Machining a Hardened Ball Screw - Viewer Sent in This Job - Manual Machining

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  • เผยแพร่เมื่อ 20 พ.ย. 2024

ความคิดเห็น • 150

  • @andrewterry8092
    @andrewterry8092 ปีที่แล้ว +30

    Josh, your videos have really improved lately, thanks for sticking with it.

    • @TopperMachineLLC
      @TopperMachineLLC  ปีที่แล้ว +13

      Thanks. I've taken a slightly different approach to editing. Having good cameras and audio doesn't hurt either.

    • @ypaulbrown
      @ypaulbrown ปีที่แล้ว +3

      outstanding....@@TopperMachineLLC

  • @ChuckNorriz1122
    @ChuckNorriz1122 ปีที่แล้ว +13

    I’m 56 and have never done machining but I learn something new every time I watch your videos. Today was annealing metal. Thanks for that!

    • @TopperMachineLLC
      @TopperMachineLLC  ปีที่แล้ว +3

      Thanks. I learned a bunch also doing this job. I've never annealed one before, but got under the hardness and cut. Glad my customer had this info for me.

  • @aquilifergroup
    @aquilifergroup 3 วันที่ผ่านมา

    Annealing prior to machining a hardened piece . Learned something new today. Thank you

  • @natedoerfler652
    @natedoerfler652 ปีที่แล้ว +6

    Nice to have a good drawing like that!

  • @timscartoys9321
    @timscartoys9321 ปีที่แล้ว +8

    I have always enjoyed watching work being machined, and with your descriptions, I could watch all day!!

  • @bernardwill7196
    @bernardwill7196 ปีที่แล้ว +1

    This Vernier a real beauty !! Greeetings from Germany.

  • @BruceBoschek
    @BruceBoschek ปีที่แล้ว +3

    Very interesting. Excellent video quality, btw. Thanks for letting us look over your shoulder. Have a good weekend.

    • @TopperMachineLLC
      @TopperMachineLLC  ปีที่แล้ว +1

      Thank you! I've been working hard to improve the channel

    • @BruceBoschek
      @BruceBoschek ปีที่แล้ว +1

      @@TopperMachineLLC Much appreciated!

  • @TheUncleRuckus
    @TheUncleRuckus ปีที่แล้ว +6

    Great video as always Josh! Also thank you to Bill for sending in this job and giving us some good content to watch. 👍👍

    • @TopperMachineLLC
      @TopperMachineLLC  ปีที่แล้ว +1

      He has more for me to do. I'll film as much as I can.

  • @michaellehmann280
    @michaellehmann280 ปีที่แล้ว +8

    Great video Josh! Love that beast of a caliper!

    • @TopperMachineLLC
      @TopperMachineLLC  ปีที่แล้ว +1

      Thanks. It sure is fun to bring that one out.

  • @ellieprice363
    @ellieprice363 ปีที่แล้ว +3

    Tee shirt suggestion. Caliper photo with the words, “I’ve got a fifty incher and I know how to use it!”

  • @dc5723
    @dc5723 ปีที่แล้ว +3

    That's an awesome project and yes, the Starette is a thing of beauty.

  • @ypaulbrown
    @ypaulbrown ปีที่แล้ว +1

    Good Morning Josh.....always love your content.....best wishes from Florida, Paul

  • @jasonhull5712
    @jasonhull5712 ปีที่แล้ว +1

    Nothing beats a good quality machine with a nice sharp tool. Love it 👍

  • @bruceferrero8178
    @bruceferrero8178 ปีที่แล้ว +5

    Nice work! We have a 50 inch Starrett caliper at work, we call it Excalibur 😉 !

    • @TopperMachineLLC
      @TopperMachineLLC  ปีที่แล้ว +4

      Nobody better be swinging Excaliber around. They aren't cheap!

    • @bruceferrero8178
      @bruceferrero8178 ปีที่แล้ว +2

      @@TopperMachineLLC oh heavens no! Haha 😄

  • @geckoproductions4128
    @geckoproductions4128 ปีที่แล้ว +1

    Josh: really like watching your machining techniques, thanks

  • @bostedtap8399
    @bostedtap8399 ปีที่แล้ว +3

    Nice job on tempering Josh, always love that design of collet chuck.
    Thanks for sharing

  • @warrenjones744
    @warrenjones744 ปีที่แล้ว +4

    Well done Josh. recently I just had a job I needed to anneal a hard end like that and that's exactly what I decided to try, I figured I had nothing to lose. I heated it till it was just blue and let it cool. Worked the treat, the part that needed to stay hard stayed hard too. I have a hardened BT-30 tool shank I need to make a custom deal on the end and will try the same thing. It's knowing those little tricks and when you can use them that make things so fun and less frustrating.

