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  1. Replies
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    . most cnc can do .0004" flatness and waviness...

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    most cnc can do .0004" flatness and waviness BUT when part is unclamped or chucked it may warp or spring out of flatness. especially if part has not been annealed or stress relieved
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    also...
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    . 1) usually dont use same size end mill as the...

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    1) usually dont use same size end mill as the slot that is usually rough slot leave material on sides and bottom then take finish cut to improve surface finish and slot size consistency
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    2)...
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    easier to use machinerys handbook. usually use...

    easier to use machinerys handbook. usually use chart, make copy and keep at machine when doing a job if worried about handbook getting dirty or wet .
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    some free tool catalogs will also have chart...
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    . most important thing is length of drill bit...

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    most important thing is length of drill bit stickout and length of tool holder. obviously depending on part and setup you might need a long drill to reach even when hole is not that deep. or you...
  5. burning vegetable oil most likely creates many...

    burning vegetable oil most likely creates many bad or dangerous fumes too. just cause its natural dont mean its harmless.
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    mushrooms are natural and many are extremely toxic.
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    i would worry...
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    . length to dia ratio of drill is the most...

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    length to dia ratio of drill is the most important thing. you can have somebody drill a million shallow holes per days no problems and then drill deep holes and start having massive broken drill...
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    about .004" per foot common for setting machinery...

    about .004" per foot common for setting machinery and shim calculations as obviously if 10x more sensitive you end up being off scale and not getting any reading to be able to calculate shims.
    i...
  8. . obviously you can adjust rpm and feed rate if...

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    obviously you can adjust rpm and feed rate if limited hp. or use a pilot spade drill say 1.5" dia before going to a 2.5" drill. yes for 1018 steel figuring 1hp to remove 1 cubic inch per min is...
  9. point is if you want part flat in relaxed...

    point is if you want part flat in relaxed "unclamped" on its airy points or minimize sag from its own weight. thick sheet metal supported on its ends sagging. if done on a horizontal mill on a angle...
  10. . i usually get jig or fixture plate usually its...

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    i usually get jig or fixture plate usually its 6061 T0 or annealed and its usually fairly flat as is. but its strength or tensile strength is much less. 7075 usually for higher strength...
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    maybe get coolant bacteria dont like. often...

    maybe get coolant bacteria dont like. often coolant ph is 9 or 10 and a device like aquarium air pump bubbles air through it all day long. maybe change coolant once a year cause it gets oil mixed in...
  12. 1) every day medium size castings like that are...

    1) every day medium size castings like that are milled to .0004" per 40" flatness. usually indicate or probe before removing from table. waviness of <.0003" TIR is commonly expected
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    2) normally...
  13. . unless annealed rather than T6 you have like...

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    unless annealed rather than T6 you have like 99.9999% chance it will easily be not flat over .001" and .050 to .100" warpage after machining not unheard of. and of course machined plate will often...
  14. Thread: Recession?

    by DMF_TomB
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    26,218

    . ironic Fuji doing much better than Kodak cause...

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    ironic Fuji doing much better than Kodak cause they invested in making many things becoming a bigger company not selling parts of the company.
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    Steve Jobs wasnt perfect much obviously Apple...
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    . sandpaper even when trying to remove .0001"...

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    sandpaper even when trying to remove .0001" takes a lot of effort. obviously I have had to remove .0001" from surfaces before over the decades.
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    if rough surface needed for adhesive bonding...
  16. Thread: Recession?

    by DMF_TomB
    Replies
    303
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    26,218

    technology change from internal combustion...

    technology change from internal combustion engines and pollution control devices on automobiles to electric vehicles using electronics rather than complex transmissions will have a Massive effect in...
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    . . typically when rougher finish wanted for...

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    typically when rougher finish wanted for applying epoxy you machine at much higher feed rate. rather than .0030" ipt or less you got .010" to .030 ipt feed. or use a corncob or serrated type...
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    . some places sell end mills with 90 degree...

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    some places sell end mills with 90 degree point or ends for drill, chamfer and milling. obviously it depends on length to diameter ratio
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    typically when over 3x or over 3x dia in length tool...
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    advantage with a different work offset for each...

    advantage with a different work offset for each part is when each part is probed and different work offset used for each part. the probing can get exact location on specific features like a bore or...
  20. . i find when i engrave a part i use a sharpie...

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    i find when i engrave a part i use a sharpie marker tool holder 1st. nothing worse than engraving parts with spelling errors. by looking at sharpie marking 1st i often catch spelling errors before...
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    caustic ultrasonic cleaning, rinse than...

    caustic ultrasonic cleaning, rinse than passivating treatment is common on stainless steel parts. it actually makes then more resistant to rusting
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    hot caustic breaks down organic carbon based...
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    excel

    Excel does math and the math can include many factors
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    sudden tool failure often can have a random factor. that is for every 100 parts you can have 99 parts with no tooling problems. BUT the 1...
  23. as anybody with a copy of the Shiyong Wujin...

    as anybody with a copy of the Shiyong Wujin Shouce (standard hardware handbook) knows most items are made to Chinese government GB standards
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    advantage being if made to government standard than in...
  24. a simple (usually free) excel spread sheet works...

    a simple (usually free) excel spread sheet works better. operator records machining times and reason for delays. then after months to years you can easily see delays and reasons why. for example...
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    . 1) some machines have more trouble at certain...

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    1) some machines have more trouble at certain rpm, for example max rpm in low gear. if machine goes into high gear at 700 rpm you might have more trouble tapping at 600 to 700 rpm
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    2) same with...
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