I keep losing my 4mm lantern tips on fluke probes. Anyway to fix them permanent? - Page 1
Forum section: electronics / testgear

author: Cicada
author_rank: Regular Contributor
timestamp: June 26, 2025, 08:45:16 am
content: HiMy fluke 177 use these probes.https://za.rs-online.com/web/p/multimeter-leads/4687415I take of the plastic covers at the tip of the probes to expose the lantern tips (fluke part number 4004617) to push them into 4mm banana sockets.https://testermans.co.uk/product/fluke-4004617-4mm-adapter-lantern-replacement-tips/It does not take long for the lantern tips to work themselves loose and become lost. Has anyone figured out a relaible solution to prevent this from happening? Maybe some sort of locktite. if so which number and does it influence conduction?I do not plan to ever remove the lantern tips so I have considered putting a spot of 2 tube epoxy glue on them to lock them in place permanently. Would like to hear thoughts about this option.Thanks fellow meter heads.

author: RoGeorge
author_rank: Super Contributor
timestamp: June 26, 2025, 09:13:47 am
content: Instead of gluing, maybe try to fit inside some aluminum foil, or copper (from PCB), or a thin wire along the probe tip.

author: jpanhalt
author_rank: Super Contributor
timestamp: June 26, 2025, 10:17:02 am
content: I am not sure how the Fluke tips are made. If like this:The lantern snaps over the stem. That seam (circled) might be spot welded. In that case, they are very hard to remove. If just held by spring action, I doubt any glue would work, but a little solder might help. If you have a battery welder or know someone with a TIG welder, you might be able to just touch the seam to keep it from splitting. If the bulb on the tip is missing, I'd get new plugs with a bulb. You could also try the solder/weld approach to add a bulb.

author: Cicada
author_rank: Regular Contributor
timestamp: June 26, 2025, 10:49:47 am
content: @jpanhaltThanks for the reply. The picture attached is perhaps a bit more explanatory.I don't want to use loctite on the threats for fear of poorer conduction. That is why I though it might be good to epoxy glue the lantern tip as shown in the picture.But I would much rather rely on the wisdom of the community.If the picture does not attach to this post please look here for it.https://postimg.cc/KKMB115TKind regards,Cicada

author: jpanhalt
author_rank: Super Contributor
timestamp: June 26, 2025, 11:07:27 am
content: I see, there is no bulb at then end, but they are threaded. If you need to keep the threaded end from opening up, a tiny tack weld on the lantern seam will stop that. If they unscrew, that's just a matter of being sure they are screwed on. Any sort of thread locker or epoxy will affect the ability to swivel/rotate.

author: tooki
author_rank: Super Contributor
timestamp: June 26, 2025, 11:10:32 am
content: Tiny circlips at the end, in the little groove behind the point?Slightly damaging the threads to make them grip harder?

author: watchmaker
author_rank: Unknown
timestamp: June 26, 2025, 11:26:06 am
content: Use copper tape on the threads in the fashion of teflon tape used by plumbers? Al foil? I like the circlips if you can find them.

author: squadchannel
author_rank: Frequent Contributor
timestamp: June 26, 2025, 11:34:36 am
content: I will use adhesive lined shrink tubing and shrink the tip.Since it's a hassle, I will remove the cap, apply adhesive with a glue gun, and then back the cap. I don't think it will take much force, so it should be fine.MOD:adhesive lined shrink tubing requires a higher temperature than regular heat shrink tubing. The probe body(maybe PVC?) may melt.Cover with regular heat shrink tubing and wrap the wire around the slight dent at the top.

author: tooki
author_rank: Super Contributor
timestamp: June 26, 2025, 12:02:44 pm
content: Quote from: squadchannel on June 26, 2025, 11:34:36 amWhile I don’t think that the temperature to melt adhesive-lined heat shrink would cause any trouble whatsoever, I also doubt that heat shrink would do very much to solve your problem. And I think adding insulating materials anywhere to the probe tip seems like a bad idea.Why not do one of the many better ideas presented in this thread?Quote from: squadchannel on June 26, 2025, 11:34:36 amWhat wire?