  • @Unrivaledanime
    @Unrivaledanime ปีที่แล้ว +1

    Thanks Josh

  • @edsmachine93
    @edsmachine93 ปีที่แล้ว +3

    Very nice and interesting job Josh.
    Well done and thanks for sharing.
    Have a great day.👍👍

  • @gofastwclass
    @gofastwclass ปีที่แล้ว +4

    Another excellent job! Thanks for sharing Josh.

  • @Farm_fab
    @Farm_fab ปีที่แล้ว +1

    Josh, a sub course in my welder training was for hardening and annealing, and has been good information. I designed a tool for an employer, and it required annealing a slot in a piece of OTR leaf spring steel to weld it to a 1" shank. It held up for many years.

  • @davidpeterson5186
    @davidpeterson5186 ปีที่แล้ว +1

    Send, cut, send Topper style, very good video!

  • @johnw.peterson4311
    @johnw.peterson4311 6 หลายเดือนก่อน

    Josh, thank you for this video. You do great work and are a great teacher.

  • @michaelweatherhead9470
    @michaelweatherhead9470 ปีที่แล้ว

    Thanks for the video Josh well done 👍❤❤ it. Take care of yourself and family and be Blessed ❤️❤️.

  • @jasonhull5712
    @jasonhull5712 ปีที่แล้ว +2

    What a great little job. And you do an amazing job of breaking all the cuts down and how and why. Very interesting and inspiring video. I truly enjoyed this one from the beginning to the end. Thanks for sharing your processes and methods.

  • @richardsurber8226
    @richardsurber8226 ปีที่แล้ว

    Thanks for the very technical manual turning. Good video Topper

  • @nobuckle40
    @nobuckle40 ปีที่แล้ว +2

    Always enjoyable to watch your work. Those calipers were the star of the video.

    • @TopperMachineLLC
      @TopperMachineLLC  ปีที่แล้ว +2

      They are definitely cool, and locked up when not in use.

    • @BrucePierson
      @BrucePierson ปีที่แล้ว +1

      @@TopperMachineLLC Must be worth a small fortune, a few k maybe?

    • @TopperMachineLLC
      @TopperMachineLLC  ปีที่แล้ว +2

      @@BrucePierson last I saw was around $6K a few years back.

  • @kentuckytrapper780
    @kentuckytrapper780 ปีที่แล้ว +2

    Great video Josh, I use the anchor lube myself, note clean up all parts that come in contact tools vise it will stain, but it's my go to for hard turning...

    • @TopperMachineLLC
      @TopperMachineLLC  ปีที่แล้ว +2

      I found that out right away. Great product, that is the only downside.

  • @ivanolsen8596
    @ivanolsen8596 ปีที่แล้ว

    Annealing is a great tool, I use it mainly on copper washers to remove the vibration induced brittleness on diesel injector seating washers. The verniers are certainly something to behold! Now I will spend the rest of my life looking for comparable micrometer!!!!!

  • @uther10
    @uther10 ปีที่แล้ว

    Thanks Bill and Josh!

  • @THEIRONWORKER
    @THEIRONWORKER ปีที่แล้ว +1

    When I anneal, I turn the part red and bury it in wood ash until it cools. And then do the work. I will have to try this method out . Nice video

    • @bostedtap8399
      @bostedtap8399 ปีที่แล้ว

      Josh was tempering the part, not annealing , just bring down the previously hardened and tempered shaft to a lower hardness value. Guessing from 50 to 58 hardness Rockwell C (HRC), to 30 to 35 HRC.

    • @jeffreywhitmoyer860
      @jeffreywhitmoyer860 5 หลายเดือนก่อน

      ​@@bostedtap8399 I was going to make the same comment. The process is actually a temper. Heating to a blue like that probably puts it into the 700-900f range. In this case the light blue would suggest closer to 700, at 900 the color would be more violet. Not much higher than 900 you would start developing a light scale. 700-900 can be a dangerous range for some alloys as something known as temper embrittlement can occur. It's most common in 410 & 420 martensitic stainless steels.

