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  1. #1
    Join Date
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    Default Screwcutting to distraction.

    I am wondering how others get on when machining in company. As a rule I don't. When it comes to screwcutting I even turn the music off.

    Yesterday, one of my mates returned with a neat 4" Record " Motor" engineers vice I had sold him a fortnight ago. The vice was in fine condition at the time of the sale but my mate decided to strip it down and give it a clean and polish. He even removed the jaws and that's where he came unstuck. Reinstalling the jaws, he managed to shear the head off one of the screws while tightening it with a square shank screwdriver and a cresent. He rang me and described the screw. It was countersunk but had a steep taper and the thread was about 8mm in diameter. I said I would make a new screw.

    The thread was 5/16" BSF (22tpi) and the included angle of the head was a strange 33 degrees. All easy enough. The head diameter was 1/2 " and I had some 1/2" 4140 that I thought would do the job.

    Turned the bar down to 0.3125" and cut the chamfer. I had decided to cut a narrow run out groove and to cut the thread by hand with my spindle mandrel and crank rather than power feed . The thread length was 1/2", the depth of the thread, 0.0291" The run out groove was located at the commencement of the taper. Not a lot of room for error.

    Now my mate was talking. If it wasn't about what I was doing it was about his car and his maintenance of it. I get distracted easily. Ipods on the bus distract me. The woman I sit next to at work telling me about her family for eight years straight distracts me. Distracts is me being polite.

    Then there was the annoyance of not having anything to test the fit of the thread while the screw was in the chuck. I had to remove it from the chuck, check the fit and then pick up the thread again with a loupe. The thread in the vice had been slightly distorted, making things a touch trickier.

    Maybe it was the frustration having to cut the screw in the first place, maybe the distraction of the banter, maybe it was me being crowded in next to my lathe by my mate watching me screwcutting. I don't know why but for some reason that I still can't fathom, I TURNED ON THE POWER.

    A Hercus 9 has a top speed of a sluggish 700 rpm. Cutting a half inch long thread with a run out groove 30 thou wide is attention demanding even at the slowest back geared speed of 60 rpm. I couldn't do it at 700 rpm. My lathe is fitted with high speed pulleys. I had been cutting at 1800 rpm before I started the screwcutting by hand. The lathe remained set up for 1800 rpm.

    The half nuts were closed when I hit the switch. I sheared off the entire end of the carbide inset and the tip of it's support shim when it carved its way into the chuck jaws.

    I had to ask my mate to stop talking when I was slotting the screw head on the Schaublin mill.

    I imagine that there are blokes who enjoy the company of others while undertaking tasks in the shed. Maybe I'm turning into an old cantankerous prick, but I'm not one of them.

    BT

    p.s. I turned off the mess on the TOS jaws.

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  3. #2
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    Aug 2008
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    Default

    Agree 100%. Two things in life really get me hot under the collar, people talking to me while I'm welding or machining and people who insist on chatting to me while I'm sitting in the form-up area ready to go out on the race track. I would have thought the helmet visor being down and the total lack of response from me would give them a hint but obviously it ain't so.

  4. #3
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    Default

    im a bit like you if im bending and welding up roll cages i dont have a problem with a mate there .
    however when im bolting together a race motor either for myself or one of the teams i look after i usually wait till eveing leave the mobile in the house and shut up the workshop and tell the mrs if anyone comes around im not home . thats one job i need to concentrate and dont like any distractions altho i dont mind some quite music in the background,

    so no i dont think your getting old and cranky i fully understand there are just some jobs that require your full attention end of story .and if there real mates they will understand mine know not too bother me when im doing engine work i tell them the engine im distracted on might be theres lol .

    cheers dean

  5. #4
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    Bob,
    Photos or it didn't happen: just joking . I prefer the solitude of the shed at such times cause when I stuff something up bad no one wants to be around to hear the cussing. Brain fades are just part of advancing years I feel

  6. #5
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    Hi,

    I agree with you 100%. Don't talk to me when I'm working on machines, its too easy to stuff something up.
    A place I worked at had a perfectly good large lathe until someone was doing a job on it whilst talking to someone else and crashed the toolpost/carriage into the chuck at high speed. Chuck is now out 30 thou (by memory).

    Ben

  7. #6
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    Quote Originally Posted by C-47 View Post
    Bob,
    Photos or it didn't happen: just joking . I prefer the solitude of the shed at such times cause when I stuff something up bad no one wants to be around to hear the cussing. Brain fades are just part of advancing years I feel
    I'm having trouble imagining you cussing Alan. You strike me as a placid bloke.

    Now, my mate has heard me arc up before. We worked in the same office. After my performance yesterday, I don't reckon he will be asking me to fix anything else!

    I destroyed the tips of 2 inserts with my ambitious narrow run out groove ( a foolish decision given the sticky nature of 4140). We have crows around here. Vicki knew it wasn't one of those critter's mating calls when she heard the screaming emanating from the shed when I sheared off the third tip.

  8. #7
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    Default Disaster

    Quote Originally Posted by Anorak Bob View Post
    I'm having trouble imagining you cussing Alan. You strike me as a placid bloke.

    Now, my mate has heard me arc up before. We worked in the same office. After my performance yesterday, I don't reckon he will be asking me to fix anything else!

