Technical name for brass olive  

RE: Technical name for brass olive

Posted by: @iamnot414

The tube from the extruder to the hotend keeps popping out of the fittings. Once on the end with the extruder and twice from the end with the hotend.  I can't seem to reuse the "brass olives", as described from ( https://help.prusa3d.com/en/guide/how-to-replace-a-bowden-ptfe-tube-mini_142572) Step 4.  I have some replacement tube but I know the technical name of the parts to order some more.  I can re-use the brass nut but can't get the olives to go over the tube.  I don't see where I can order just the "olive" parts in the Prusa shop either.  Also, what would be the size? Please help!

Thanks,

Michael S.

I ordered this fittings here: https://www.aliexpress.com/item/32946052979.html?spm=a2g0s.9042311.0.0.76aa4c4dmgoLOc

RE: Technical name for brass olive

@karl-herbert

Thanks for the link.  I am assuming you got the 4mm size.  How was shipping?  It currently is listed at 30-50 days. I can't justify sending $35 on shipping when the part is less than $1.

RE: Technical name for brass olive

These compression fittings are very common, they are used in air con for example. There should be a number of local suppliers, there's no need to go to China. If I search ebay, I find 431 hits, delivery in a few days. The technical name is "4mm brass compression olive" 🙂

RE: Technical name for brass olive

@iamnot414

$35 for shipping is intense!I didn't pay for shipping. The delivery takes 3 weeks, but I ordered them only on reserve. In your case I would also look for a local supplier. The Mini fittings have this design:

4mm brass compression olive for the Prusa Mini

RE: Technical name for brass olive

@iamnot414

As @bobcousins mentioned they're compression fittings, similar to ferrules uses in Swagelok (or Eaton) tube fittings for air and gas service. 

A couple months I was also curious if I could purchase them separately. After asking Prusa Support about purchasing them and getting the unfortunate reply that they don't sell them, I ended up finding these on Ebay: https://www.ebay.com/itm/10-Pack-Lot-4mm-Tube-Ferrule-Brass-Compression-Sleeve-Ring-Fittings-Coyote-Gear/222107931567?hash=item33b6aa13af:g:tsYAAOSwd3dZaA4~

They were $17.88 (w/shipping) for 10 of them when I bought them so not necessarily the cheapest thing but they do seem to be compatible.

The invoice they sent mentioned they have cheaper prices on their website but I didn't check into that to verify. 

Below is a picture comparing the Coyote Gear and Prusa fitting (note the Prusa fitting is crimped). 

RE: Technical name for brass olive

Hi!  I'm not saying you should, but I just successfully reused one by expanding the squeezed end with a small pair of pliers, just pushing down a few times until it's enough expanded. Then I made sure to turn it so that it's the fresh end got crimped this time as I don't trust the reused part, you can tell it's been used, but since it's got two sides I figured why not? 😇 

RE: Technical name for brass olive

is there a special tool to crimp these?

RE: Technical name for brass olive

Posted by: @christian-4

Hi!  I'm not saying you should, but I just successfully reused one by expanding the squeezed end with a small pair of pliers, just pushing down a few times until it's enough expanded. Then I made sure to turn it so that it's the fresh end got crimped this time as I don't trust the reused part, you can tell it's been used, but since it's got two sides I figured why not? 😇 

Nice little hack to be able to reuse the brass ferrules.. Saves waiting 2 - 3 weeks for new ones.. Its a pitty they are so hard to find.. and Prusa only sells a complete kit.. 

RE: Technical name for brass olive

@steve-smith

These compression fittings are more suited for high pressure applications. The problem with using PTFE tubes is that the inner diameter is reduced by too high compression and this can result in filament transport problems. If the compression is too low, the PTFE's can become loose, which happened to me several times.

For this reason I decided to use the PC4-M8x1.25 connectors, which are working fine without any issues.

RE: Technical name for brass olive

Posted by: @karl-herbert

@steve-smith

These compression fittings are more suited for high pressure applications. The problem with using PTFE tubes is that the inner diameter is reduced by too high compression and this can result in filament transport problems. If the compression is too low, the PTFE's can become loose, which happened to me several times.

For this reason I decided to use the PC4-M8x1.25 connectors, which are working fine without any issues.

It's recommended to keep (the solid end) of a 2 mm drill inside the tube when squeezing it to avoid this. ..which I missed at one point but then I just just carefully used the drill end of the bit to clear out the passage in the tube by hand, worked fine. 

RE: Technical name for brass olive

Posted by: @karl-herbert

@steve-smith

These compression fittings are more suited for high pressure applications. The problem with using PTFE tubes is that the inner diameter is reduced by too high compression and this can result in filament transport problems. If the compression is too low, the PTFE's can become loose, which happened to me several times.

For this reason I decided to use the PC4-M8x1.25 connectors, which are working fine without any issues.

It's recommended to keep (the solid end) of a 2 mm drill inside the tube when squeezing it to avoid this. ..which I missed at one point but then I just just carefully used the drill end of the bit to clear out the passage in the tube by hand, worked fine. 

Oh and I also had the other problem, being too loose but that was because I tried to re-attach it to the same spot. I needed to cut the end a bit of the tube so it's fresh. 

Then again, when the pressure was so high for it to pop in the first place, there was problem with the hotend causing jams, I guess that kind of pressure shouldn't really happen. Still, I too think about getting PC4-M8x1.25 connectors too though if this happens again later.

RE: Technical name for brass olive

@christian-bjorklund

Is of course a possibility, but I still like the PC4 more. On the Mini the cuts on the PTFE tube are not as drastic as on the MK3, because there is less rotation on the PC4 connection. Furthermore you don't have to replace or edit anything when removing the tube (brass olive).

RE: Technical name for brass olive

@karl-herbert

Can you post that link again?  I might try the PC4s. 

RE: Technical name for brass olive

@cwbullet

I have ordered this one: https://de.aliexpress.com/item/32967678995.html?spm=a2g0s.9042311.0.0.27424c4d3jpjAX

(PC4-M8)

Found on MSC Direct

I just found a US source for these: https://www.mscdirect.com/product/details/03751815

RE: RS

Might be cheaper from here ($0.237 each + $10 DHL to USA) https://export.rsdelivers.com/product/legris/0124-04-00/legris-brass-compression-olive-4mm/2936721

If anyone wants to split a bag with me, pretty sure you could send these domestically in an envelope.

RE: Technical name for brass olive

In case someone would need a supplier in the Czech Republic (or around), I bought those "olives" here and they fit and work well: https://www.kovaz.cz/mosaz-prstynek-sroubeni-pro-pneumatiku-4mm-0124-04-00-134754/

RE: Technical name for brass olive

here the link from Aliexpress reprap official store. i don't know it's legit or not, but from reviewers photo it looks real.

RE:

Thank you christian-4

Thanks for the post, it put me on the right path. I ended up using a finishing nail punch to stretch the olives.  Put it on soft wood and give it a few taps with a small hammer until it fits.