  • @GardenTractorBoy
    @GardenTractorBoy ปีที่แล้ว +1

    This was an interesting project. The drawing was great and it must have been easier than working from a scrap of paper

  • @emilgabor88
    @emilgabor88 ปีที่แล้ว +1

    For snap ring grooves, ER inserts for like threading. They make also for grooves. Hss if you resharpen go too small and you cant go left or right because they deflect.

    • @TopperMachineLLC
      @TopperMachineLLC  ปีที่แล้ว +1

      I have many different inserts for grooving, just none this size. Definitely going to order a box soon.

  • @3PurpleSquirrels
    @3PurpleSquirrels ปีที่แล้ว +2

    Interesting video as always. Going to be saving some this one to to share with the new design engineer always good to see how a drawing in interpreted when making the part.

  • @kylezellmann6811
    @kylezellmann6811 ปีที่แล้ว +1

    Well done, that annealing temp could have helped me in a lot of projects!

  • @alanm3438
    @alanm3438 ปีที่แล้ว +4

    Thanks for the video. First thing in the morning; good thing to wake up to. I do not do this kind of work so your videos are always educational. It is great that your standard is higher than what the print calls for.

    • @TopperMachineLLC
      @TopperMachineLLC  ปีที่แล้ว +2

      It's crazy to draw something like this with so many tolerance differences. Just makes sense to tighten up on my side.

  • @michelecrown2426
    @michelecrown2426 ปีที่แล้ว +2

    Great tutorial. My machinist brain couldn’t compute +/- 100 thou 😲. I’m like you I would have brought it to the actual dimension called out.

  • @frankkent8046
    @frankkent8046 ปีที่แล้ว +4

    Great video! Question, I watch CEE along with watching you and Kurtis, when doing induction hardened chrome bar, uses a ceramic insert to cut away the hardened area before switching back to carbide inserts and doing whatever is needed. Could you have used a ceramic insert to do this job, that way you didn't have to anneal the rod, and potentially causing a failure due to lack of hardness on the ends? Thanks

    • @TopperMachineLLC
      @TopperMachineLLC  ปีที่แล้ว +5

      Ceramic would not work in this instance. It would break in the interrupted cut of the thread. The screw was only hardened for the balls to roll in. Just a surface hardness. Annealing it will not affect the shaft long term. My customer said they wear out the screw, never break one. I have in the past turned induction hardened shafts with standard carbide. I just hand grind them to take the cut.

  • @ypaulbrown
    @ypaulbrown ปีที่แล้ว +2

    man, that Anchorlube is $2.31 an ounce......glad to see a demo on it working, thanks, Paul

    • @TopperMachineLLC
      @TopperMachineLLC  ปีที่แล้ว +1

      It's not cheap, but it sure does work good. It really doesn't take a lot either.

  • @paulgush
    @paulgush 5 หลายเดือนก่อน +1

    3:40 with that slow mo, my adrenaline got going. I thought we were headed for something breaking!

  • @markwatters6875
    @markwatters6875 ปีที่แล้ว +1

    Thanks for the video mate 👍🇦🇺

  • @StuartsShed
    @StuartsShed ปีที่แล้ว +1

    That 50 incher of yours is impressive. I thought my 24 inch tool was pretty good but seeing one that long in action is somewhat humbling.

    • @TopperMachineLLC
      @TopperMachineLLC  ปีที่แล้ว +1

      I've got 2 of the 24" ones and this thing is a beast. I'd love to get a 72", but I can't justify the expense.

  • @Paul-FrancisB
    @Paul-FrancisB 7 หลายเดือนก่อน

    Josh, I am sure that you gave the tolerancing on that drawing far more thought than the draftsman, that border was probably just cut and pasted from another part in CAD, not like the good old days on the drawing board when you had to consciously write everything by hand 😁

  • @jimsvideos7201
    @jimsvideos7201 ปีที่แล้ว

    Blue, noted. I have a few similar pieces and if I ever get to making something out of them this will be important.

  • @frankenscience3553
    @frankenscience3553 7 หลายเดือนก่อน

    thanks josh, you are reaching a small town in australia.

