lathe crash

[PatMiles]

Pat,If I were you,I'd make a new shear pin out of brass,if nothing else. Those shear pins are SUPPOSED to be made of VERY soft steel,like old fashioned rivets are made of. Apparently your Jet did not have a shear pin made of the proper material.

I know of an instance,in the machine shop of a local college,where someone sheared off the pin,and made a replacement pin from STAINLESS STEEL. The next time a student crashed that lathe,it tore the face of the quick change gearbox off. It was a 9" South Bend lathe.

Correct metal in the shear pin is VERY important.

George,
The pins are brass.

 

[NightWing]

My G0602 jammed in the cut which stopped everything except the motor, which was still trying to drive the slipping belt. The cut wasn't excessive, the spindle speed wasn't excessive and the material was mild steel. I have had this happen several times. That wimpy belt is a piece of crap and (in my opinion) too narrow for the job. I have to adjust the idler so tight that I am concerned that the bearings will fail.

 

[Shadowdog500]

Thanks for the tip on soft shear pins. My Taiwanese lathe has roll pins. I may turn some pins out of brass this week.

chris

 

[GarageGuy]

My G0602 jammed in the cut which stopped everything except the motor, which was still trying to drive the slipping belt. The cut wasn't excessive, the spindle speed wasn't excessive and the material was mild steel. I have had this happen several times. That wimpy belt is a piece of crap and (in my opinion) too narrow for the job. I have to adjust the idler so tight that I am concerned that the bearings will fail.

When you are learning, a belt that slips is a good safety valve. My first lathe had a flat belt that could slip, and although I only crashed it once, nothing bad happened because the belt slipped.

GG

 

[GarageGuy]

I hate to say it, but I did this twice

Especially while learning, be sure to slow down your spindle and feed speeds. Also eliminate anything that could distract you. I silence my phone when working with machines so I'm not tempted to look away, even for a second. Just a couple of observations from my own learning process.

GG

 

[spaceman_spiff]

My strategy at dealing with this sort of thing is to learn to accept that you will break stuff learning to machine..end mills, tools, machinery, workpieces..its going to happen. If you never break anything while learning then you are not learning aggressively enough and are playing it too safe to really push your skill acquisition and confidence. Thats why its good to learn on cheap machinery that you can afford to hurt and repair. I've known machinists with years of experience but not very well developed skills and a low confidence level, and they were always the most timid about trying new things, and, ironically, the ones who seemed to always be hurting themselves.

I'm not saying to be reckless or just wing everything and cross your fingers, but at the same time, you should be willing to go into "the unknown" and experiment. As others have suggested, putting in "safety valves" like slipping belts or other things can be a great way to allow you to be aggressive about learning but reduce the casualty count of your poor equipment. I think thats the path to follow.

 

[NightWing]

When you are learning, a belt that slips is a good safety valve. My first lathe had a flat belt that could slip, and although I only crashed it once, nothing bad happened because the belt slipped.

GG

I'm not a learner. I have been running lathes since the 60's I have been in metalworking since then and owned a machine shop for 22 years. The belt drive on the G0602 is trash.

 

[GarageGuy]

I'm not a learner. I have been running lathes since the 60's I have been in metalworking since then and owned a machine shop for 22 years. The belt drive on the G0602 is trash.

I apologize. I didn't mean to imply that you were. There are lots of people here who are, though. Myself included.

GG

 

[NightWing]

I'm cool.:allgood: