Question for any pneumatics experts - Page 1
Forum section: electronics / general

author: TerraHertz
author_rank: Super Contributor
timestamp: March 26, 2017, 01:17:26 am
content: I've never had to work on pneumatics gear before, but a current project involves quite a bit of it. And just about every other type of plumbing, sigh.Anyway, I'm trying to find a cheap (China) source of 6/4 mm nylon & copper tubing compression fit brass olives and the reinforcing 'spigot' (edit: corrected from 'double g' spelling error) tubes. Mysteriously, these things seem to be entirely missing on Aliexpress and ebay. Surely I'm just using the wrong search terms or something?The term 'spigot' for those little brass tubes seems weird. But that's what the guys at my local Pirtek shop (pipe fittings) insist they are called. Which makes about as much sense as the term 1/4" BSP-T for a common brass fitting thread, which is most definitely not 1/4" dia.Also the "-T" means tapered thread, and there is BSP-P (parallel) which looks almost the same but is not really compatible.Pic 1 shows stepped "olives" for compression fit tubing joints. I can find those on ebay (but not Aliexpress.)Also the little brass tubes, for when you want the joint to absolutely never leak. They are a tight fit inside the nylon tube, and prevent it from collapsing. People commonly omit them in joints, because the 6mm OD, 4mm ID black nylon 'air brake tubing' is pretty tough and generally doesn't need them. But if you want to be ABSOLUTELY sure...Those I cannot find at all on Aliexpress or ebay. And that's my question - are there *really* none, or am I just failing to search right? There are some smaller ones, that are used in modern bicycle hydraulic brakes. But no general 6/4mm pneumatics ones.Pic 2 is the two general types of connection. The top one (orange) is a 'push-fit'. They are neat, and can be released as easily as connected. Some steel barbs lock onto the plastic tube, and pressing the rear ring in makes the barbs release. Theoretically very convenient but sometimes they won't release, and then it's a world of pain.No problem with getting any number of the push-fit ones on Aliexpress.Oh, and Pic 3 shows two of the several different styles of olives.

author: Gregg
author_rank: Super Contributor
timestamp: March 26, 2017, 05:21:06 am
content: The ring part is called a ferrule and the inner tube is called a ferrule sleeve as far as I know. Each manufacturer has their own slightly different ones and it may be hard to match your existing ones by sourcing them in China. A Google search of tubing ferrules will give you a lot of pictures and possible synonyms for these.

author: Marc M.
author_rank: Regular Contributor
timestamp: March 26, 2017, 05:24:47 am
content: I spent 15 years in the semi-trailer repair business, 5 years assembling computer guided material handling equipment, and the past 11 years as a CNC machine center technician, all of which use a lot of pnuematics. One of my many hats in the trailer biz was ordering parts and generating billing. I have always heard/used the terms Nut, Insert, and Ferrule for the compression nut, support tube, and crimp ring respectively. I've used some push-lok fittings that were sized for either 1/4" or 6mm tubing so they're close in size. You might be able to get away with 6mm brass. 6mm is slightly larger than 1/4" so I'd try to warm up the end of the tubing to make it more compliant then shove the insert in. This should expand the OD slightly closer to 6mm. There ferrule should have enough range to seal it as long as it's not seeing high pressures.Nowadays I use push-lok's for air just about exclusively due to their ease of use. Another advantage is they don't require an insert which restricts the airflow slightly. I've only run into a couple that wouldn't release. In those cases I cut the tubing off flush and replaced the fitting because forcibly removing the tubing will destroy the locking ring inside. The most common failure mode I've run into is just the opposite, it won't hang onto it and the tube blows off, but these are still very few and far between.

