I've got a new CVA lathe

[Anzaniste]

I have bought a new CVA lathe with a taper turning attachment and passed my old lathe on to my nephew.

My new lathe is imperial whereas my old one was metric however that is no problem however the new lathe seems to exude rusty oil all over the slides so I am gradually delving into the problem.  I suspect there is rust water in the lube pump as the suds sump has stood for a long time without action other wise the lathe looks in good fettle for its age.

I stripped down the top slide ‘cos there was 60/70 thou play in the nut and one of the nuts that locks the angle of the slide had stripped. No body seems to stock a ½” x 8tpi acme tap so I decided to bodge. I put a 1/16” slit across the nut about ¼” from the end and then a couple of 4BA grub screws to force the slot apart and bingo it seems to work. I have to get a shorter grub screw before I reassemble the slide but I see no reason why it should not work.


cvanut8 by Anzaniste, on Flickr


cvanut5 by Anzaniste, on Flickr


cvanut2 by Anzaniste, on Flickr

As a precaution I have ordered from the ‘States a bit of ACME threaded bar and a matching nut.

My latest problem is the ball races in the slider for the taper  attachment. Theses ball races are on an eccentric and can be adjusted to take up free play. Lord knows how but  one of the ball races has broken.


CVA4 by Anzaniste, on Flickr

My problem is I’m not sure how to remove the eccentric pin.


CVA3 by Anzaniste, on Flickr

This is the underside view. I have given the pin an exploratory tap with a punch and there was no sign of movement. As the pin rotates reasonably freely I would have expected some movement but there was none. Before I whack it even harder I thought someone out there might have more knowledge and would offer advice. As far as I am aware the Monarch lathe in the states is the same.

Having tried a bit of a tap with a pin punch but detected no sign of any movement I didn't want to  bash away and smash something I thought I would seek advice.
Can any body offer any  suggestions?

[John Stevenson]

I have a CVA as well and as far as I know those pins tap out on the taper turning but in all fairness I have not had to touch mine.

The rusty water could be an oil pump issue on the carriage, see the article on Tony's lathe web site.
www.lathes.co.uk and drop the bottom to clean out.

John S.

[Anzaniste]

Thanks for that reply John, the Tony Griffiths route is where I'm at at the moment.
Another problem that I have is the cross feed clutch doesn't release unless you put a large amount of back pressure  the winding handle having released the clutch lever. I have not yet tried slacking off the adjustment nut on the front of the handle but have this feeling of doom that it is something else. Have you had this problem?

[kvom]

A good source of info and help is the Monarch lathe section of the Practical Machinist website.

[wmclaughlin]

Hi, just discovered this forum while doing a trawl for 'CVA lathe'. I bought one of these a few years ago with the taper turning attachment and had to replace the bearings. If I remember correctly you need to remove the locking rings and screws completely and the adjuster should tap out.

Where did you order the feed screw and nut from?

I have to admit I haven't really used mine too much although I did clean it up and sorted out the saddle lubrication. They are a lovely lathe. All the best with yours.

Willie

[Anzaniste]

A good source of info and help is the Monarch lathe section of the Practical Machinist website.

Thanks for that kvom, I'm posting on there as well.

[Anzaniste]

HELP!!

Oh woe is me! I have been a clumsy chap and I have broken the adjusting gib strip on the top slide on my CVA. The slot is a close fit on the adjusting screw collar and thus locates the gib in both directions. Now it is broken the collar only locates the gib strip in one direction

Photo 1


DSCN0235 by Anzaniste, on Flickr


The strip is 7 ½” long and 5/8” wide it is 5/16” thick at one end and 1/8” thick at the other. I have measured the angle using one of those digital angle gauges and the taper is 1.2 degrees.


DSCN0236 by Anzaniste, on Flickr
Ideally I would like to get a replacement strip. Has any one out there got a spare, would a Monarch  one fit?
Failing that has any body got a complete top slide they could spare.

Currently my approach is to put a strap across the opposite end of the slide and have a 2BA grub screw acting on the other end of the gib strip. My fear is that 2BA is to small and it would look horrible anyway.
   
If some kind soul could get me out of the mire I would be very grateful

[andyf]

1.2 degrees is a shallow slope. Pending a better solution, would the gib still pull up close enough if you lop off the broken end and original slot along the red line on this pic, and then cut a new slot as shown in green?