author: squadchannel
author_rank: Frequent Contributor
timestamp: June 26, 2025, 12:17:22 pm
content: is it mean the comes off the cap marked in red, right?cover the part marked in green with shrink tubing and wrap the part marked in black with wire to prevent it from coming off.is it cone shaped, so secure with wire, the shrink tubing doesn't come off, the cap won't come off either.Wait, I get it now. You mean the metal part of the banana comes off?from the photo, even with the "banana metal" attached, the tip (chip part, metal part of the probe) should be exposed.If there is no need to remove it, I would solder it in place.

author: Cicada
author_rank: Regular Contributor
timestamp: June 26, 2025, 12:48:34 pm
content: Quote from: squadchannel on June 26, 2025, 12:17:22 pmNo the part shown in the picture below just undo it self over time. No matter how hard I tighten the thread.A month after replacing the lantern, shown in the picture below, I try to plug the probe tip into a 4mm banana socket and it is gone on one probe. So it is clear it comes loose and fall away by itself.

author: squadchannel
author_rank: Frequent Contributor
timestamp: June 26, 2025, 12:53:48 pm
content: whether the screw loosens or the banana spring comes out, soldering will prevent it from coming off. adhesives cause conductivity problems

author: BILLPOD
author_rank: Frequent Contributor
timestamp: June 26, 2025, 01:47:51 pm
content: Good Morning Cicada, My Brymen probes have the same type of lanterns. When I have some that loosen up, Idingup the threads on the probe, very lightly, and then they screw on with some resistance, but they don't loosen up. I usually use pliers or a punch & hammer.

author: mahi
author_rank: Regular Contributor
timestamp: June 26, 2025, 03:13:26 pm
content: Cicada:Since you want to have the lantern tips on permanently, why not switch to probes that have fixed lantern plugs? For example theFluke TP74/ TL74. The lantern tips are not removable, but they can rotate. The TP74 are just probes without leads. The TL74 is the version with (silicone) leads, but I can't find it on the Fluke website anymore. Maybe it is no longer manufactured?Note that the Fluke TP74/TL74 are primarily for electrical work. The tips are not very sharp, so they are not great for electronics.

author: mqsaharan
author_rank: Regular Contributor
timestamp: June 27, 2025, 02:25:24 am
content: Quote from: Cicada on June 26, 2025, 08:45:16 amHi Cicada,When you screw these lantern tips on, they get tightened up by biting into the plastic at the base of the probe tips. Usually they stay there. But if they don't you can try tightening them up using a nose pliers.If you'll try to use some glue/epoxy on the threads, it could get intermittent because they are otherwise very loose on the probe tips. Or you can try to use epoxy after the threads, at the base of the tips. I would suggest you to make the plastic surface rough at the base of the probe tips as well as the base of the lantern tips and last one or two threads by using a small/thin file so that the glue/epoxy stays on.If they still don't stay on, you can use the solution presented in reply #12 by BILLPOD.Or If that doesn't work, you can try to crimp the lantern tips (after putting them on, of course) at the threaded part using an appropriately thin crimping tool or may be using just a small hammer. It'll take some effort but I'm sure they'll don't get loose after that.I hope it helps.Edit: small corrections.

author: tooki
author_rank: Super Contributor
timestamp: June 27, 2025, 11:56:22 am
content: Quote from: squadchannel on June 26, 2025, 12:53:48 pmYou were worried that using adhesive-lined heatshrink would melt the probe body, but now you’re recommending soldering the banana adapter directly onto the tip? Soldering, which requires MUCH higher temperatures than heat shrink?

author: Fungus
author_rank: Super Contributor
timestamp: June 27, 2025, 11:58:21 am
content: Quote from: Cicada on June 26, 2025, 12:48:34 pmLoctite? That's what it's for...

author: tooki
author_rank: Super Contributor
timestamp: June 27, 2025, 11:58:45 am
content: Quote from: Cicada on June 26, 2025, 12:48:34 pmSeriously, just do what I suggested earlier and BILLPOD suggested again just now: damage the threads to make them hard to turn. Then use some pliers to grip the banana adapter and screw it on.

author: tooki
author_rank: Super Contributor
timestamp: June 27, 2025, 12:00:00 pm
content: Quote from: Fungus on June 27, 2025, 11:58:21 amUsing Loctite on threads that carry electricity? Isn’t that just begging for a poor connection?

