Lathe as dividing head using threadcounter

mercredi 18 novembre 2015

Hey,

Am aware of various discussions regarding using the lathe headstock as a dividing tool, such as directly on the bullgear, off a spur gear mounted on the mandrel and also off the spur gears in situ - have seen people do compound indexing like a Sparey divider using the spur gears in situ to turn the chuck.

How about this one ? Assuming 8tpi leadscrew and 32 tooth threadcounting gear.

We have an 8tpi wormscrew that drives the carriage back and forth.

We have a "threadcounting dial" (dont know the right name) that is driven by the leadscrew.

So .................... couldnt I simply mount a range of diy dividing plates onto the threadcounter ? There would be some sort of relationship between the distance between the holes on the plates and the amount that the chuck turns.

Does this give me some sort fairly clumsy dividing head with a ratio of 32 ? Doesnt seem quite right - think Ive got it going backwards - will go to shed and have a look.

.............. and while we are talking about the threadcounter thingy ............. am aware of an awful lot of "you can - you must not" comments regarding disengaging the half nuts when cutting metric threads using a 1.27 ratio somewhere in the spur gears. Am aware of making various chalk marks and lining them up when attempting to re-engage half nuts

What if you made up a little gearbox to hang off the 32tpi gear and had the ratio so that it converted imperial to metric and indicated when to re-engage when cutting a metric thread ? Would that then allow one to disengage and re-engage the half nuts with relative ease whilst cutting a metric thread or would you still be snookered because the 8tpi leadscrew and the 32 tooth gear wont necessarily line up correctly - cant quite visualise it in my head.

This was all prompted by a tiny one paragraph article I read a while ago either on another forum or in an old magazine where a bloke said that he could quite easily create a 125 division plate on his lathe just using the 8tpi leadscrew and threadcountingdial (anybody speak German ? would that qualify as one of those gigantic long words that they are allowed to create ?)

Oh yes and again whilst I'm here -I cant quite understand exactly how this 125 dial was to be achieved - Something to do with 1/8=0.125 - Am off to the shed to have a look.

Bill


Read the full thread at metalworkforums.com...


Lathe as dividing head using threadcounter

0 commentaires:

Enregistrer un commentaire

 

Lorem

Ipsum

Dolor