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Kent Trammell (theluthier)

23 replies · posted

Backhoe Contribution - theluthier - Digger Arm & Cab Frame

This is a thread dedicated to the digger arm and cab frame parts of the backhoe project. Hardsurface modeling awesomeness 🤘

  • Don't worry Kent. I'll keep your thread alive while you are on vacay!

    • The Bucket on your Backhoe has normals inverted just FYI.

      Super easy fix but I thought I would let you know if you didn't notice already. (image below has back-face culling active).

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      Thanks for resuscitating my lifeless thread blanchsb 😆

      It's a good time to be notified about the bucket normals. I finally started fleshing it out recently:

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      Progress Update! I think I'm finished with the main pieces of the digger arm. Now I just need to do a final pass of the finest details (hydraulic lines, brackets, and double-checking for rivets/screws/bolts)

      The bucket's teeth took longer than I like to admit 😅

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    Hydraulic lines have proven to be a fun, tedious, but rewarding process. Then I unhid the plate that covers most of it...

    • Just think of how Adrian will feel when we cover the engine Lol

    • If I don't bolt it down properly it will fall out the bottom for everyone to see. 

    • Or you could do it like Tommy Boy way and leave the oil can in so that the hood pops at the most opportune time during the demo reel!

    • theluthier  I just had this thought while I was modeling my hydraulic lines.........is our current full model "true to scale"??? Because when I made a comment to use 3/4" lines in the live stream I believe that will only work if the rest of the DOG is 1:1 scale.
      I figured I would ask what the scale is before I go to town on all of my hydraulics.

      If it is not 1:1 that is no biggie but knowing what the current scale is: I could back-calculate the "scaled diameter" of 3/4 inch lines

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      As far as I know our DOG is 1:1 scale. spikeyxxx pointed out last month that our scale was slightly off to which I corrected in the 3rd iteration of the master file.

      However I too was thrown off by the actual scale of the hydraulic lines as I modeled, especially when I found this video:

      Which is a zoomed in shot of this part:

      The fitting is way bigger than I estimated perceptually. However whenever I threw in a 6-foot human mannequin and placed his hand in the same spot, it didn't feel that far off:

      For the black lines (which seem thicker in photos) I've gone with 3/4" diameter and for the metallic lines I've gone with 1/2". What do you think blanchsb?

    • That's funny I did the same thing. Black lines 3/4" and metal lines 1/2"

      It's like we are sharing the same brain waves!!!

      I wonder if those "larger than life" connection points are for ease of connection for operators?

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      No way! Haha that's awesome 🤜💥🤛

      I wonder if those "larger than life" connection points are for ease of connection for operators?

      Good question. It really put the scale of the backhoe into perspective for me. The thing is a hossAnd the fact that the guy hand-tightened that massive fitting kinda blew my mind too.

    • Yeah, I just realized you posted the video link. Yeah that is a specialized fitting for ease of installation. It looks like it has an O-ring for making a good seal and it is larger so that it can easily be turned and installed by hand. Larger diameter fittings are easier to fasten since you have more circumferential area to make a larger "moment-arm" to transmit your force. Now I am getting into engineering terms haha.

      Think of it like trying to pry up a heavy rock by your hand, then you grab a long and strong stick and use that to pry the rock. The long stick makes it easier because you get a long moment arm that takes most of the stress with little force from the user.

      If those fittings were smaller they would be harder to tighten by hand. And then the operator would have to carry a tool box/wrenches with him everywhere he goes (who wants to do that?!?)

      I like how they design those accessories for ease of use. That is really the "wow" factor that promotes a great user experience.

    • Could you please send me a copy of your file so I can verify my tubing sizes? Or I can send you mine. Either way.

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      Dude, super interesting. Makes total sense. Just when I start to marvel at our efforts to recreate a shell of this thing, the reality sets in that people designed every part inside and out. Bad. Ass.

    • Based on the size of the black hydraulic hoses to that dude's fingers I am glad I said 3/4" for those black lines. They definitely look roughly 3/4" (if not slightly larger).

    • Again unfortunately for adrian2301 he doesn't have many "larger than life" fittings for the engine, ..........so wrenches and hand tools all the way. I know a guy at Cornwell tools and will cut you a deal.


      Looks like those special hand-tighten fittings are going to be for the digger and accessories parts.

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    Haven't updated my thread in a long time. Last week I spent several hours adding many details to the cab frame:

     There's so many little bits and pieces I never noticed: Latches, handles, hinges, etc. All of which are made awkward by the subtle rounded contours of the frame and windows. Still only 75% done by my estimation.

    rryzen7 and ketre you have my continued sympathy for the complexity of this part! 😵

  • Your cab looks awesome theluthier  I just want you to know I think you are my favorite teacher ever except for my 1st grade teacher.  I love that you teach when, why and how.  Give us the opportunity to make the attempt. But more than that when we attempt you tell us what's wrong and show us how to correct.  You say it to us in a way that doesn't hurt nor sound critical, and you are sincere. 

    To all the others involved I can say with honesty that after my first attempt at the cab I knew I was way out of my comfort zone. Yet I felt encouraged by you and the others to keep trying. For this I will always be grateful.  I have truly learned so much by participating.

    I'm ready to try something else tho...continue studying and learning what I set out to do.  Trust me when I say I'm not discouraged by this at all. When Kent said he's going to use his cab I felt such relief...haha

    The outcome of this project has so impressed me with what you guys have done!

    • Well said ketre , I second that.

      I also have admiration for you ketre , for your determination and continued improvement. You have made great progress. 👍

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      ketre I'm so humbled by your comments. I've already added this to my mental rainy-day filing cabinet. Truly it means a lot! Thank you 🙇‍♂️

      In turn I second adrian2301 in admiring you. It takes a strong student mindset to try something outside one's comfort zone, receive and digest constructive criticism about that thing, and continue forward undeterred. You can't help but be successful with that mentality.

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    I'm relieved to announce that I'm finished with the cab, exterior and interior! I wasn't sure I'd ever finish all the little bits. To my liking I should say...It's not 100% perfect or comprehensive but I'm satisfied enough.

    There is one key piece of the interior missing: The floor mat. I need to do that last since it depends on all other interior parts to be finished.