    I destroyed the tips of 2 inserts with my ambitious narrow run out groove ( a foolish decision given the sticky nature of 4140). We have crows around here. Vicki knew it wasn't one of those critter's mating calls when she heard the screaming emanating from the shed when I sheared off the third tip.
    Bob
    I just read your report on the disaster, & as I read it a loud scream came out of me to the tone of "Oh No" or words to that effect.
    I have been on the lathe this morning finishing off the Chuck Stops, & just walked into the house thinking how good it is to have peace & quiet in the solitude of the workshop. Maybe its got a bit to getting older, like your goodself, but I do not have anyone in the workshop while these jobs are going on.
    I just tell them to "leave the job with me, so I can get to it when I have time"
    That seems to work.
    I was just going to phone you, so maybe I should do that, so you can "Offload & debrief"
    These are the methods I have applied from "Steamwhisper Phils Therapy Classes"
    which help a lot
    regards
    Bruce

  9. #8
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    I can't function with distractions and have learnt to not distract others on machine tools unless they start the conversation first. That said, a machinist I know who started in a large organisation while working in a large shed full tradesmen isn't bothered in the slightest: in that environment, showing any sign of distraction is only encouragement for d**khead co-workers. He displays an almost Zen-like concentration in spite of grinder noise and blaring radios.

  10. #9
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    So Bob did you break 2 additional insert tips by using the unusual manual method of screw cutting.
    When you normally use this method do you have tension on the counter shaft belts or have them loose.

  11. #10
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    Quote Originally Posted by pipeclay View Post
    So Bob did you break 2 additional insert tips by using the unusual manual method of screw cutting.
    When you normally use this method do you have tension on the counter shaft belts or have them loose.
    The belt was loose Peter. The run out groove needed to be a touch wider but as it turned out, a lot deeper also. I had zeroed the cross slide against the 5/16" section of the bar then cut a groove about 32 thou deep. A whisker more than the depth of the thread. In theory it should have been OK. In reality it wasn't. The tapped holes in the vice jaws would not accommodate the screw machined to the theoretical depth. I ended up cutting the screw about 6 thou undersize to get it to fit. And therein lies my problem, the run out groove was not deep enough. I was flustered and off at that stage. I should have told my mate to bugger off and talk to my wife while I focused on the job. I can't multi task. Having a bloke tell me about the nuances of Holden's fuel injection system while I'm trying to remember the depth of the last cut proved too much.

    The hand turning is something I have utilised for cutting a thread to a shoulder and for metric threading. Yesterday I did it because of the taper. I simply stuffed up.

    Bob.
    Last edited by Anorak Bob; 30th June 2012 at 03:09 PM. Reason: spelling error -

  12. #11
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    For me it depends on the level of complexity that the task presents to me. For things that are complex to me, I can't even tolerate the radio. Unfortunately much of my time spent in the shed is when I'm at home with my 4 yo daughter. I'd be lucky to get 3 hours a week alone in my shed purely owing to family lifestyle. Still, when I do get the nod of approval from the GW to "disappear" for a few hours, I love it! I drift off into my own little world. SOmetimes it's very productive, other times I jut potter around deep in thought enjoying my cave and my own company.

    As for people in general watching me work, be it lathe, mill, whatever, I freakin hate it!

    May I also add that being rushed or working to a timeframe (if we have to go out or whatever) can be equally or even more distracting!

    Cheers,

    Simon

  13. #12
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    Hey Anorak Bob you'll have to learn to thread without a "run out" groove, it's really easy if you have a slow spinning spindle, ESPECIALLY when manually turning it.

    Sorry bout the disasters, sometimes it's best to say "leave it with me and pick it up tomorrow" or some such, or "I have a headache now, will do it later", or "I have a headache, so not tonight"

    Cheers.
    If I'm not right, then I'm wrong, I'll just go bend some more bananas.

  14. #13
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    Ueee is offline Blacksmith, Cabinetmaker, Machinist, Messmaker
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    Default

    Quote Originally Posted by Log View Post
    "I have a headache, so not tonight"

    Cheers.
    Since when has a man ever said that?

    Luckily I am used to working in a noisy workshop from the days of being a cabinetmaker, and I have the same Zen like abilities as the guy Mark knows. I could have music full blast and when I stop concentrating I couldn't even tell you what was playing. Having said that like Simon I usually have Arthur around to keep an eye on but he is pretty good at looking after himself for those times of deep concentration.
    1915 17"x50" LeBlond heavy duty Lathe, 24" Queen city shaper, 1970's G Vernier FV.3.TO Universal Mill, 1958 Blohm HFS 6 surface grinder, 1942 Rivett 715 Lathe, 14"x40" Antrac Lathe, Startrite H225 Bandsaw, 1949 Hercus Camelback Drill press, 1947 Holbrook C10 Lathe.

  15. #14
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    Quote Originally Posted by Log View Post
    Hey Anorak Bob you'll have to learn to thread without a "run out" groove, it's really easy if you have a slow spinning spindle, ESPECIALLY when manually turning it.

    Sorry bout the disasters, sometimes it's best to say "leave it with me and pick it up tomorrow" or some such, or "I have a headache now, will do it later", or "I have a headache, so not tonight"

    Cheers.
    Hey Log,

    I have tried my hand at run out groove-less threading before and maybe before I was just lucky. Posting a thread like this does suggest that I have NFI but it was more about working with or without distraction. All I wanted to do yesterday was get the job done. Maybe I should have given my mate his dough back and fixed the thing at my leisure.

    Hand threading has been useful for shoulder work such as the 1 1/2" x 8 threads below and for the metric threads on my travel stops for the mill. The

    Bob

  16. #15
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    Hi Bob,
    Same here. Thinking back I am not sure anyone has ever seen me screwcutting in a lathe. I refuse to continue if someone comes anywhere in the vicinity of the shed. It is one aspect of machining that requires max concentration especially for me as I rarely if ever use a runout groove.

    Phil

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