make shrink-on sleeve

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jferguson
Posts: 247
Joined: Mon Mar 30, 2015 7:26 pm
Location: St Petersburg, FL

make shrink-on sleeve

Post by jferguson » Tue Jan 25, 2022 7:07 pm

Nikon could have thought more about the design of their 500MM F8 Catadioptric lens. As it is, it is impossible to hand-hold without disturbing the focus which on a lens of that focal length is very twitchy.

So I made this aluminum sleeve for mine and it works exactly as I had hoped. I support the lens and camera right hand on camera left hand under the aluminum tube and focus with my left hand finger tips. I take a lot of shots and use a Sony A-7II which has motion suppression.

I had planned to paint the aluminum tube black using DuraCoat applied with my airbrush. This paint is very popular in the firearms community which made me think it would be plenty good for this application.

Then it occurred to me that I could print a black PETG sleeve using vase mode. So finally, here is the question. Do you think I can find a diameter to print the sleeve that will let me shrink it onto the tube? My plan would be to make it a bit smaller than the tube, then heat it up in hot water and hope that I can get it over the tube and that when it cools it will shrink for good fit.
nikon500f8.jpg
pre-paint.jpg
rear-grip.jpg

Phil
Posts: 214
Joined: Mon Sep 19, 2016 7:49 pm

Re: make shrink-on sleeve

Post by Phil » Tue Jan 25, 2022 9:06 pm

I do not know how well 3-D printed plastics obey all these particular laws, but if this page is applicable,https://dielectricmfg.com/knowledge-base/petg/,
then a 4" dia. tube will be roughly 0.02" larger in diameter at 50ºC higher temperature.

jferguson
Posts: 247
Joined: Mon Mar 30, 2015 7:26 pm
Location: St Petersburg, FL

Re: make shrink-on sleeve

Post by jferguson » Tue Jan 25, 2022 9:47 pm

Thanks Phil,
Coefficient of expansion ought to at least suggest a place to start.
i'll make a few rings maybe an inch long of slightly different diameters, try them and use the size that works for the big one.

thanks again.

airscapes
Posts: 594
Joined: Wed Jan 31, 2018 11:36 pm

Re: make shrink-on sleeve

Post by airscapes » Wed Jan 26, 2022 2:28 am

I think a much better option would be to print black Nijaflex in spiral mode and work it over the tube. I did the exact same thing to make an ABS tube less slipprey when working out a way to cover the focus ring of a usb microsocpe. I used the .35 nozzle with a solid modle and vase mode . I also have a gravity feed bearing spool holder and the extruder housing from thingyvers that was tightned up for the nijaflex.

PETG is not going to shrink, or expand, it is very heat stable in my experience. With a lot of tial and error you can get a good interferance fit, I made adapters for a 6" exhaust fan using PETG and spiral mode, no clamp needed. The purpose of the adapter is to catch condensate as the fan is in a non conditioned attic.
Good luck!
pluggable first try.jpg
fan sleeve 1.jpg
fan sleeve 2.jpg

jferguson
Posts: 247
Joined: Mon Mar 30, 2015 7:26 pm
Location: St Petersburg, FL

Re: make shrink-on sleeve

Post by jferguson » Wed Jan 26, 2022 2:50 am

I hadn't thought of ninjaflex but will give it some thought. coefficient of expansion tends to be pretty stubborn. I need to see if I get the same number Phil did and if this actually works with a real print, but .020 would be plenty good if I can get a sleeve that's at 50 or 60C above ambient shoved onto the tube before it cools down too far.

do you think I can print ninjaflex with a straight M2-E? I have the wham-bam magnetic print bed which I love. It's pretty much removed the aggravation of getting prints off the kapton and replacing the kapton tape even though I eventually got pretty good at it.

thanks for your suggestion.

airscapes
Posts: 594
Joined: Wed Jan 31, 2018 11:36 pm

Re: make shrink-on sleeve

Post by airscapes » Wed Jan 26, 2022 2:58 am

The bed is not the issue, the extruder housing is.. the filament it is too strechy.. royal pain butt till I printed that housing someone doctored up so there is not so much slop inside it is much more tpu freindly.
I think you can use PETG and get an abient temp interferenace fit that will slide on and be plenty thight for the use case. it isn't like you are pressing a bearing sleeve or something just has to be snug to look nice and not move. Don't over think this.. but you may want to use a .5 or .75 nozzle.
Give it a go with 1" test sleeves

jferguson
Posts: 247
Joined: Mon Mar 30, 2015 7:26 pm
Location: St Petersburg, FL

Re: make shrink-on sleeve

Post by jferguson » Wed Jan 26, 2022 4:13 am

there's always glue, or using windex as a lubricant same as floating kapton tape onto the bed glass.

I overthink everything.

airscapes
Posts: 594
Joined: Wed Jan 31, 2018 11:36 pm

Re: make shrink-on sleeve

Post by airscapes » Wed Jan 26, 2022 4:08 pm

jferguson wrote:
Wed Jan 26, 2022 4:13 am

I overthink everything.
That is what makes us Great!

Gwhite
Posts: 372
Joined: Tue Jul 11, 2017 3:38 pm

Re: make shrink-on sleeve

Post by Gwhite » Wed Jan 26, 2022 5:29 pm

jferguson wrote:
Wed Jan 26, 2022 4:13 am
there's always glue, or using windex as a lubricant same as floating kapton tape onto the bed glass.

I overthink everything.
In the world of 3D printing, that's not entirely a bad thing. Otherwise, you'd never get nice prints. I've been doing this for almost 5 years, and all the hype about how people can just buy a printer, slap on a spool of filament & start making amazing, detailed widgets still isn't close to being a reality. If you aren't up for overthinking, analyzing & experimenting, it's still not ready for prime time.

The filaments available now are better, and the slicers have come a long way (although they are still far from perfect). On anything fussy (like a shrink fit sleeve), I end up doing a half dozen small test prints of critical features before I will run a long complex print. I just finished two different 11 hour prints of mechanical test fixtures, and they both came out perfect. I spent days double checking the fit of various features beforehand.

The times I get in trouble are when I "underthink" & try to skip a few steps...

jferguson
Posts: 247
Joined: Mon Mar 30, 2015 7:26 pm
Location: St Petersburg, FL

Re: make shrink-on sleeve

Post by jferguson » Wed Jan 26, 2022 8:58 pm

Bingo GWhite,
I spent my career designing stuff, buildings and factories. Buildings and factories are different from little things like I machine or print now. You have to get them right the first time, no ducts running though elevator shafts for example - yes, someone I worked with did that in 1966, but it was caught before it got to the field.

In 1988 when I got involved with what was then called rapid-prototyping either with cnc mill or SLA which we had to send out to get printed, I fell into bad habits and many projects were done by successive approximation because it was a lot easier to see what a design needed when you were holding an iteration which hadn't quote gotten there yet in your hand.

quick turnaround and relatively low cost of increments leads to sloppy thinking.

I need to work on this more.

thanks,
John

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