Reply To: machining problem

[Martin Botting 2Participant @martinbotting2]

Hi there fellow swarf makers!

got a small problem I would like to fire into the ether of the www… I am working on a project that i asked for help with ref: understanding German drawings. I am working on the actuating shaft and I have come upon a few glitches. I have attached a screen shot of the part I am trying to machine for your perusal. Now the problem thus far is this, I decided to turn it between centers ( right or wrong) thats what I did Mk1 was all going swimingly UNTIL i was machining the lower end of the component which was now closest to the headstock and the tool ( tipped indexable type) dug in and PING snapped it and I now had a loverly nearly finished part. As you can imagine the air was blue! Nahil desperandum as my old latin teacher would say prior to beating the C@&p out of me… I cleaned the lathe of all the shards of stabby brass and un- screwed the catch plate and re- chucked the collet holder, a fresh bit of brass was duly faced center drilled and then re swung between centers… (Don't you wish you had a second lathe?) and work started again lesson learnt light cuts working as close to the headstock each time to facilitate turning those pesky tapers and then turn end for end to do the lower portion.. now relying on the mic and my turning skills (HA!) it was time to part off… well my faith in my parting such a thin bit of brass was not great so hacksaw ( chuck board in place.. and a nod to Mr John of twastard engineering) I parted off.. eager to try the bearings and cut the thread halfway up only to find the slackness in all the bearing surfaces. I can only put this down to poor measurement and the spring in the stock from turning between centers..

AT LONG LAST I get to the cry for help, could any kind soul with more experience like to suggest another way of manufacturing this component on a rather old Myford ML7 with 3+4 jaw chucks, ER collets. NO traveling steady…

many thanks in advance Martin.