author: janekm
author_rank: Unknown
timestamp: March 26, 2017, 06:31:32 am
content: The "push-lok" style is indeed much more common in China. You might have some more luck starting with the catalog of a Chinese / Taiwanese pneumatic component manufacturer and taking it from there. For example:http://www.shako.com.tw/accessories/11.htmWhat you're looking for is mostly sold as accessories to air cylinders etc so you may have more luck talking to a shop that sells those, they will be able to supply all the common accessories. And, assuming you need air cylinders / valves etc you will have more luck looking for what is widely available in China rather than what is common in the US, most likely. ISO standard cylinders are common. Most of the manufacturers seem to stick pretty close to Festo standards too, from what I can tell (but I'm no pneumatics export so take all this with a grain of salt...).

author: IanB
author_rank: Super Contributor
timestamp: March 26, 2017, 06:48:56 am
content: Quote from: TerraHertz on March 26, 2017, 01:17:26 amJust FYI, it is "spigot", not "spiggot". A spigot is a thin tubular part that fits inside another tube. Changing the spelling may help your searches if you have no luck with all the other suggestions given above.

author: TerraHertz
author_rank: Super Contributor
timestamp: March 26, 2017, 08:27:42 am
content: Quote from: IanB on March 26, 2017, 06:48:56 amHa, thanks. You're right, it's single g on the invoice for the ones I bought. Switching single and double letters is my most typical spelling mistake.Though, it seems I've been typing it with single g at least sometimes in searches, since trying it again now gets product lists I've seen before. Camera/flash mounting spigots, sigh...@evb149 Thanks for the links. Lots of informative pics, and the Swagelok catalog is very useful. Especially will be later, when I get to the part of the project that needs stainless microtubing.But, US manufacturers' stuff is almost entirely imperial, and the rest of the world (me too) prefer to stick to metric where possible.Btw, my experience with McMaster is they refuse to post overseas. I've yet to try getting stuff from them via an 'assisted purchase' US intermediary, but will try it someday.Thanks for all the other advice too.I should clarify - I've been buying small numbers of parts from a local store that's about 5 minutes drive from home. I'm lucky to live near an industrial area with quite a few useful distributors. There I can get any number of the compression sleeves (77c ea) and spigots (87c ea) but since I'm poor and yet like to buy in decent amounts of stock of things, I'm looking for an Aliexpress or ebay-China seller with the usual price ratio of about 1/10th of local prices. So I can buy enough to not have to keep driving to the shops for ones and twos. I hate that.For eg, a simple 1/4'' BSP Thread 120 PSI Pressure Relief Valve - Au$21 locally, or AU $2.49 (free shipping) from ebay-China.It's hard to believe such a simple thing isn't made in China for 2c each (or at all, apparently.)Incidentally, the immediate use is for argon (which is expensive) lines that will get a lot of flexing. Hence using the liner reinforcing spigots. But in general I just like overkill. So it never breaks or leaks.There are some pretty neat Aliexpress pneumatics stores. For eghttps://fsqd.aliexpress.com/store/511925?spm=2114.10010108.0.0.7FJmAb

author: SeanB
author_rank: Super Contributor
timestamp: March 26, 2017, 10:15:46 am
content: FYI the compression fittings are almost invariably going to be for an imperial size pipe, as the controlled thing there is inside diameter, while the push fittings are almost invariably going to be metric, with the controlled diameter being the outside. Almost interchangeable in a lot of cases with each other tube wise, but especially in 6mm the metric pipe will fit the compression fitting, but the opposite is not true, that 0.25mm is not going to work.The inserts you are looking for are easiest to get not in brass but in stainless steel, as they are cheaper, and the wall thickness of them is a lot thinner as well, so better flow. Stainless sleeves and brass ferrules/olives are perfect together, and you even get 6.25mm plastic olives as well, that are just as good in most applications.Get a cheap tubing cutter as well to go with them, it pays for itself in getting decent sealing, and in getting the olives on as well.

