gib key; the original provided was an abysmal piece of mild steel, obviously hand ground at the manufacturers, why it took me so long to do a new one is beyond me; probably down to the 'get your finger out ' not being to the fore front... dont know , any how made a new one from brass, the original was a piece of MS roughly, & I mean roughly 3.4 mm strip, that should have been a decent fit into a 5mm gap. I made the new one 4.7mm which slid in nicely giving enough gap to nip up neatly. As you can see the original bore no resemblance to a proper gib key shape, also the undercuts in the dovetail corners were far too big, reducing the width of the bottom mating face, looks like the Chinese machinist picked up the nearest slitting saw to hand & whacked that through, undercuts half the size would have been more than enough & would have allowed more bearing surface on the bottom slide, anyway I now have a much neater fitting compound slide with no tight spots when adjusted & now moves nice & smoothly when I wind the slide back & forth...

The OEM gib key...
gib key mod (1).jpg
OEM 'gib'... couldn't even get the angles correct...
gib key mod (2).jpg
Piece of scrap steel ?...
gib key mod (4).jpg
Machining new brass key...
gib key mod (8).jpg
New key, much better fit, although dovetail undercuts way to big!
gib key mod (12).jpg
Also modified the locking screw...
gib key mod (16).jpg


That's another 'mod' off my toduit list...

George.
George.


Always look on the bright side of life, & remember.. KISS..' Keep It Simple Stupid'

Offline Jonny

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Re: Lathe mods
« Reply #1 on: August 24, 2015, 04:15:46 PM »
Shouldn't be any undercut in the dovetails, flats on the peaks of opposing joints yes if need be. Its done that way because its easier and quicker to machine the castings and with far less dovetail cutter wear.
Check left of picky top slide bottom edge well off flat before and after. Should also sit on those flats and pull in to dovetail and down via the gib strip.

Offline velocette

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Re: Lathe mods
« Reply #2 on: August 24, 2015, 09:24:19 PM »
Hi Mechman48
Depend on if you wish to improve this more
Machine a "Cup Point" on the adjuster screws and insert a bearing ball <O> to give better small contact on the gib.
See attachment
 Remove metal @ "B" with a "Fly Cutter"  not to exceed the gap @ "A"

More info on this topic at
http://madmodder.net/index.php/topic,7324.msg78471.html#msg78471

Eric

Offline Fergus OMore

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Re: Lathe mods
« Reply #3 on: August 25, 2015, 02:32:17 AM »
I've just fitted the 'George Thomas' modification of a pinned gib to my Myford top slide. I fitted one to my Myford vertical slide years ago. I'm pleased to see that others agreed.
Mind you, following the original poster- There is lot to be said for 'actually filling' the empty space with shills or something like Moglice or Devcon.- if you can't fit a gib that takes up the whole of the gap.

Thinking about gibs, Myford on their Super 7 fitted adjusters to TWO parts of their gib i.e. top and side on the cross-slide.

Norman