Thinking of building a gearbox
|Andy Carruthers||14/03/2019 07:12:53|
221 forum posts
I have a WM180 and dislike gear changing for cutting threads, there has to be a better way - and yes, this might be academic as I intend to purchase a bigger more comprehensively equipped lathe this year
On the WM180 within the gear train cover space is very limited, as an aside, moving the motor would help. Having looked on YouTube, some of the home-built gearboxes are substantial both in size and weight, which got me thinking
I know the WM180 uses Module 1 gears for the chuck drive, I wonder if I could gang a 40T Module 1 gear with a 40T Module 0.5 or 0.75 gear to reduce the physical gear size then reflect the new Module down the gear chain to the lead screw - I cannot see any great load issues but I might be missing something blindingly obvious, it has been known...
|Robert Atkinson 2||14/03/2019 07:26:38|
205 forum posts
The obvious answer to me is to ditch the gearbox and direct drive the leadscrew with a servo motor (or stepper) with a controller that is driven by pulses picked up from the headstock spindle (reluctance sensor off existing gear teeth or a new opto.). Any decent controller will be able to electronically gear the servo to the head at whatever ratio you need.
Then again I'm an electronics engineer.
|Andy Carruthers||14/03/2019 07:32:14|
221 forum posts
Now that is a very appealing option, thanks Robert, blindingly obvious now you have mentioned it
Time to get my thinking cap on
|Michael Gilligan||14/03/2019 07:36:49|
12931 forum posts
I know next-to-nothing about the WM180, but the basic principle of what you propose is quite reasonable.
Martin Cleeve did this:
|Andy Carruthers||14/03/2019 08:15:34|
221 forum posts
Thanks Michael, I appreciate the confirmation
Martin Cleeve is indeed a very clever man!
I do have to seriously think about my approach, Robert's suggestion has the appeal of space saving, less machining and is non-machine specific in it's implementation, worthy of an article when I get my act together
|396 forum posts|
In answer to the original question, yes you can mix the module or dp, but obviously in pairs. One thing to bear in mind though that gear power and wear are proportional to the module and number of teeth. So if you had a gear in the train of 18T at 1 mod it would need to be 36T at 0.5 mod, unless you use a stronger material. Using different tooth sizes will enable you to get odd ratios probably in smaller sizes, I.e using 127T at 0.5mod.
|John Pace||14/03/2019 08:38:32|
|126 forum posts|
Myford .8 module change wheel set and Warco Gh 1000 1 module change wheels ,both keep within the machine covers.
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