Teflon Standoff Insulators - Page 1
Forum section: electronics / general

author: branadic
author_rank: Super Contributor
timestamp: September 06, 2017, 03:44:40 pm
content: Hi guys,I'm searching for teflon standoff insulators, that are used for rf and low leackage, but they seem to be unobtanium. So where to buy them, in particular in germany? Didn't found nothing at Farnell, RS Components, Digikey and MouserOr is there someone out there having them on the desk without any use? Thanks for hints.-branadic-

author: 2N3055
author_rank: Super Contributor
timestamp: September 06, 2017, 04:25:00 pm
content: Quick search :http://export.farnell.com/w/c/connectors/crimp-terminals-solder-terminals-splices/solder-press-mount-turret-terminals/prl/results?st=ptfehttp://www.mouser.co.uk/Search/Refine.aspx?Keyword=PTFE++pinsDoes that help?Regards,Sinisa

author: branadic
author_rank: Super Contributor
timestamp: September 06, 2017, 05:34:14 pm
content: Yes and no, the metal parts are made of brass. Hoped for copper or similar low thermal emf material-branadic-

author: 2N3055
author_rank: Super Contributor
timestamp: September 06, 2017, 05:42:33 pm
content: and thesehttp://www.ebay.com/itm/tft-4-Teflon-Chassis-Standoff-Terminal-push-in-type-NOS-50-pcs-NICE-/182123976629?hash=item2a676f57b5:g:l~UAAOSwKfVXL6wMgood price..If you are only going to use it as a point to join two or more wires, it doesn't have to be in series with the circuit.. So it wouldn't matter then... Your junction will be connected with solder directly.. Or you can crimp connection and than just tack that with solder to post as a structural support... Be creative

author: branadic
author_rank: Super Contributor
timestamp: September 06, 2017, 05:45:26 pm
content: Found these as well, but shipping is extremely expensive (3 times the price for the pieces).-branadic-

author: 2N3055
author_rank: Super Contributor
timestamp: September 06, 2017, 05:46:58 pm
content: Also this one is empty teflon :http://export.farnell.com/itt-cannon/101-1411-001009/terminal-ptfe-bush/dp/1347802So you can press in pure copper by yourself if you need that.....Take care,Siniša

author: Cerebus
author_rank: Super Contributor
timestamp: September 06, 2017, 06:22:13 pm
content: Quote from: branadic on September 06, 2017, 03:44:40 pmI had to laugh, that's so ungrammatical that you almost sound like an East London native (we do horrible things to the Queen's English around here). All you need is the accent: "Didn't faarnd nuffink...".

author: Cerebus
author_rank: Super Contributor
timestamp: September 06, 2017, 06:26:00 pm
content: On a more sensible note, I found a useful looking supplier of PTFE standoffs recently with quite a selection. I can't find the note I made of them but I'll keep looking and get back once I find it.

author: EmmanuelFaure
author_rank: Regular Contributor
timestamp: September 06, 2017, 08:38:26 pm
content: @ branadic : How many do you need?

author: branadic
author_rank: Super Contributor
timestamp: September 06, 2017, 08:59:21 pm
content: QuoteDouble negation is quite common here in germany@ EmmanuelFaureA number of 10 pieces for the beginning would help me a lot.

author: 2N3055
author_rank: Super Contributor
timestamp: September 07, 2017, 06:38:32 am
content: Quote from: branadic on September 06, 2017, 08:59:21 pmSame here in the Croatian, double negation is used to emphasize negativity..

author: HighVoltage
author_rank: Super Contributor
timestamp: September 07, 2017, 07:15:41 am
content: If you have access to a Lathe, you can easily make them yourself, if you only need a few pieces.The raw material is not that expensive.

author: d-smes
author_rank: Regular Contributor
timestamp: September 07, 2017, 07:26:32 pm
content: https://www.surplussales.com/Hardware/Standoffs/index.htmlSeveral styles to choose from.

author: orin
author_rank: Frequent Contributor
timestamp: September 07, 2017, 08:10:47 pm
content: I have a bag of 100 Sealectro 011-2053-000 680... (one bag left on ebay - search for "sealectro teflon").I'll part with some of mine for my cost.

author: 4CX35000
author_rank: Regular Contributor
timestamp: September 07, 2017, 09:19:56 pm
content: Quote from: 2N3055 on September 06, 2017, 05:42:33 pmSeen these Standoffs myself, but the postage comes to 36 USD which is x3 the cost of the item. I suppose the seller could post via a cheaper mailing service, but I decided as my project is only intended for my own personal use.I decided to make my own standoffs using two layers of Virgin Teflon sheets with one sheet acting as the base and the upper sheet with some countersunk holes drilled through and then some copper pins pushed through the holes and pins cut to length. Both sheets are then held on to the PCB via some 5mm stainless steel nuts/bolts.Copper pins are very popular and for my project they are ideal as the physical size is much bigger than typical standoffs from Mouser. But they do need a good clean before use. You can also find gold plated pins and do the same, but I have doubts that they are gold and probably something else considering the price gold these days.

author: carl_lab
author_rank: Frequent Contributor
timestamp: September 08, 2017, 08:04:57 am
content: Quote from: branadic on September 06, 2017, 08:59:21 pmIt is high level bavarian, isn't it?"Niemals nie nicht..."

author: BU508A
author_rank: Super Contributor
timestamp: September 08, 2017, 12:53:48 pm
content: Quote from: branadic on September 06, 2017, 03:44:40 pmBürklin has some of them, for example:https://www.buerklin.com/de/loetstuetzpunkt-fuer-leiterplatten/p/12h2712Edit:Here is an overview from Fischer (in english):http://www.fischerelektronik.de/web_fischer/en_GB/heatsinks/E02.04/Vibration%20dampers%20and%20solder%20terminals/search.xhtml#clsFischer@E02.04

author: branadic
author_rank: Super Contributor
timestamp: September 08, 2017, 02:38:06 pm
content: Thanks, nice finding, but still they are made of brass. However, they are much cheaper then everything else I've seen yet.I wonder if this is typical and the same in the gear shown in the forum by several users? Seems like a decision between low leakage (go for standoff insulators made of brass) and low thermal emf (go for copper clad circuit board and guarding if possible).-branadic-

author: Cerebus
author_rank: Super Contributor
timestamp: September 08, 2017, 03:10:44 pm
content: Quote from: branadic on September 08, 2017, 02:38:06 pmThere is one parameter missing from that set, and that is source impedance. If you're making a 6/7/81/2DVM you expect that your source impedance for the vast majority of measurements isn't going to be super high, so guarding makes sense and is probably enough to kill any influence from leakage. If you're making an electrometer then your entire design is governed by source impedance and the relative error introduced by a few thermal EMFs is a fraction of what 1G or so leakage could do to you.