  • @hacc220able
    @hacc220able ปีที่แล้ว +1

    thanks for sharing

  • @thepotterer3726
    @thepotterer3726 ปีที่แล้ว +1

    Rather surprised that Anchorlube is a new product to you - Abom and others have been using it and plugging it for years.

    • @TopperMachineLLC
      @TopperMachineLLC  ปีที่แล้ว +2

      I honestly have little time to watch other's videos. I miss a lot of the content of the others. Definitely glad I found it, it's a great product.

  • @mfc4591
    @mfc4591 ปีที่แล้ว +2

    NO THAT IS A CALIPER, two man job to use that ! Thanks for the content.

    • @TopperMachineLLC
      @TopperMachineLLC  ปีที่แล้ว +1

      It is a beast!

    • @KenFullman
      @KenFullman 6 หลายเดือนก่อน

      It's the one Crocodile Dundee would have chosen.

  • @BrucePierson
    @BrucePierson ปีที่แล้ว +1

    That was an interesting job. Your "small" Vernier Caliper was pretty impressive. I think mine is 6", without going out and checking.

  • @mikeb1520
    @mikeb1520 ปีที่แล้ว

    I used to work for Schaeffler Group (FAG, INA bearings), when they needed to machine the ball screws they made, they were chucked in the lathe, coolant was put at the point they wanted it to remain hard, and then used a flame like you did to anneal it. I don’t recall what temperature they heated it to.

  • @redmorphius
    @redmorphius ปีที่แล้ว

    Always excited for a new video!

  • @jameswalshjr
    @jameswalshjr ปีที่แล้ว

    Question, when getting long stringy chips that were coming off when turning the shaft down to size. Should that be addressed? Different speed/feed or maybe an insert with different geometry? I've always understood that it's good practice to minimize long chips like that.

  • @rolandtamaccio3285
    @rolandtamaccio3285 ปีที่แล้ว

    ,,, luv the big vernier ,,, !

  • @valekx3197
    @valekx3197 ปีที่แล้ว

    Great video, how much can cost a job like this? thank you

  • @wmweekendwarrior1166
    @wmweekendwarrior1166 ปีที่แล้ว +1

    Good stuff

  • @xpim3d
    @xpim3d 2 หลายเดือนก่อน

    Is the collet chuck mandatory to do this type of jobs on lead screws? Thanks.

  • @lolcec81
    @lolcec81 ปีที่แล้ว

    Комментарий в поддержку канала и ролика, а также труда мастера....

  • @randydobson1863
    @randydobson1863 ปีที่แล้ว

    hello josh it's is randy and is cool thanks friends randy

  • @patrickflannery1143
    @patrickflannery1143 ปีที่แล้ว +1

    Good job

  • @6NBERLS
    @6NBERLS ปีที่แล้ว

    Most excellent.

  • @peterross6560
    @peterross6560 ปีที่แล้ว +1

    heating to blue is tempering, not annealing. annealing involves heating to critical temp, approx 1500 F and coooling slowly over several hours. Obviously, the tempering you have done is adequate softening for your turning but not completely softened. annealing would make it as soft as the steel can get.

    • @TopperMachineLLC
      @TopperMachineLLC  ปีที่แล้ว

      It did soften it enough to not be a problem for machining. Guess my terminology is wrong.

    • @peterross6560
      @peterross6560 ปีที่แล้ว +1

      I've enjoyed your videos for a couple of years, and always look forward to the next one. Keep 'em coming@@TopperMachineLLC

    • @TopperMachineLLC
      @TopperMachineLLC  ปีที่แล้ว

      @@peterross6560 Thank you for sticking with me. It has been a long bumpy road, but the channel is coming along nicely. More improvements coming.

  • @billjulian9496
    @billjulian9496 ปีที่แล้ว

    Josh, that annealing process is awesome, may I ask if it is steel species specific, ie, 4140, 4350 or 1065?

    • @TopperMachineLLC
      @TopperMachineLLC  ปีที่แล้ว +1

      I am not sure. First time I've done it. These are induction hardened, my guess is it would work with most grades of steel that is hardened

  • @AmateurRedneckWorkshop
    @AmateurRedneckWorkshop ปีที่แล้ว

    Great work looking 👀 good.

  • @Farm_fab
    @Farm_fab ปีที่แล้ว

    Josh, can you respline axles? I'm building a garden tractor, and am narrowing an SUV rear for it.

