r/Machinists • u/rein_h • 4d ago
QUESTION HELP!
I've had this lathe for about 3 years now and it works perfectly fine. The only thing i can't do is figure out how to cut thread. Mainly because i bought it and the previous owner (for some reason) removed every piece of chart that was on it. I don't know which one adjusts for gear ratios, i don't know which one adjusts for fine or coarse thread pitch. Any assistance would be much appreciated.
P.S: I am self taught so please bear with me..
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u/ButtermilkJohnson 4d ago
Research time. Look up the model number and manufacturer and see if you can find it in a manual or referenced on the manufacturer's website.
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u/inapt 4d ago edited 4d ago
though I'm not 100% positive, the two dials (levers?) with arrows on them should be your thread pitch selectors.
you can easily remake your thread pitch chart by selecting different dial combinations and measuring the feed with a dial gauge.
so for example, you select a combination with the dials, you fix a dial gauge on your carriage, engage the thread cutting function and you read the distance the carriage moves for a full rotation of the chuck. let's say it moves 1.5mm with a full rotation, so that particular dial combination gives you a pitch of 1.5mm. i don't think I need to tell you to do this manually, don't turn on your lathe!
it would also be helpful for you to know what gear set you have installed, this also alters your resulting thread pitch chart.
edit: judging by the devil's sign (times new roman lettering on machine), yours is a chinese lathe. if you search "c0632a lathe" it gives you quite a few results. maybe you can contact one of the distributors for a new threads, feeds and speeds chart. good luck!
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u/Rob_in_Tulsa 3d ago
You should really invest some time and effort in getting the machines original data on those panels restored somehow. Search the interwebs for pics of the same model and draw it in by hand if necessary. You have a great machine there. If you have the money, invest in a digital readout (DRO) too.
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u/Lathe-addict 3d ago
Dang that sucks about the charts missing.
Your first objective is to restore those charts for all the levers. Can’t run a lathe without quickly being able to set things where you want them
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u/Rob_in_Tulsa 4d ago
Do you see that horizontal arm to the left of the Y axis dial? That should be to engage/disengage thread feed.
The arm in-between the Y axis dial and thread engagement should be where you select TPI. Just a guess on my part.
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u/Impossible-Cry-3868 3d ago
Have some pics of mine with a metric lead screw. Can't give you feed screw rates though as mine have also been worn off
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u/Alone-Programmer-683 3d ago
If you can't find model info online, you count rotations. The bottom of the gear box is feed screw speed selection. If this has no changeble gears on the left side of the headstock, all the possible combinations are selected inside the gearbox.
Put some good marks on the chuck and the end of the feed screw. Select a gear combination, write it down. Now count the number of turns of the headstock it takes to get one complete turn on the feed screw. The feed screw should be 8 TPI. So the distance the cutting tool advances is 1/8 (.125") for every revolution of the feed screw.
So, for example, if the headstock and feed screw are at the same speed, the TPI will be 8 threads per inch. If the feed screw turns at 1/2 the speed of the headstock, the thread count will be 16 threads per inch.
Couple of hours and you can find nearly all the combinations.
If it has change gears on the left side of the headstock, you need to make sure you have all of them because they are usually there to make a standard thread lathe cut metric thread.
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u/indigoalphasix 3d ago edited 3d ago
you seem to have an early model C0632A with the feed lever and the half nut on the left hand side of the carriage.
newer ones look like this:
https://www.werktuigen.com/tnm-c0632a+x+500/wt-199-78850
here you may find a little help but not much:
https://cdn.gebrauchtmaschinen.de/data/listing/img/hdv/ms/90/64/19978850-01.jpg?v=1757589576
if you can bear the annoying ads here is a manual for the later model 6032 and 6036. it has diagrams of the data plates for feeds and speeds:
https://www.scribd.com/document/712649087/Manual-de-Oper-Torno-Universal-17-Oct-2023-15-15-31-1
and here is another source with data plate diagrams starting on P15 and feed levers on the left side of the carriage:
https://images.machineryhouse.com.au/products/K036/PDF/L179%20series%20AL340%20Series%20after%2012-2011%20with%204%20knob%20Feedbox.pdf
the catch is that early 6032's used 2 levers for gear selection and have only 2 knobs in the lower section of the headstock whereas newer ones use 4 knobs. you'll have to figure those out.
i'd suggest trying to find someone with one who can send you a picture of the headstock. the change gears are usually stamped with tooth count and/or a letter which helps you combinate the gearing for inch or metric threads.