# 3D printed change gears



## Weldingrod1 (Dec 10, 2013)

This weekend I needed to cut an 8 pitch thread on my "new" Hardinge TL-10.  A check of the quick change chart led to a sinking feeling; the coarsest pitch was _11_!  I opened up the change gear cover and found that not only did I not have the change gears, I didn't have the bracket to put them on!
After some cussing and a LOT of thinking, I realized that my 3D printer was the answer!  I carefully measured the change gear shafts and spacing, and figured out what the ratio was from the spindle to the first shaft (0.8 reduction in mode 1, in case you need to know).  I laid out a pair of gears with the correct center to center dimensions, the largest possible face width, and tooth ratio, then printed them.  After the first mistake of diameter vs radius (oops), the second set fit perfectly!  I cut the 8 pitch thread last night!  This set of gears will also allow me to cut 16 and 32 pitch threads using the three position mode lever.  One irritation of this method is having to remove the collet draw bar, as you can see in the picture.


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## Bill Gruby (Dec 10, 2013)

I like the idea but wonder how they will stand the test of time. Great idea though. I like thinking out of the box. Kudos to you.

 "Billy G"


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## xalky (Dec 10, 2013)

Nice job! Cool.) What kind of 3d printer are you using?


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## Cheeseking (Dec 10, 2013)

Long enough to get the job at hand done I suspect.   Hard to say from the pic but my guess is FDM process using ABS.


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## DAN_IN_MN (Dec 10, 2013)

Nice work!  Pics of the printer please!  I want to build one!


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## Weldingrod1 (Dec 11, 2013)

The gears are ABS plastic, three shells, 30% solid.
I didn't see any issues during my threading but yes, there is a potential tooth wear issue down the road.  However, I can always print another set!  I have a printed reduction gear set on my printer.  I'm on my fourth pinion gear, but the original bull gear.  One issue with small pitch gears is that the tooth dimensions get near the filament width.  Coarse is the way to go on printed gears!

My printer is an Emaker Huxley; visit RepRapPro.com for the current version.  Its currently in a ventilated, temperature controlled box, but I don't have a recent picture on my computer.  It will build parts up to 140mm square and about 90-95 mm high (there is a missing strip on the upper left due to interference between the extruder head and the frame).


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## roygpa (Dec 11, 2013)

Nice printer, I've built 2 Reprap Prusa printers and printed parts for a third, and also built a Lulzbot Taz.

I've been having a lot of fun with it over the past couple of years.

Roy


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## Kevin45 (Dec 20, 2013)

Nice job!!! 

Just out of curiosity, how long did it take to print off both gears? It's going to be a while before I make a leap to a 3D printer, but I am very interested in one. Are you willing to disclose how much yours cost for the curious? If not, totally understandable.


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## Weldingrod1 (Jan 6, 2014)

Sorry for the slow replies!
The gear set took at least 12 hours to print.
I bought one of the first printer kits made in any quantity: the Emaker Huxley for $550.
http://www.indiegogo.com/projects/emaker-huxley-3d-printer-kits 
He sold out of the first hundred in a day, and said "I guess I could make a few more..."  300 printers later he had significantly increased the number of 3d printers on the planet!
His success led to an explosion of 3d printer kits.

Regards,
Rod


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