C0630

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Mughalsamrat
Posts: 4
Joined: Wed May 16, 2018 12:17 am

C0630

Post by Mughalsamrat »

hi guys i am new here and got an old latheis model is c0630 Y lathe the problem is its cutting the thread .... always go off the track while threading guide me what could b the reason and from where i can get its manual as its very old model and can any one plz show me how to install its disc for " threading as there is only Chinese written there unable to understand
thankx

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choprboy
Posts: 322
Joined: Sat Oct 29, 2011 11:23 pm

Re: C0630

Post by choprboy »

No direct information, but have a look at this previous thread and use a web translator on some of the linked Chinese pages:
http://www.chaski.org/homemachinist/vie ... p?t=102256

In particular I notice that one of the pictures shows what appears to possibly be a small 30-ish tooth gear on the spindle-drive gearbox output, a 127 tooth idler gear, and a 120 tooth on the quick-change gearbox input. That odd gear ratio may cause the threading dial to not indicate with the spindle correctly.

The lathe could also have a metric lead screw (since is seems to be a Chinese primary market lathe) to ease metric threading operations, which would cause a mis-match when performing English threads. When using an English lead screw to make metric threads (or vice versa a metric lead screw to make English threads), you must leave the threading lock engaged and reverse the lathe out of the cut every time. You can not disengage the lock and have the spindle aligned with the threading dial the next go round.
John Hasler
Posts: 1852
Joined: Tue Dec 06, 2016 4:05 pm
Location: Elmwood, Wisconsin

Re: C0630

Post by John Hasler »

choprboy writes:
The lathe could also have a metric lead screw (since is seems to be a Chinese primary market lathe)
to ease metric threading operations, which would cause a mis-match when performing English threads.
When using an English lead screw to make metric threads (or vice versa a metric lead screw to make
English threads), you must leave the threading lock engaged and reverse the lathe out of the cut every time.
You can not disengage the lock and have the spindle aligned with the threading dial the next go round.

In that case why would it have a threading dial?
choprboy
Posts: 322
Joined: Sat Oct 29, 2011 11:23 pm

Re: C0630

Post by choprboy »

I don't understand your question... lathes have threading dials to ensure you re-engage the threading lock on the same position of the lead screw relative to the rotation of the spindle, which varies based on the lead screw/gearing of a particular lathe setup. When cutting a thread that is a fractional ratio of the lead screw/gearing setup, you need to use the threading dial (or more specifically, particular indicating marks on the threading dial). Metric lead screw lathes have threading dials for this purpose too. See half way down:
http://www.model-engineer.co.uk/forums/ ... ?th=107351
As well as:
http://www.fwhercus.com.au/jrdebay/ebay ... _Chart.jpg
https://images.machineryhouse.com.au/pr ... g-Dial.jpg
http://www.practicalmachinist.com/vb/at ... l9-10a.jpg

When cutting metric threads on an English lead screw, or English threads on a metric lead screw, you are further limited by the conversion of 25.4mm to 1in, (127/120 gearing), which negates the original gearing ratios the threading dial was based on. So the threading dial indicators can not be used at all when cross-dimension-system threading.
John Hasler
Posts: 1852
Joined: Tue Dec 06, 2016 4:05 pm
Location: Elmwood, Wisconsin

Re: C0630

Post by John Hasler »

Guessing from the OP's name I think he has a metric lathe and is working in metric.
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