author: Fungus
author_rank: Super Contributor
timestamp: June 27, 2025, 12:09:41 pm
content: Quote from: tooki on June 27, 2025, 12:00:00 pmI don't think the threads is the only place they make contact, but ... good point..

author: Fungus
author_rank: Super Contributor
timestamp: June 27, 2025, 12:12:01 pm
content: Common sense: Get some banana <-> banana leads and forget about the lanterns.

author: TERRA Operative
author_rank: Super Contributor
timestamp: June 27, 2025, 01:28:28 pm
content: Quote from: tooki on June 27, 2025, 12:00:00 pmLoctite fills the airgaps between the threads and sets hard, the tight metal-to-metal contact area will remain as such.It might even be the case that the exclusion of air keeps the contact area gas-free and hence free from oxidation.

author: tooki
author_rank: Super Contributor
timestamp: June 27, 2025, 08:59:49 pm
content: Quote from: Fungus on June 27, 2025, 12:12:01 pmFYI, as I understand it, the intended purpose for them is actually not to use them as banana plugs as such, but rather to make solid contact inside European (and other round-pin) mains outlets. (Hence why Fluke appends an “E” to their probe models that include the lantern tips.)But yes, you are of course absolutely correct that banana-banana leads work for that, too!

author: artag
author_rank: Super Contributor
timestamp: June 27, 2025, 10:55:26 pm
content: I have some probes made by AMP. They have a good sharp tip but no 4mm lantern. However, the sharp tip section pulls right off and behind it is a 4mm plug. Unfortunately it's the cursed safety type that only works in some sockets. I'd very much like to find similar probes with the same tip feature but properly functioning plugs with either no cover or a spring-retracting one. I am at a loss to understand why multimeter probes need covers, since multimeters don't typically emit dangerous voltages.

author: tooki
author_rank: Super Contributor
timestamp: June 28, 2025, 02:54:21 pm
content: Quote from: artag on June 27, 2025, 10:55:26 pmUmmm… so browse some test and measurement catalogs for probes that go on banana cables (Fluke/Pomona, SKS Hirschmann, Stäubli, and Keysight all sell such probes, as do many others), and the use cables with unsheathed or retractable-sheath plugs?Just don’t use those for mains — the last thing you want is to accidentally not plug a cable in all the way and then inadvertently make contact with the exposed banana plug while probing mains voltage!Quote from: artag on June 27, 2025, 10:55:26 pmSorry, do you mean “covers” as in the sheath on safety banana plugs, or probe covers that sheath the shaft of the probe tip?Sheathed banana plugs are fundamentally to prevent you from inadvertently touching any exposed metal, as well as preventing loose wires or whatever from coming into contact with them. Probe tip covers are to prevent accidental shorts, which in high-energy circuits can result in dangerous arc flash events. But they’re also handy for not accidentally frying delicate circuits by accidentally shorting things.Modern CAT ratings require sheathed banana plugs and probe tips. The Fluke TL175 (and TL175E) have retractable probe tip sheaths: with the sheaths extended, they meet CAT III 1000 V and CAT IV 600 V ratings. With the sheaths retracted, they meet only CAT II 1000 V. (The probe design actually shows which CAT rating is currently active depending on the current sheath position.)Quote from: artag on June 27, 2025, 10:55:26 pmNo, but you mightmeasurethem. You know that CAT III 1000 V and CAT IV 600 V ratings require the product to tolerate (without creating a safety hazard) spikes up to 8 kV, right? But even without hazardous voltages, if you accidentally short the positive and negative terminals of a lithium-ion battery, for example, it might be only around 4V, but the fault current can be enormous. A single 18650 cell can easily have a short-circuit current between 50-100A!! Shorting that will ruin your day (and your probes).

