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Longer hobbed bolt upgrade.

Discussion in 'Mods and Upgrades' started by BrooklynBay, Jun 15, 2018.

  1. BrooklynBay

    BrooklynBay Active Member

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    The R1 uses a 50MM long hobbed bolt. I need a 60MM or 65MM long hobbed bolt for this: https://www.thingiverse.com/thing:2789217. I purchased this bolt on EBay: https://www.ebay.com/itm/182447194250 but the teeth don't grab the filament that well. The prints have gaps, poor layer adhesion, and are brittle. The filament feels very loose so I know that this cheap hobbed bolt isn't grabbing it. I have three choices for an upgraded bolt but I don't know which one is the best.

    1. https://www.ebay.com/itm/331401657656
    2. https://www.ebay.com/itm/262458252361
    3. https://www.filastruder.com/collect...ies/products/hobb-goblin-8mm-hobbed-shaft-kit
     
  2. daniel871

    daniel871 Well-Known Member

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    The Hobb-Goblin is generally considered the better one, as it's another E3D product.
     
  3. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    1 or 3 is probably the best for you. The fine-grained teeth in the one you bought require more pressure from the extruder feed and you probably would need to slow down. Fine if you want a details type printer, not if you want to print faster. Use one with coarser teeth.
     
  4. BrooklynBay

    BrooklynBay Active Member

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    Thanks for your reply. I found the link for the Hobb-Goblin hobbed bolt in another thread on this site. Mike Kelly recommended it to another member. It's similar to the brass version on EBay, but it's stainless steel, and the groove doesn't appear to be as deep. Stainless steel is stronger than brass, and should last longer while working with abrasive filaments.
     
  5. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    There is so little friction it probably isn't a big deal, but I do use steel bolts myself.
     
  6. BrooklynBay

    BrooklynBay Active Member

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    The original one that I bought was plain black iron. The first one appears to be either stainless steel or some sort of zinc coated iron. Which brand do you use? I saw Youtube videos about making a regular bolt into a hobbed bolt. I didn't print a jig for it so it didn't come out right when I tried to do it free hand.
     
  7. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    I just bought mine from a couple of eBay sellers that had them for the Robo. Each one had a different hobbed pattern. Like $5 a pop.
     
  8. BrooklynBay

    BrooklynBay Active Member

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    How long do they usually last until they wear out? I guess it probably depends upon the type of filament being used. I usually use PLA & TPU which aren't that abrasive compared to metallic filaments which I use occasionally.
     
  9. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    Mine have been running for years without issues and many hundreds of kg's of filament. The finer teeth would tend to wear out faster I imagine.
     
  10. BrooklynBay

    BrooklynBay Active Member

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    I saw somebody on EBay selling a belt driven assembly. I would assume that direct drive or gears would be better than a belt since belts stretch & break. Are herring bone gears any better than the stock plain gears?
     
  11. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    The timing belts used are not going to stretch much (and shorter ones less so) but sure, belts can possibly stretch over time. There may be some minor improvements with the herringbone gears (I have not seen any, but YMMV)

    Make sure you adjust the firmware if you do anything that affects the gear ratio. Calibrate the extruder at a minimum
     
  12. BrooklynBay

    BrooklynBay Active Member

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  13. BrooklynBay

    BrooklynBay Active Member

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  14. BrooklynBay

    BrooklynBay Active Member

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    I've narrowed this down to two choices:

    1.https://www.ebay.com/itm/132329311837?var=431655022892

    2. https://www.ebay.com/itm/Hobbed-bol...6?hash=item4d2913fd38:g:e64AAOSw5dNWl~AL#rwid

    The first choice comes with the mounting hardware, is specified as 25MM for the hob, and made for 1.75MM filament. It might take a month to order as the downside.

    The second choice doesn't list the specifications, but another listing for the same seller has feedback saying that it's 26MM for the hob so I would have to use a washer as a spacer which is no big deal. It doesn't say if it's for 1.75MM filament but it looks like the groove isn't deep. The seller has another listing with all of the hardware for a little more but I don't think that I need the hardware anyway since I have it from the stock bolt. The seller is in the USA so it could take a week to deliver which is a plus.

    Both bolts appear to be steel but I doubt that it's stainless steel.
     
  15. BrooklynBay

    BrooklynBay Active Member

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  16. BrooklynBay

    BrooklynBay Active Member

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    I bought this bolt: https://www.ebay.com/itm/132329311837?var=431655022892. Compared to the unfinished black iron bolt from China, this bolt has more grip but it still has a small percentage of slippage. Do you think that the adjustable E3D bolt or that brass adjustable bolt from EBay will grip better or the same as this bolt? This steel bolt fit very well, and didn't require washers to shim it into place. I was able to get a smooth print out of it with better layer adhesion but the layer still has some small gaps in several areas. Maybe it's just the quality of the filament, and not the bolt?
     
  17. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    Not the bolt :)
    Make sure you calibrate the extruder and it is fine.

     
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  18. BrooklynBay

    BrooklynBay Active Member

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    I think that I might have figured out why the filament slips. The R1 came with a soft spring, and a firm spring on the bolts to tighten the tension. I was able to pull out the filament even though the bolts were fully tightened. This shouldn't happen. I put the stiff spring on the left, and the soft spring on the right, then tightened the bolts, and the filament felt snug. The filament wasn't able to be pulled out easily since it had tension against it. It seems okay for now but I think that it should have two springs with firm tension. I don't know if the R1 came with these type of springs or the previous owner put them in.
     
  19. Geof

    Geof Volunteer Moderator
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    previous owner. Both springs are the same on a new unit. Put some washers in front of the springs and tighten down. For most materials you really cant have to much tension with the greg wade set up.
     
  20. BrooklynBay

    BrooklynBay Active Member

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    I did a test print since I moved the springs, and it came out great! There are small washers on the screws, but they tend to get caught on the springs. I saw a good deal for 10 new stainless steel springs on EBay for 99 cents with free shipping, so I want to see how it prints when both springs have the same tension. It's possible that the previous owner lost one of the springs, and replaced it with a mismatched spring. This is probably the reason why my prints would sometimes come out fine then at other times it looked terrible.
     
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