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Old 04-30-2011, 05:27 PM   #1
Norman
 
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Default reverse tumbler gears for G0602

If you guys are interested in this and with the moderator's permission I can post a link to where I have the photos and my design for adding the reverse tumbler gears to the G0602 lathe. The reverse tumbler is built from 1/4" cold rolled steel plate and a couple of timing gears from a small engine. I think it was easy to build and will come in very handy and a useful modification to this lathe.
this is the reversing gears with shifting lever the small gears are out of a small engine

reversing gears installed on the lathe

Brass knob for forward, neutral, reverse. makes the G0602 a lot more fun

norman

I've also built a speed reducer for the G0602 lathe. My first try at this will slow the spindle speed down to 58 rpms, I'm working on a newer design to make the slower speeds adjustable by changing the input pulley on the speed reducer.
This speed reducer is built from sand castings and again small engine timing gears. You do not have to use casting to build this,I did because it was a less expensive way for me to make the frame for the speed reducer gear box.
Here's a couple of videos of the reducer and the spindle. Kind of boring, but you can see for yourself.



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Old 06-23-2011, 10:09 PM   #2
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Default Re: reverse tumbler gears for G0602

I'm wondering if any of you guys with the G0602 lathe has done the reverse tumbler gears? The plans are free on "Projects in Metal" forum.
I also working on making a easier to make speed reducer, using cast parts and timing gears again. You could use steel strap instead of castings. Instead of using 5 hp briggs gears I'm using timing gears out of a 3 hp briggs, the cam gear is plastic with plastic lobes so machining the lobes off is a breeze.
To get more room between the input and out shafts which the gears are out of a 3 hp engine, I'm using a 5hp crank gear in between the 3 hp gears.



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Old 06-24-2011, 12:06 AM   #3
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Default Re: reverse tumbler gears for G0602



Norman, I plan on making both mods at a future date. Just too many irons in the fire right now.


I want to thank you for taking the time and effort to prove these mods for us.


Ron
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Old 06-24-2011, 12:44 PM   #4
BillTodd
 
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Default Re: reverse tumbler gears for G0602

Excellent work

Have you considered fitting it with a Hardinge style dog-clutch for threading?

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hlv gear train.gif  
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Old 06-24-2011, 03:40 PM   #5
Norman
 
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Default Re: reverse tumbler gears for G0602

Bill
No I haven't I'd never heard of one.

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Old 06-24-2011, 06:20 PM   #6
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Default Re: reverse tumbler gears for G0602

The Hardinge gear train above looks complicated but is essentially very simple:

The spindle drives two gears at a 1:1 ratio one drives a dog-gear forwards, the other drives a shaft to a reversing pair to drive a dog-gear backwards.

Between the two dog-gears is a sliding dog-clutch which drives additional shafts and gears that in turn drive the lead screw. A lever on the front of the lathe moves the dog-clutch into engagement either forwards or backwards, thus the lead screw is driven forwards or backwards.

Critically, because the clutch is in a 1:1 ratio with the spindle and can only engage in one rotational position, the lead screw is always 'in sync' with the spindle .

So, when threading on a Hardinge, the half nuts are left engaged at all times, after a forward cut the tool is retracted with a quick action mechanism on the top-slide and the carriage is reversed using the threading lever. Another forward cut only requires re-positioning of the quick action top-slide lever, plus a little in feed, then the threading lever is pushed forward again to move the carriage in perfect sync. It doesn't matter what thread is being cut imperial metric or DP, because the half-nuts are engaged there's no need for a threading dial.

On the HLV-H there's a threading stop that runs along the apron that can be set to disengage the clutch in a precise manner (<0.001" typically so threading to a shoulder at up to 1000 rpm is perfectly possible).

The whole thing works so well I'm surprised more lathes aren't fitted with similar mechanism. I'm sure if you can retro-fit a tumbler reverse that you could engineer a dog-clutch. (Like this one fitted to a mini lathe : http://www.gadgetbuilder.com/Dog_Clutch.html)

Bill



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