Building A New Change Gear Quadrant For My 12x36 W Qcgb

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master53yoda

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Well i finally decided to bite the bullet and make a new quadrant for the change gears on my QCGB so that I can do metric threads. my patch job had worked ok untill i tried to cut the 8 TPI on the 1.5 spindle thread on my ER40 collet chuck that I'm working on. it dropped out the gear on the last cut about half way through and destroyed the thread.

I'm going to make it out of some 1/2" flat plate, i've cut it out with the torch and once i get it cleaned up Ill post some pics on the mill when i start that part of it. I have been watching EBAY for 9 months and haven't ever seen one come up, they normally are tied to the QCGB when they get put on EBay.

Art B.
 
I'd like to see photos of both projects, even if they are only in-process. The collet chuck is on my short list of projects if I ever finish refurbishing the neglected wood windows on my house.
-Ryan
 
here is the roughed out quadrant Ive just started to clean up the torched areas, I'm not getting a lot of time to work on the lathe as my casting ingot business is getting out of hand, I poured 170 lbs of aluminum ingots today. I'm also working an a pattern set for making jet boat pump intake ports.

Roadie thanks I'll watch it but they seem to go in the 350 to 500 range.



20150316_095059[1].jpg
 
I figured since it says for parts it might not go very high.
What happened to that quadrant?
Looks like someone thru it against a wall and shattered it.
 
when I bought the lathe the prior owner said that the threading gear box didn't work right, when I tore it down the quadrant came apart in pieces. what I found in the end was a BB imbedded in the 13 threads per inch gear in the threads per inch section of the gear box. it would work unless you tried to use that particular thread and it would then jam so tight that it wouldn't turn, the quadrant was the weakest point and it broke and released the in-out gear. It would have been running in the back gears when threading that thread which pushed the delivered torque way up..

I plan on casting a new one in the end but don't have my foundry set up yet for cast iron. I have other things that i want to spend my tooling money on and have a hard time paying over $100.00 for a part. that i can make.

Art B.
 
Just mentioned calling Atlas as you had mentioned you had been watching eBay. A lot of folks don't realize that they still support these lathes after all the years. A lot of the time there price is cheaper for a new item than you can get used for on eBay. Even Sears marks the price up considerably on the items, in the case of half nuts they double the price. Atlas sells half nuts new for $35 and a lot of the time they go for double that on eBay.
 
Some of the ones on eBay are made of brass, too. Which are easier to damage than the original Zamak ones.
 
roadie33 said:
I figured since it says for parts it might not go very high.
What happened to that quadrant
Looks like someone thru it against a wall and shattered it.
Click to expand...

I got the Gear box on Ebay Thanks for letting me know about it, my search that I had setup in ebay didn't pick it up so I wouldn't have caught it myself. I got the whole thing for little over 250 shipped, I can get that back out of the gear box itself.

I think that I'll go ahead and machine the one I'm working on and put it in my Ebay sale stuff somewhere sometime somebody will break one it will be worth 75 to them.
 
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