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Cva mk1 help!

ir9074

Aluminum
Joined
Feb 3, 2018
Hi all. I have a 1949 cva mk1. It's a direct copy of a round dial 10ee, except for the motor and drive arrangement. The lathe was bought part restored and is not nearly complete, but running it showed that in screwcutting drive the headstock clunked.

Further investigation has shown the revrrse idler is missing teeth.
Does anyone have one or have any ideas what to do?

My guessing is the original will be hardened and profile ground.
I could maybe make one, but it'd never be as good as an original.
This lathe is otherwise perfect and complete.
Thanks.
Ian
 
If the round dial is like the square dial (likely) the gears are not hardened. The left gear is a 18 pitch and the right gear is a 16 pitch if I remember correctly. The smaller tooth size is because the idler gear is in the gear train and the gear has to be physically smaller. The idler for the left gear would be 18 DP if I am correct. I assume 20 degree helical, that could be determined by the OD.

In any event, Monarch may have a used one at a reasonable price, if not I can make you one for almost as reasonable price.
 
Thank you for your fast and helpful reply. I have emailed monarch. My gears look as you describe. Am I to assume 14.5 degree pressure angle? Are you uk based? Thanks for the offer to make one. Would it be hobbed ot single tooth cut on a universal? I can do the latter.
Ian
 
Wow! This would be amazing. I will be stripping the headstock in the not too distant future to remove the gear. The headstock only contains five gears in total. On the spindle nose side (right) the forward gear snd its partner on the driven shaft. On the left,the reverse gear and its idler (beneath and barely visible)plus the partner on the driven shsft. I'll take a few photos inside the headstock, but it'll be a little while before I strip it out. THANK YOU,
Ian
 
They are 14.5 PA. I have a hobber, but if you have a knee mill, and a universal indexer, and the gears to set up for the proper lead, and a #2 cutter for the DP, you could make it yourself. I have a program that gives 4 gear ratios to 6 decimal places so I can help you with the proper gears.

Anyway, if Thermite has the gears you are good. As I tell potential gear customers, the cheapest way to make a gear is to buy it. Gears are an expensive hobby. Good luck
 
Again, thank you. I'll remove the gear and hope Thermite has it. I have a B&S universal light with its original accessories, including the gears. I think I can calculate which gears I need, but will ask for help if neccessary. How do you know it'll be a no 2 cutter ? Do you know the number of teeth the gear has? I thought they woild be 14.5pa on a 1949 machine, so nife to have it confirmed. How do I put photos on here?
Ian
 
For Dp cutters the cutter number goes inversely with teeth number. Module cutters make more sense, cutter 1 is few teeth, cutter 8 is infinite teeth. I made a mistake, I was thinking of the gears on the reverse shaft, which I think are 60 tooth. You mentioned the idler, so it probably will be cutter 3 or 4.

This is from the KBC catalogue, but cutter numbers are listed in many sources.
 

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Bll230. Thank you for the information. I was aware of the involute cutter designations, but unsure of how you knew the tooth jumber!
Thermite. I've emailed you what I know! It is indeed the part you refer to.
Many thanks to all for your help so far!
Ian
 
Cal. Thank you for that information. I now have two cvs contacts in the uk and possibly a third thanks to you.
Thermite. Although I think I can make a suitable helical, I know it'll never be as good as the original. The tooth form will be an approximation, the finishing probably inferior and the material possibly not right. Additionally, I'd have to work out the spec details and spend a great deal of time. The whole thing would be interesting, but I'd rather buy the real deal! Repairing is a similar deal.
I've made plenty of gears and have the kit, but this lathe is otherwise right and I'd like to complete the job properly.
If, btw, I don't reply to a direct email, it's because cyberspace randomly eats inbox arrivals, so I'd need to give you a different address.
One day I'll figure out how to post a photo!

Ian
 
I have indeed a manual for parts.

Somewhere, but not obvious at the moment, I have details of the tooth pitches of the headstock gears.

All I can see at the moment is that the larger gears are all 56T.

If you need a scan of any of the parts or operators manuals I can do this.

Regards.
 
Well, I eventually found a guy in the UK who has loads of cva lathes, some for spares. He has all sorts of stuff. Anyhow, I've now bought everything I need from him at a good price. For future information, the round dial 10ee and all versions of the cva have the same headstock and banjo gears. The later cva reverse idler sits on a shaft that is retained by a grubscrew under the headstock. My early cva has exactly the same arrangement, but the shaft is a light press fit and has no grubscrew. I assume the 10ee is the same.
Thanks to everyone for their help.
Ian
 








 
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