    • @TopperMachineLLC
      @TopperMachineLLC  ปีที่แล้ว +1

      That's a better job for grinding the splines. Those shafts are so hard, I don't think they would even anneal well. Years ago I swapped wheel hubs on a tandem axle truck. That changed the shaft length on me. We had a hell of a time cutting those down. Took longer to shorten and adapt axles than the rest of the job.

  • @ValiRossi
    @ValiRossi ปีที่แล้ว

    I wonder how far the ball nut has to travel towards the end of the screw. Sanding the threads could cause a problem.

    • @TopperMachineLLC
      @TopperMachineLLC  ปีที่แล้ว

      The hardness of these screws didn't allow for material removal. It was more a polish. From what the customer told me the ball nut never gets that close to the end.

  • @Daniel_en_el_trabajo
    @Daniel_en_el_trabajo ปีที่แล้ว

    amaizing as always!!! 🇦🇷

  • @garywalters4286
    @garywalters4286 ปีที่แล้ว

    Good video nice job on the shaft,When are we going to see some more sawmill videos?

    • @TopperMachineLLC
      @TopperMachineLLC  ปีที่แล้ว

      I was going to release it Tuesday, but a very dear friend passed and I am behind. I will release the 20 foot sawing on next saturday.

    • @BrucePierson
      @BrucePierson ปีที่แล้ว

      @@TopperMachineLLC Sad to hear about your friend. Condolences to all.

  • @thomaschandler8036
    @thomaschandler8036 ปีที่แล้ว

    Love your videos.....

  • @glennmoreland6457
    @glennmoreland6457 ปีที่แล้ว

    Great video
    ☹🇬🇧

  • @U_ever
    @U_ever ปีที่แล้ว

    "LIKE" button has been torqued to the manufacturer's recommended specification. "CLICK".
    God forbid you should be running around Spooner there with a loose "LIKE" button !

  • @blackbm54
    @blackbm54 ปีที่แล้ว

    Great video!

  • @firehousecustomfab3286
    @firehousecustomfab3286 ปีที่แล้ว

    What were you using to clean the blueing out of the treads.

    • @TopperMachineLLC
      @TopperMachineLLC  ปีที่แล้ว

      Very fine emery cloth.

    • @firehousecustomfab3286
      @firehousecustomfab3286 ปีที่แล้ว

      @@TopperMachineLLC ok. It looked almost like string, I wasn't sure. Thanks

    • @TopperMachineLLC
      @TopperMachineLLC  ปีที่แล้ว +1

      I tore it that thin. That is the nice part of emery cloth, you can rip it to whatever you need.

  • @bcbloc02
    @bcbloc02 ปีที่แล้ว

    If it goes undersized you don’t have a problem just your shop is too cold. Lmao😂

  • @riliwi
    @riliwi 7 หลายเดือนก่อน

    How do you reharden it ??

  • @johnmcanulty7341
    @johnmcanulty7341 ปีที่แล้ว

    Tense moment at the end: Hoping you were not going to have an accidental caliper/concrete collision.

  • @oldreliable303
    @oldreliable303 ปีที่แล้ว

    Where are you getting + or - .100 i was also told if it is a frackson it is + or - .015?

    • @TopperMachineLLC
      @TopperMachineLLC  ปีที่แล้ว

      It is on the drawing. Fractional was +/- 0.100. I have seen drawings with fractional being +/- 1/4". Pretty crazy how different engineers draw things.

    • @oldreliable303
      @oldreliable303 ปีที่แล้ว +2

      @@TopperMachineLLC im use to a tool and die shop, + or - .005 is loose, .100? is, ill do that in the welding shop..

  • @oldmetalmachines2094
    @oldmetalmachines2094 ปีที่แล้ว

    Well when you have a big Johnson you need a big caliper! Lol. Great video

  • @donmedford2563
    @donmedford2563 ปีที่แล้ว

    @5:20. Yea I know what you mean. I am undersized when I am cool too. lol

  • @schism47
    @schism47 ปีที่แล้ว

    Man Josh I am jealous of the 50 inch vernier caliper. Can I have it? Haha

    • @TopperMachineLLC
      @TopperMachineLLC  ปีที่แล้ว

      Lol, NO! They are serious money. But worth every penny

    • @schism47
      @schism47 ปีที่แล้ว

      @TopperMachineLLC haha. I know they are. Definitely worth the money too.

