Taming the bark of an Avenger

[TorqueMaster]

what settings people prefer to print threads here?

Being well tuned -- not over or under extruding helps.
 
I print most of my threads with the shaft (or hole) standing up -- vertically.  This gives clean threads, created without overhangs or supports.  Printing this way -- in the Z axis -- is weaker than printing in the XY, so layer adhesion is very important to get a strong part.  I did some tensile testing to find the best temperature for my filament, at different layer heights as well.  Hotter/meltier does not always give a stronger layer adhesion.  I don't have my notes here, but I believe thicker layers were stronger when printed about 5C hotter than thin layers (or vice-versa.)

Layer height used is dependent on the thread pitch.  I've been doing lots of metric x1.0mm threads, and they do best at 0.16mm layers or lower.  That's roughly 6 layers per tooth, minimum.  I have been using CURA's adaptive layers, to print threads at 0.16 and the rest of the part a bit thicker.  That setting doesn't give as much control over layer heights as I'd like, but it does work, and the results look good. 

Regarding CURA adaptive layers...on the Ender 3, and probably other fdm printers, the Z-axis stepper motors have the most torque at certain layer heights that don't require the stepper to use "micro-stepping."  More torque means less likelihood of a layer height change missing the exact height requested.  So on the Ender 3, I almost always use layers divisible by 0.04mm to avoid micro-stepping.  0.12, 0.16, 0.20, 0.24mm, etc.  When using adaptive layers in CURA, I set it up to use those layers heights only, to best ensure consistent, strong layer adhesion, despite the changes in layer height throughout the part.

Not a bad idea to chase external threads with a die, but often it's not necessary.

Internal threads, printed in the Z-axis, suffer the same shrinkage as holes printed in the Z-axis.  When I experimented with printing nuts and bolts at published dimensions, the printed bolts were usually very close to - if not perfect fit for off the shelf hardware.  The printed nuts, were almost always too small.  CURA has a setting for hole expansion which may work to fix this, I've not tried it.  I increase hole/thread size in my designs to compensate.  Through experience/guestimate/trial and error.  The diameter error is usually 1 nozzle width or less.  Smaller holes are more affected than larger holes.  Printing the part with thick enough walls, for strength, is a good idea, and tapping (or drilling/tapping) the too small threads is an option, too.

I think that's the nuts and bolts of it, lol.  I'm open to answer any more specific questions.

[Baco]

what settings people prefer to print threads here?

Being well tuned -- not over or under extruding helps.
 
I print most of my threads with the shaft (or hole) standing up -- vertically.  This gives clean threads, created without overhangs or supports.  Printing this way -- in the Z axis -- is weaker than printing in the XY, so layer adhesion is very important to get a strong part.  I did some tensile testing to find the best temperature for my filament, at different layer heights as well.  Hotter/meltier does not always give a stronger layer adhesion.  I don't have my notes here, but I believe thicker layers were stronger when printed about 5C hotter than thin layers (or vice-versa.)

Layer height used is dependent on the thread pitch.  I've been doing lots of metric x1.0mm threads, and they do best at 0.16mm layers or lower.  That's roughly 6 layers per tooth, minimum.  I have been using CURA's adaptive layers, to print threads at 0.16 and the rest of the part a bit thicker.  That setting doesn't give as much control over layer heights as I'd like, but it does work, and the results look good. 

Regarding CURA adaptive layers...on the Ender 3, and probably other fdm printers, the Z-axis stepper motors have the most torque at certain layer heights that don't require the stepper to use "micro-stepping."  More torque means less likelihood of a layer height change missing the exact height requested.  So on the Ender 3, I almost always use layers divisible by 0.04mm to avoid micro-stepping.  0.12, 0.16, 0.20, 0.24mm, etc.  When using adaptive layers in CURA, I set it up to use those layers heights only, to best ensure consistent, strong layer adhesion, despite the changes in layer height throughout the part.

Not a bad idea to chase external threads with a die, but often it's not necessary.

Internal threads, printed in the Z-axis, suffer the same shrinkage as holes printed in the Z-axis.  When I experimented with printing nuts and bolts at published dimensions, the printed bolts were usually very close to - if not perfect fit for off the shelf hardware.  The printed nuts, were almost always too small.  CURA has a setting for hole expansion which may work to fix this, I've not tried it.  I increase hole/thread size in my designs to compensate.  Through experience/guestimate/trial and error.  The diameter error is usually 1 nozzle width or less.  Smaller holes are more affected than larger holes.  Printing the part with thick enough walls, for strength, is a good idea, and tapping (or drilling/tapping) the too small threads is an option, too.

