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  1. #886
    Join Date
    Nov 2017
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    Geelong, Australia
    Age
    57
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    2,651

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    2 things

    I need a new parting holder, as this isn’t going to buff out…



    Secondly - I probably need to improve my parting technique

    Steve

  2. #887
    Join Date
    Nov 2017
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    Geelong, Australia
    Age
    57
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    2,651

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    Make that 3 things.

    Looking for some more M12x1.75 nuts for clamping on the mill.

    These leftover flange nuts from the shed build are perfect!



    Steve

  3. #888
    Join Date
    May 2011
    Location
    Murray Bridge S Aust.
    Age
    71
    Posts
    5,942

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    How many more do you need???
    Kryn
    To grow old is mandatory, growing up is optional.

  4. #889
    Join Date
    Mar 2011
    Location
    Southern Flinders Ranges
    Posts
    1,536

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    Quote Originally Posted by OxxAndBert View Post
    2 things

    I need a new parting holder, as this isn’t going to buff out…



    Secondly - I probably need to improve my parting technique

    Steve
    It’s up there with the slitting saw I buried a few months ago…
    Attached Images Attached Images

  5. #890
    Join Date
    Sep 2012
    Location
    York, North Yorkshire UK
    Posts
    6,436

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    Hi Bob,

    If you have a rounded edge stone or even a small round one you can soon put an edge back on to the tap ! Carefully rub down the flutes several times. Not really practical on a spiral one.
    Best Regards:
    Baron J.

  6. #891
    Join Date
    Jul 2021
    Location
    Europe
    Age
    30
    Posts
    36

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    I learned that a wavy patterned metal plate with a cracked surface is called steel clad, its some fancy type of abrasion resistant metal plate where high-carbon chrome (steel alloy?) is welded on top of steel, this makes for a very interesting look and very high abrasion resistance, costing just under 10 euros per kg, i have never even heard about this thing before and i thought i had seen it all.

  7. #892
    Join Date
    Jul 2021
    Location
    Europe
    Age
    30
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    36

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    Quote Originally Posted by BobL View Post
    Today I had to tap 16 M8 holes in 5mm thick SS plate.
    my take would be to either drill slightly larger holes so you dont have to cut as much material, since the material is hardened it should make for extra strong threads anyhow- or go all the way and heat the whole thing up until redhot and then leave it to calm down in some sand to remove the hardening
    really most threads dont need to have the strenght they do, M12 thread requires 10.2 hole, but you can plenty fine go with 11mm hole for most, probably even 11.5 just to hold things into place

  8. #893
    Join Date
    Oct 2008
    Location
    N.W.Tasmania
    Posts
    1,407

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    Quote Originally Posted by Zeth4500 View Post
    my take would be to either drill slightly larger holes so you dont have to cut as much material, since the material is hardened it should make for extra strong threads anyhow- or go all the way and heat the whole thing up until redhot and then leave it to calm down in some sand to remove the hardening
    really most threads dont need to have the strenght they do, M12 thread requires 10.2 hole, but you can plenty fine go with 11mm hole for most, probably even 11.5 just to hold things into place


    Welcome to the forum Zeth4500, I'm not sure whether you realise it or not but this is an Australian based forum, and although we welcome members from all over the world, most here are Ausies with an Australian perspective on things.You will have stuff over there which we rarely see and visa versa, and of course there will be a lot we share in common. There are a great bunch of people on the forum and you will get lot of help and advice should you need it, and of course if you feel that you may have an answer for some of us, don't be shy, we would love to hear what advice you have to offer.

    Assuming 12X 1.75 mm threads, 11.5 mm tapping drill size would stop your workpiece from rolling off the bench, but not very strong for much else, with 22% engagement. 11mm gives 44% which would probably hold for most stuff ok, while 10.5 mm tapping drill gives 66% which is probably close to where you would want to be. With 12 X 1.25 metric fine threads, the figures of 11.5mm tapping drill will leave you with 31%, 11mm will give you 61.6%, and a reduction of just 0.1mm to 10.9mm gives 67.7% thread engagement, and in 316 SS, I would not like to be trying any better than that if I only had a blunt tap to thread with.

    That wavy patterned metal plate that you mentioned in your other posting sounds like a product they used for lining bull dozer blades, and I think that it may have been called "Duo- Plate". It was a low carbon steel plate with a layer of much harder steel on top, like a continuous hard facing. The soft low carbon under layer allowed the combination to be shaped in rollers to the curve required to fit a dozer blade for example, without shattering like it would have had it had no softer layer holding it all together. No doubt someone who really knows what's what will correct me if I have messed up in my information, and then we'' both will be the wiser for it.
    Last edited by Ropetangler; 25th Jul 2021 at 11:53 AM. Reason: Improved the grammar.

  9. #894
    BobL is online now Member: Blue and white apron brigade
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    Perth
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    Quote Originally Posted by Zeth4500 View Post
    my take would be to either drill slightly larger holes so you dont have to cut as much material, since the material is hardened it should make for extra strong threads anyhow- or go all the way and heat the whole thing up until redhot and then leave it to calm down in some sand to remove the hardening
    really most threads dont need to have the strenght they do, M12 thread requires 10.2 hole, but you can plenty fine go with 11mm hole for most, probably even 11.5 just to hold things into place
    Funny you should mention annealing because what I was making was wheel brackets for a trolley/bench for a small furnace that would have been perfect for that annealing job. I don't have any other way to heat up the size of metal involved.
    Wheel mpount.JPG

    RE: use a larger drill.
    Yeah I do that quite often and did think of that afterwards, especially when I looked up the detailed drill for tap chart on my laptop and realised the 6.8mm hole I used gave about an 85% engagement. I need to print that out and put it up in my shed.