  • @ttnd3d_387
    @ttnd3d_387 ปีที่แล้ว +1

    In a ball screw, the main diameter is where the balls roll. Outer diameter as after production. Not accurate for use as a base.

    • @RJMachine62
      @RJMachine62 ปีที่แล้ว +2

      The O.D. of "Rolled" ball screws can vary a lot from the pitch diameter/where the balls touch and I typically make a brass or aluminum spilt bushing and use a 4 jaw then test indicator to dial in the ball groove. On ground ball screws, most of the ones I've checked are very close and I'll just use a collet like Josh did. Annealing helps tremendously!

  • @markshort9098
    @markshort9098 ปีที่แล้ว

    +/- 0.100 is more than likely a misprint, it was probably supposed to be +/- 0.001

    • @TopperMachineLLC
      @TopperMachineLLC  ปีที่แล้ว

      No it was correct. It's one of the largest fractional tolerances I've seen, but it was correct

  • @brucherrin8947
    @brucherrin8947 ปีที่แล้ว

    🍒

  • @rerun578
    @rerun578 ปีที่แล้ว

    Best price on a Starrett 123-50: about $5K. Heh heh.

    • @TopperMachineLLC
      @TopperMachineLLC  ปีที่แล้ว

      they aren't cheap! Better have an absolute need for one before buying it.

  • @TalRohan
    @TalRohan ปีที่แล้ว

    there is something so odd about having a tiny cutter like that in a massive lathe like that...very out of place lol

  • @clutch5sp989
    @clutch5sp989 ปีที่แล้ว +2

    While Josh does the work live, the customer is screaming, "WAIT WAIT STOP STOP...NEED TO MAKE A CHANGE". Also, we CAD guys don't mix our dimension styles fraction & decimal as shown on the print. Arrg...wanted to rip my testical off with such drawing blasphemy !

    • @TopperMachineLLC
      @TopperMachineLLC  ปีที่แล้ว +4

      I have seen so many drawings over the years like this. It is funny how if you add up all of the tolerances, you can really screw up a part. I learned this years back at shop I worked in. Sure, the part was within tolerance, but the assembly it went into would not work. I spent a couple days with engineering to correct all future problems with their parts.

  • @orville697
    @orville697 ปีที่แล้ว

    metric is far easier 🙂🙂🙂🙂🙂

    • @TopperMachineLLC
      @TopperMachineLLC  ปีที่แล้ว +1

      I don't measure in Deer Turds. I prefer Bananas

    • @orville697
      @orville697 ปีที่แล้ว

      @@TopperMachineLLC the rest of the world begs to differ only 3 countries still use imperial 😂😂😂😂😂😂😂😂

    • @TopperMachineLLC
      @TopperMachineLLC  ปีที่แล้ว

      @@orville697 If the rest of the world jumped off a bridge????? Being different is not a bad thing!

  • @levitated-pit
    @levitated-pit ปีที่แล้ว

    it shrank 4 tenths !!! is that of an inch? dude you gotta go metric

    • @TopperMachineLLC
      @TopperMachineLLC  ปีที่แล้ว +5

      Metric hardly ever comes in this shop. It is an inferior measuring system.

    • @levitated-pit
      @levitated-pit ปีที่แล้ว

      you are a heathen,, a denier of truths may your god lead you to idiocy while my science leads me to accuracy! (chuckle ... i still use thous to describe a small measurement. im 62 yrs old, UK born n bred, been carving metal since i was 14 !!! metric is just better.@@TopperMachineLLC

    • @kennethstaszak9990
      @kennethstaszak9990 ปีที่แล้ว +2

      @@TopperMachineLLC My momma taught me at a young age - just because others do something doesn't mean you have to do it too. Metric system evangelists need to remember this important lesson.

    • @ellieprice363
      @ellieprice363 ปีที่แล้ว +2

      Why? His whole shop, like mine, is full of Imperial tools that measure in inches, thousands, and ten thousands of inches. Both systems are highly accurate, just different.

    • @dcraft1234
      @dcraft1234 ปีที่แล้ว +1

      If only we had some kind of tools to tell us what 4 tenths of an inch is...hmmm what could we use?