I think that's the nuts and bolts of it, lol.  I'm open to answer any more specific questions.

that's a good summary, thanks sir

as you brought up tensile strength i recall there's something about the layer height to nozzle width ratio in that using a bigger nozzle allows bigger LH's but the curve flattens about 1:3 ratio, can't find the graph rn

also random seam placement is better right?

the setting tolerance:inclusive/middle/exclusive in Cura or x/y compensation in prusa should help with the inner threads issue i think

[TorqueMaster]

that's a good summary, thanks sir

as you brought up tensile strength i recall there's something about the layer height to nozzle width ratio in that using a bigger nozzle allows bigger LH's but the curve flattens about 1:3 ratio, can't find the graph rn

also random seam placement is better right?

the setting tolerance:inclusive/middle/exclusive in Cura or x/y compensation in prusa should help with the inner threads issue i think

Yes, about the LH:N ratio, I've seen some graphs where thinner layers were always stronger, others where there was an optimum.  Layer adhesion is as much about getting the right temperature for that ratio -- but yeah, as a rule of thumb I stay with layer height between 50% and 25% of nozzle width.

Random should be better, if there are no cosmetic issues to worry about.

I think it's exclusive that will slightly increase the hole size -- and affect all other dimensions, too.  Not the right way to fix it.

[Bluesman]

I have Subscriber's plume design on my Notos and his Notos-inspired design on another rifle. Now I just won Angie's custom Avenger from the GTA contest and I'm hunting for Avenger options.  Thanks GTA, this is going to be fun!

Has there been a +2" .25 cal plume and/or a .25 Shorty? The Avenger is already fairly long on it's own.

[subscriber]

Dino, there have been so many variants I can't remember them all.  I think I did some shorter .25 versions for forum user TorqueMaster (Bob). 

I just checked my email to Bob, and found relevant designs I sent him on 23 March this year.

The forum is not accepting even a zipped file for being too large, so I am posting a link to wetransfer that will be active only for 7 days from now: 
You can download both STLs from here: https://we.tl/t-n39cOo7vGo

[Bluesman]

Thank you, those both look great. Already downloaded and will be printing at least one tonight!

It's unfortunate the forum is limiting file size so much, your great work is not so readily available. I have no personal experience with file sharing sites but I see mediafire being used often and it doesn't have the 7 day expiration restriction. Maybe it's a better choice for you.

[Back_Roads]

 Congratulations on winning the GTA avenger Dino ! 

[nervoustrigger]

Avenger Shorty +2"

Subscriber, I just wanted to thank you for your time and talents and graciousness to design and post these designs for us to enjoy.  Last night I printed the "shorty +2in" and installed it this morning, and I would say it knocked the report down by a good 75%.  Totally transformed the character of shooting the gun to be honest.

[subscriber]

Thanks for the feedback, Jason.

 

[Spin]

Avenger Shorty +2"

Subscriber, I just wanted to thank you for your time and talents and graciousness to design and post these designs for us to enjoy.  Last night I printed the "shorty +2in" and installed it this morning, and I would say it knocked the report down by a good 75%.  Totally transformed the character of shooting the gun to be honest.

Ditto, You guys worked out one of the  Plus 2"    * .25 Avenger Shorty Pluss 2."  in .22 cal and it worked out beautifully. I couldn't be happier with it.
         Now I need one in .25 Cal for my .25 Avenger that I'm working on and plan to set up for Varmint shooting (slugs) IR night scope mounted.
         Who can I talk to about getting this second one made?

[subscriber]

Jerryy,

Are you asking for the Shorty plus 2 version with .25 in its name?

The CAD values for the baffle bore diameters are shown below.

The zipped print file is attached, so you can have anyone print it for you.  As TorqueMaster was part of the development of the Avenger LDCs, I suggest you ask him to print you one.

[JimD]

Thanks Peter, I may try one of these on my 25 Avenger. 

[subscriber]

You certainly may, Jim. 

Ask TM to print you one.

[TorqueMaster]

Plenty of filament on hand! 

Also don't forget the "full plume" with about 4" ahead of the shroud.  In my testing with a 22 Avenger it was significantly quieter than the shorty +2.  I keep one on my target shooter 177 Avenger all the time.

[Baco]

does anyone have the long version with checkered finish?

[subscriber]

does anyone have the long version with checkered finish?

Can you point to an image of the checkered finish?

By have, do you mean own the physical part, or the STL?

[Baco]

does anyone have the long version with checkered finish?

Can you point to an image of the checkered finish?

By have, do you mean own the physical part, or the STL?

attached is the image, recently i lost all the STL files i had on the pc
 if you have more avenger and generic ones handy please send me

[subscriber]

Baco,

I just sent you a test email using the address I had for you, to see if it still works.

If so, I will see if I can find the STL you are looking for, and send it to you.

[subscriber]

By the way, Baco, some of the latest Avenger STLs are attached to recent posts in this thread.  Such as for the smooth version of the latest 4" extended Avenger insert you showed next to the cross-ribbed one:
https://www.gatewaytoairguns.org/GTA/index.php?action=dlattach;topic=196584.0;attach=437737

I will look at other files I emailed you, and resend those.

[kbstingwing]

I just downloaded a Moderator baffle from thingyverse, I modified it to work with a .25 cal, made the hole 8mm, it works fine, printed 4, 2 for me and 2 to send to my friend for his Avengers.