I'm trying to repair a loader for a machining cell. A shaft that drives the loader between machines is highly fubared. 25mm shaft that is now 22mm where one of the bearings ride. No wonder we were getting torque alarms.
Anyway, my co-worker welds up the shaft for me. Btw, wrapping things with fiberglass tape that you don't want weld on is fairly handy. He got carried away slightly and welded a few threads that the bearhug nut uses to secure the bearings.
No big deal, 10 mm of threads, 1.5mm pitch. I'll just put the lathe in neutral and turn the chuck by hand since this is an imperial machine and you can't open the half nuts.
Read the charts, put the gears and levers in the right place, pick up the thread and damn, I'm cutting where I shouldn't be.
Back away from that part Wes, something is wrong.
I spent over an hour looking all over this lathe, reading the chart over the QC gearbox and finally I started working though the ranges and measuring pitch. I finally found a combination that cut a 1.5 mm pitch but it isn't what the chart indicated. This is on a Servoshift Leblond. I had the right change gear combination installed.
The moral of the story, if you are going thread something that really needs to not be screwed up, either know your lathe or make a test pass on scrap to check your setup or do both.
> Read the charts, put the gears and levers in the right place, pick up the thread and damn, > I'm cutting where I shouldn't be.
> Back away from that part Wes, something is wrong.
> The moral of the story, if you are going thread something that really needs to not be > screwed up, either know your lathe or make a test pass on scrap to check your setup or do > both.
> Wes
Wes, If I'm picking up a thread like that I make a test pass above the major dia. first to see if things look right.
On Sat, 07 Nov 2009 18:45:26 -0500, the infamous Wes <clu...@lycos.com> scrawled the following:
>I'm trying to repair a loader for a machining cell.
Izzat anyting like a terrorist cell?
<hiding>
-- The Smart Person learns from his mistakes. The Wise Person learns from the mistakes of others. And then there are all the rest of us... -----------------------------------------------------
On Sat, 07 Nov 2009 18:45:26 -0500, Wes <clu...@lycos.com> wrote: >I'm trying to repair a loader for a machining cell. A shaft that drives the loader between >machines is highly fubared. 25mm shaft that is now 22mm where one of the bearings ride. >No wonder we were getting torque alarms.
>Anyway, my co-worker welds up the shaft for me. Btw, wrapping things with fiberglass tape >that you don't want weld on is fairly handy. He got carried away slightly and welded a >few threads that the bearhug nut uses to secure the bearings.
>No big deal, 10 mm of threads, 1.5mm pitch. I'll just put the lathe in neutral and turn >the chuck by hand since this is an imperial machine and you can't open the half nuts.
>Read the charts, put the gears and levers in the right place, pick up the thread and damn, >I'm cutting where I shouldn't be.
>Back away from that part Wes, something is wrong.
>I spent over an hour looking all over this lathe, reading the chart over the QC gearbox >and finally I started working though the ranges and measuring pitch. I finally found a >combination that cut a 1.5 mm pitch but it isn't what the chart indicated. This is on a >Servoshift Leblond. I had the right change gear combination installed.
>The moral of the story, if you are going thread something that really needs to not be >screwed up, either know your lathe or make a test pass on scrap to check your setup or do >both.
>Wes
Or do a ghost pass where the bit won't touch the metal but you can see where it might.
On Sat, 07 Nov 2009 18:45:26 -0500, Wes wrote: > I'm trying to repair a loader for a machining cell. A shaft that drives > the loader between machines is highly fubared. 25mm shaft that is now > 22mm where one of the bearings ride. No wonder we were getting torque > alarms.
> Anyway, my co-worker welds up the shaft for me. Btw, wrapping things > with fiberglass tape that you don't want weld on is fairly handy. He > got carried away slightly and welded a few threads that the bearhug nut > uses to secure the bearings.
> No big deal, 10 mm of threads, 1.5mm pitch. I'll just put the lathe in > neutral and turn the chuck by hand since this is an imperial machine and > you can't open the half nuts.
> Read the charts, put the gears and levers in the right place, pick up > the thread and damn, I'm cutting where I shouldn't be.
> Back away from that part Wes, something is wrong.
> I spent over an hour looking all over this lathe, reading the chart over > the QC gearbox and finally I started working though the ranges and > measuring pitch. I finally found a combination that cut a 1.5 mm pitch > but it isn't what the chart indicated. This is on a Servoshift Leblond. > I had the right change gear combination installed.
> The moral of the story, if you are going thread something that really > needs to not be screwed up, either know your lathe or make a test pass > on scrap to check your setup or do both.
> Wes
If there's some thread there already do "air threading" -- line the point of the tool up with the valley (or point) of the thread you're cleaning up and let 'er rip (or crank the thing by hand, as appropriate).
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