Andy

[Anzaniste]

Dunno but it is a good idea I'll check tomorrow.
Some one has suggested on another site lopping the end off and pegging and screwing another bit on. Apparently his Bridgeport is still operating happily on said fix. It also occurred to me that a blob of weld in the right place might just fix it . I'm a bit nervous about that approach.
The fracture looks quite brittle suggesting a hardened steel however I've just come in from the shed having given it an exploratory rub with a file and it filed OK.
I'm feeling less  depressed that I was a few hours ago. Thanks for the words of encouragement, its what a chap needs at times like this, that and buckets of tea!

[nearnexus]

You should be able to bronze braize the broken bit back on.

Bronze onto each mating surface separately and then put them together and re-melt into a bond.

Allow to air cool, then reface the surfaces on a linisher.

You could quench it in water to harden it, but that can cause distortion on something like this, so I wouldn't.

Alternatively you could grind the end square and bronze a piece of steel onto the end, then refinish it to size.

I have a Bullfinch (UK made) very high temperature LPG braizing gun and it is excellent for hard bronze braizing up to one inch sized metal.

Well worth the investment for this type of work, plus general bending and small repairs and model making.

Rob

[NickG]

Hi, is that an MG in your avatar and what on earth have you done to the poor thing! 

[Anzaniste]

I say old chap, do have a care in what you say, that car is a Frazer Nash of 1925 vintage. Unfortunately nano seconds after the shutter closed the poor old thing was upside down. In my ownership it has taken part in every known motorsport discipline from mudplugging to racing including driving tests ( see avatar). It has been over the Alps a couple of times and climbed the Stelvio passs. That's what sports cars are for - using hard.


DSCF3659 by Anzaniste, on Flickr

The Stelvio Pass.

[Anzaniste]

Back on subject. I dither around for a while sifting the good  advice I had been given and in the end I decided to go for the build up of braze technique, thanks for the cast iron tip Wayne from the Practical Machinist forum.
My welder pal put a good big blob of braze on for me.


DSCN0238 by Anzaniste, on Flickr

I then on a big ugly grinding wheel removed the large portion of the braze.


DSCN0239 by Anzaniste, on Flickr

I was a bit scared of grinding away the piece I was trying to rescue and I don’t have a linisher so I improvised a grinding fence on my unsophisticated grinding wheel


DSCN0240 by Anzaniste, on Flickr

I fixed the fence, a piece of ¾ square, using a tool maker’s clamp, and a dummy work piece and a piece of 0.015 shim against the side of the wheel to ensure a close pass with out removing metal from the gib itself.


DSCN0241 by Anzaniste, on Flickr

The next stage was to draw file down to the base metal without removing too much. Because I was dead scared of overdoing it so I treated myself to new files. One new thing I learned is that the smaller the file the finer the teeth for as given cut. In other words a Number 3 cut 4” file is a lot finer than a Number 3 cut 8” file. I always thought a Number 3 cut was a number 3 cut.
The 4” file came in very handy for filing the groove to size.


DSCN0242 by Anzaniste, on Flickr

Lo and behold the adjusting screw collar fitted nice and tightly.


DSCN0245 by Anzaniste, on Flickr

Thanks to everyone’s  advice and encouragement  I now have a  top slide that works again. I’m still kicking myself  for having bust it in the first place and losing a couple of days  before I get back into action again. I only started out to clean the lube system, not rebuild the whole lathe!!!!!

[kvom]

I only started out to clean the lube system, not rebuild the whole lathe!!!!!

Famous last words.   

[NickG]

Wow, sorry about that! It's a small pic, that's my excuse! Amazing!

[Anzaniste]

Apology graciously accepted. Here is a larger copy.


Nashwhoops by Anzaniste, on Flickr

And another in less trying circumstances.


DSCF3599 by Anzaniste, on Flickr

[andyf]

Nice matching pair in the last pic, Anzaniste. Two spare wheels, apparently of different diameters. Are the front/rear wheel sizes different?

Andy

[Anzaniste]

Nope. The seemingly larger one is just an extra  tyre strapped to the normal spare wheel. On this trip I was running on beaded edge tyres so two spares seemed like a good idea. As it happened neither was needed.
If you like old cars look here http://www.longstonetyres.co.uk/page/longstoneClassicCars to see other cars in my family.

[rleete]

You are certifiably insane!

[andyf]

Great link, Anzaniste!

My only cars of any note were a Jowett Javelin when I was at University in the '60s, and the 1947 Lea Francis Sports which replaced it (for £110!), but marriage in 1969 soon put a stop to the latter, among other things.
 

Andy

[NickG]

Absolutely brilliant! My dad's got a 1937 MG VA he's slowly, very slowly getting back on the road ... will have to gee him up to get it done now! Doesn't need much doing, only driven it once, probably about 10 years ago and I remember being scared of it, should be able to deal with it now though!

 

anyway, sorry for going  back to the lathe!