author: DTJ
author_rank: Super Contributor
timestamp: March 26, 2017, 10:57:26 am
content: Plenty of push-lok knock offs on Aliexpresshttps://www.aliexpress.com/wholesale?ltype=wholesale&d=y&origin=y&isViewCP=y&catId=0&initiative_id=SB_20170326025411&SearchText=fitting+6mm&blanktest=0&tc=afIf you're shopping for solenoids I got some of these last week. I have not plumbed them up yet but they look better than I expected and operate ok.http://www.ebay.com.au/itm/172511868369

author: TerraHertz
author_rank: Super Contributor
timestamp: March 26, 2017, 11:45:34 pm
content: Quote from: SeanB on March 26, 2017, 10:15:46 amYeah, my pile of scrounged fittings is a fine mix, mostly Imperial. I'd figured out the 1/4" vs 6mm not-quite match. Same as with screws: BA, UNF, BSW, metric, etc. There are some very close but not-good matches to watch out for.QuotePirtek has the stainless ones, but even more expensive than the brass. Knew about the larger dia hole, and I'd prefer to use stainless anyway, but till I can find a cheap source...QuoteFor small dia nylon tubing? But a sharp knife makes a very clean cut, especially if you slide the blade a bit. I have various sizes of copper tube cutters, flaring tool and expander.Quote from: DTJ on March 26, 2017, 10:57:26 amAlready started buying some stock.https://www.aliexpress.com/item/10pc-lot-6mm-to-1-4-Brass-Pneumatic-fitting-Brass-Fast-Coupling-Push-in-Quick-Joint/32750650161.htmlQuoteHopefully my collected junkpile has enough solenoid valves to do me for a while. Pic 4 is just some of it. (Not the solenoids)But coincidentally I'm currently looking for replacement coils for 4 old bellows valves I'm restoring and repurposing. They have 110V 60Hz coils. Need to find 240VAC (preferred) or 24VAC 50Hz coils of the same shaft dia (13mm 1/2") and length (about 40mm, 1.5")Pic 1 is one of the valves, minus body and all the O-rings and screws. The hard part is, the brass valve bodies have copper tubing silver-soldered in, some of which I'll have to remove. Fingers crossed I can do it without wrecking the valve bodies. (See pic 2 & 3)

author: apelly
author_rank: Unknown
timestamp: March 27, 2017, 01:07:43 am
content: Quote from: TerraHertz on March 26, 2017, 11:45:34 pmI'll be watching to see how you pull this off! I totally failed to find similar coils for a project a while ago.

author: BradC
author_rank: Super Contributor
timestamp: March 27, 2017, 02:01:31 am
content: Quote from: TerraHertz on March 26, 2017, 11:45:34 pmAnother source for coils that might bear fruit is a refrigeration gear supplier. High pressure fridge solenoids come in all sorts of shapes and sizes, and you'll find some monster replacement coils. Try Actrol, Heatcraft or Airefrig and see how you get on.Best to walk in with your solenoid. The guys behind the counter are generally willing to help out with something out of the ordinary, although I've had less luck with Heatcraft than the others.

author: TerraHertz
author_rank: Super Contributor
timestamp: March 27, 2017, 10:20:43 am
content: Quote from: BradC on March 27, 2017, 02:01:31 amHey! Yeah! Thanks for reminding me. I found a big refrigeration parts supplier not far away, early last year I think. Had forgotten. Now I just have to remember what they were called. Uh... holy shit, my memory worked for once.http://www.stareast.com.au/

author: vk6zgo
author_rank: Super Contributor
timestamp: March 28, 2017, 12:49:46 am
content: Back in the day, I became way too familiar with "Puregas" dehydrators.These things used compressors to produce high pressure dry air, which was then applied to a regulator, & used to keep antenna coax cables moisture free.They used the brass "ferrule & olive" tubing connectors, which usually worked OK in the low pressure side of things, but were a constant source of problems in the HP side.Undo them once, & the olives were unusable, so you always needed new ones.They were US sizes, & hard to obtain, except from "Puregas", who "charged like a wounded bull".All the locally available sources only stocked old Brit Imperial or Metric olives & ferrules.I found a place called "Fluidair", who did have some stock, but recommended we go for the push-lok connectors, which were available in all types of threads.We did so, with no more problems.i'm not sure if "Fluidair" are West Oz only, or if they are in your State, too.They were very knowledgeable about pneumatic stuff, even supplying a solenoid that Puregas couldn't find, & in fact, denied they ever used!