  10. #895
    Join Date
    Nov 2008
    Location
    North Brisbane. Qld. Australia
    Age
    70
    Posts
    1,511

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    Making brackets to mount side steps to my brothers ute. Plates cut and drilled. Angle mostly cut and drilled. Went to cut last two lengths of angle to correct length and ended up with one piece the wrong way around so cut off the wrong end. Trouble is I don't have another piece long enough so have to buy more tomorrow. I learnt not to rush when you are almost done.
    Nev.

  11. #896
    Join Date
    Aug 2011
    Location
    Melbourne
    Posts
    4,779

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    Bought a cheapie indexable carbide part off tool recently and used it today.

    What a pleasure to use! Cant believe I've been missing out all this time. I was coy at first (bad experiences early on in my Metalwork hobby have scarred me) but in the end I really pushed it quite firmly and it just cut like butter. Works nice on both ms and aluminium. Yet to try it on SS.

    Simon

    Sent from my SM-G970F using Tapatalk
    Girl, I don't wanna know about your mild-mannered alter ego or anything like that." I mean, you tell me you're, uh, super-mega-ultra-lightning babe? That's all right with me. I'm good. I'm good.

  12. #897
    Join Date
    Jan 2004
    Location
    Mackay North Qld
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    6,446

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    I learned today that the hashtag key # is not a good pick as part of an internet password.

    The reason is that this key is an option (at least on an iMac keyboard ) and often you get £ when it is used.

    If you type into a blank password box where dots are shown instead of what you see is what you get,you can't tell that the key has printed a £ instead of #.

    You are positive you pressed the # key but the so and so typed £. Option key 3 changes that.

    It does not become obvious until typed out into a document.

    It took a while until the penny dropped.

    Grahame

  13. #898
    Join Date
    Aug 2011
    Location
    Melbourne
    Posts
    4,779

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    Quote Originally Posted by simonl View Post
    Bought a cheapie indexable carbide part off tool recently and used it today.

    What a pleasure to use! Cant believe I've been missing out all this time. I was coy at first (bad experiences early on in my Metalwork hobby have scarred me) but in the end I really pushed it quite firmly and it just cut like butter. Works nice on both ms and aluminium. Yet to try it on SS.

    Simon

    Sent from my SM-G970F using Tapatalk
    Used it on stainless. Works well, usual caveats with SS as in keep pushing the tool in order to cut and not work harden the material.

    All in all, pretty good.

    Sent from my SM-G970F using Tapatalk
    Girl, I don't wanna know about your mild-mannered alter ego or anything like that." I mean, you tell me you're, uh, super-mega-ultra-lightning babe? That's all right with me. I'm good. I'm good.

  14. #899
    Join Date
    Aug 2019
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    Revesby - Sydney Australia
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    56
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    Learnt that the fastest way to enlarge a hole isn't the best, and that what should produce consistent results doesn't for really weird reasons.


    Someone wants to modify some washers so they fit over some little socket head screws.
    8mm ish hole, 316 stainless. I measure the head dia., 8.66mm.
    11/32 drill should give clearance?

    Throw a washer in the lathe. 11/32 in tailstock chuck. Push it through. Try the screw head.
    No. Close, but not enough. Go up to 9mm drill. Push it through. Check with the head.
    Yep, plenty. OK. Think about the fastest way to do all 80ish washers.

    I could maybe put 2 or 3 washers in the front 2 or 3 grooves in the chuck,
    and tighten them enough to drill them in one operation?

    Take first drilled washer out, notice there is a significant burr on the back.
    Hmmm. Stainless. Try a deburring tool. Doesn't touch it.
    Also no way I can de-burr that with a chamfer tool.

    Try the bench grinder. Holding washer too loosely. It flies into the sheet metal wheel cover.
    Grrr. Fish it out, grind burr off, have a think.


    Looks like I am boring all 79 remaining washers.
    IMG_4149.jpg IMG_4150.jpg IMG_4151.jpg




    Now, you would think I could set the cross slide, push the boring bar through,
    do a second (spring) pass, and it would be consistent. Right?


    No. Every few washers I tested the socket head through the bore, and every few would get a bit tighter.
    So I would adjust the slide out a thou, and re-cut.

    Either something is moving, or my little CCMT06 insert was wearing?
    (no coolant, but it is only boring 1.5mm deep at .35-ish-mm DOC?)
    DRO said cross slide was locked well, so I guessed wear.

    I tried faster spindle (from 300 to 500 to 1200rpm), I tried slow feed, I tried one initial cut and two spring passes, I tried gripping the boring bar ridiculously close, but still it would be cutting less each time.


    By about washer 70, I had got a good rhythm;
    • Socket head in machined washer with right hand
    • If it fitted OK, left hand chuck key, take it out.
      Throw washer+socket head screw in finished parts tray.
    • Fresh washer with right hand, into chuck grooves, decent nip.
    • Chuck key away. Left hand on "inch button". Bore till just through washer.
    • Ignore fact that cutter is still squealling. Carriage back out, then back in until quiet.
    • Carriage away. Left hand off inch button, grab chuck key. Right hand for socket head screw.



    In the end, it seems like boring just deep enough before trying again with the second (spring) pass gave me consistent results. If I bored deeper the first time, and I mean 1.6mm instead of 1.5mm, it would always be a little undersize after the spring pass.

    Very weird. Might be something to do with a stringy burr/ring being pushed through to the back of the hole, and somehow rubbing on the blunt corner radius of my cutting insert.
    Nigel, from a cave FULL of unfinished projects and lost tools.

  15. #900
    BobL is online now Member: Blue and white apron brigade
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    Feb 2006
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    Perth
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    FWIW I've stacked a bunch of washers up inside collet chuck insiders to hold them while boring them out.

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