Thread dial indicator.

Suzuki4evr

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Hey chippers
Is there something on this site about making your own thread dial indicator for metric and imperial threading. I can't seem to find any,maybe looking in the wrong place. I have a metric Mashstroy lathe with the thread dial indicator missing. I've been threading without it for very long time now, but it is taking to long when doing long threads. Any help would be appreciated.

Michael
 
You don't need a thread dial. When you cut threads, pull the tool out at the end of the thread, reverse the motor without disconnecting the split nut, at the beginning of the thread, reverse the motor again and cut another pass. It may sound like a pain, but it's faster than you think when you don't have a dial
 
I made a new thread dial for my Grizzly lathe but not the axle and gear. The first step is to determine the lead of the lead screw on inches/ thread if Imperial or mm/thread if metric. Most Imperial lead screws are either 8 tpi (.125" lead) or 16 tpi (.0625" lead). Your mating gear has to have the same pitch to mesh with the lead screw. Some gears are cut with helical teeth to match the helix of the lead screw but another common technique is to rotate the axis slightly to mesh so an ordinary spur gear can be used. There is no load involved so you can get away with a less than perfect mesh.

Normally, the gear would have four times as many teeth as as are in one inch of the lead screw for and Imperial setup. This means that the thread dial makes on complete revolution for four inches of carriage travel. The dial then has four numbered marks and four in-between marks. My Grizzly is an exception as the lead screw has 12 threads/inch and 36 teeth on the gear, making a complete revolution in three inches. It has 12 markes on the dial. Metric lead screws & thread dials work in a similar fashion.

The difficult part would be finding/making the gear. A little searching, once you know the diametral pitch, should turn up a suitable gear. An axle and housing would have to be made as well as a thread dial. It is possible that you might be able to find an assembly from another lathe that could be modified to fit yours.

edit: re-reading your post, I see that the lathe is metric. The procedure is the same though. SPI has low cost metric gears which will work for you. http://www.sdp-si.com/products/Gears/Index.php
 
You don't need a thread dial. When you cut threads, pull the tool out at the end of the thread, reverse the motor without disconnecting the split nut, at the beginning of the thread, reverse the motor again and cut another pass. It may sound like a pain, but it's faster than you think when you don't have a dial
Thank you,but I know this and this is how I've been doing it,but like I said,when I do long threads it takes to long for my taste, but thanks for the input
 
I dont think it would be too difficult to knock up a brass gear for your leadscrew. As has been pointed out it doesnt have to be exact. Im sure a flycutter could do it.
 
Hi Guys,

I've rescued loads of gears, most of them plastic, from old printers, photocopiers etc. Its possible you might get a suitable gear that way.
 
Thank you,but I know this and this is how I've been doing it,but like I said,when I do long threads it takes to long for my taste, but thanks for the input
If speed is your #1 CONCERN then buy a NC lathe, input the start Z and the end Z, start diameter and finish diameter and the lead, this can be either metric or inch, it does not matter as lead is lead regardless of units.
 
I have thought about doing this as well and wondered what was involved. Great info RJSakowski. I don’t see an NC lathe as a solution. Sorry but its not what he’s wanting or asking.
 
Me too. I’ve got buckets full of printer gears! I am amazed at the quality and design of some of them, especially the brass worm gears. One day I’ll make up a powerfeed or something cool with some of these gears.
Hi Guys,

I've rescued loads of gears, most of them plastic, from old printers, photocopiers etc. Its possible you might get a suitable gear that way.
 
Michael I once asked the very same question that you asked . I recieved a pm and a guy in JHB who is very talented had the same lathe as me EMCO v13. He built me one for free .But looking at it ,theres not much to it.
Do you have a manual for this lathe because it may take the guesswork out of the size and teeth on the gear.
Heres mine. He didnt have no stamps so just colour coded the dial.
 
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