author: BradC
author_rank: Super Contributor
timestamp: March 28, 2017, 01:10:55 am
content: Quote from: vk6zgo on March 28, 2017, 12:49:46 amOlives have always been a one-shot affair. Just like copper crush washers. Yeah, sometimes in non-critical applications you'll get away with it, but any "deform on tightening" seal is a one use only.Thanks for the tip on "Fluidair", I'll add that to the go-to list. Also in WA, "Couplers" in Malaga are the ducks nuts for specialist fittings.

author: DTJ
author_rank: Super Contributor
timestamp: March 28, 2017, 01:37:52 am
content: Quote from: BradC on March 28, 2017, 01:10:55 amIn case you are SOR there's a Couplers store down in O'Connor that looks like it's split from the franchise and now trades as "ozlink". As you say they are good for fittings.http://www.ozlinc.com.au/

author: BradC
author_rank: Super Contributor
timestamp: March 28, 2017, 01:48:58 am
content: Quote from: DTJ on March 28, 2017, 01:37:52 amExperience is they are not quite as diverse in range as the Malaga mob, but it depends what you are looking for. There's another similar mob in Welshpool, but again YMMV.Always nice to get a list of places to try when you really need that hard to source widget at 4.30 on a Friday arvo.

author: DTJ
author_rank: Super Contributor
timestamp: March 28, 2017, 03:48:18 am
content: Quote from: BradC on March 28, 2017, 01:48:58 amWhile on handy suppliers, Porter Agencies in Malaga have some good stuff.Odd nuts/bolts, electrical tools, chassis punches.Agents for Heyco / Microplastics / Keystone.Their website is a bit crappy but the guy running the place is helpful.http://porteragencies.com.au/

author: BradC
author_rank: Super Contributor
timestamp: March 28, 2017, 07:47:09 am
content: Quote from: DTJ on March 28, 2017, 03:48:18 amThankyou! Scribble, scribble, copy, copy.. Malaga is about 5 minutes from me so every tip is helpful

author: TerraHertz
author_rank: Super Contributor
timestamp: March 29, 2017, 02:04:15 am
content: Quote from: apelly on March 27, 2017, 01:07:43 amSuccess! Stareast had a coil that fits. Tested it and it works. Makes the plunger pull up with a confidence-building thunk.Only two slight problems:* It's slightly too long. But I can fix that by either grinding a little plastic off the ends, or making a tube nut.* The price. $30 ea, and I need up to 4. So for now I just got one to try. Can buy more if needed, and after I've succeeded in removing unwanted pipework from the valve bodies without ruining them.Probably should make nylon nuts anyway. The coils are designed to use a plastic end-clip. A metal nut will act like a shorted turn (in any field residual outside the internal poles), and increase dissipation. I notice the internal pole pieces have a current-stop gap.Bonus - I happen to have some of the connector shrouds that fit these.

author: NiHaoMike
author_rank: Super Contributor
timestamp: March 29, 2017, 02:40:02 am
content: Have you considered just using the 120V coils with series resistors?

author: TerraHertz
author_rank: Super Contributor
timestamp: March 29, 2017, 03:33:56 am
content: That idea doesn't appeal much. The coils can be on a long time, and are about 15W. Waste of power, plus mounting several 20W resistors (on a heatsink, near a fan.) And, the room still has no aircon. Though, I'm probably going to have to do something about that.Still looking for an Aliexpress source of suitable coils.