author: tooki
author_rank: Super Contributor
timestamp: June 28, 2025, 03:05:40 pm
content: Quote from: TERRA Operative on June 27, 2025, 01:28:28 pmI did a bit of googling and as best I can tell:1. Applying thread locker to electrical mating surfacesbeforemating them is a spectacularly bad idea. Because it coats the surfaces before mating, the mating surfaces themselves can’t interact the way they should (rubbing, scraping, compressing, etc) since the thread locker creates a lubricating layer between the mating surfaces, resulting in high contact resistance (well into whole ohms). Not a problem for voltage measurements, but very bad for current measurements.2. Adding thread lockerafterscrewing down is prooooobbbbably OK, because whatever air gaps exist, exist after the mating surfaces were able to interact, and thus would have been exposed to air anyway. But I’d still probably avoid it, if alternatives are possible.Quote from: TERRA Operative on June 27, 2025, 01:28:28 pmDoes that matter? The areas where the mating surfaces are actually making contact are already largely gas tight. So the oxidation will only occur where they aren’t touching solidly.But overall, it just seems like a very bad idea to me. Especially since there are alternative methods that don’t involve contaminating the threads with an insulating material.

author: TERRA Operative
author_rank: Super Contributor
timestamp: June 28, 2025, 03:07:56 pm
content: Quote from: tooki on June 28, 2025, 03:05:40 pmIf the mating surfaces are gas tight against oxidation as per your own statement, then they are also tight against loctite too.It's a what? Not quite 4 digit multimeter? It's not like you are measuring out to 8.5 digits here...

author: tooki
author_rank: Super Contributor
timestamp: June 28, 2025, 03:09:45 pm
content: Quote from: Fungus on June 27, 2025, 12:09:41 pmI’m really not sure; when I’ve seen these things, they’ve looked more like the probe tip itself is fairly loose inside the lantern barrel.I’ll find out in a week when I go back to work (I’m on staycation now). I ordered a set of TL175E probes just before I left, so they should be waiting for me when I return.

author: tooki
author_rank: Super Contributor
timestamp: June 28, 2025, 03:15:07 pm
content: Quote from: TERRA Operative on June 28, 2025, 03:07:56 pmOnly if applied AFTER mating.If you apply it before, the lubricant effect of the thread locker will leave far more areas separated by a thin film of thread locker. Hence why I said that applying it afterwards is “probably” ok. I still wouldn’t do it.Quote from: TERRA Operative on June 28, 2025, 03:07:56 pmAn additional 10 ohms of resistance (per probe! So 20 ohms total.) on a resistance or current measurement could really ruin your day, depending on what’s being measured.Again, since there exist other methods that don’t run any of these risks, why take the risk?!? It just makes no sense to me to do something that is even justpotentiallyproblematic when a no-risk alternative exists.

author: jpanhalt
author_rank: Super Contributor
timestamp: June 28, 2025, 03:58:12 pm
content: Quote from: tooki on June 28, 2025, 03:05:40 pmEvery Loctite (originally a good ol' Cleveland, OH company) I have used was "anaerobic" curing. Some might be pressure too, but the real genius ($$) in Loctite was that oxygen inhibited the polymerization. That may not really be part of this discussion. I think the threaded "lantern" was developed to allow the contact to swivel without adding wear to the socket, as regular bulbed end banana plugs allow. Fluke simply took that path. It could have gone with a conventional "lantern" with a small C-clip (or E-clip) to retain the lantern on the narrow end of the probe.

author: Fungus
author_rank: Super Contributor
timestamp: June 29, 2025, 02:21:55 pm
content: Quote from: tooki on June 27, 2025, 08:59:49 pmMe? I'd get an IEC cable, plug that in, then probe the other end of the cable. It's FAR easier than fighting to open the shutters on a European socket (those things are tough to defeat). The probes are usually a tight fit and you can just put them in the slots and leave them there while you put in the plug for a reading.If it was something I did alotI'd chop the connector off the other end and substitute some banana plugs for attaching the meter to the cable. That way I wouldn't have to touchanythingrisky when I'm taking a measurement - connect up the meter, set it to AC,thenput in the plug.Either way: I wouldn't be using lantern connectors on probes.

author: artag
author_rank: Super Contributor
timestamp: June 29, 2025, 04:56:35 pm
content: Quote from: tooki on June 28, 2025, 02:54:21 pmBut if you're probing a high voltage circuit, the danger is primarily from the circuit itself. You have a finger guard on the probe to stop your finger sliding down to the tip and if it does, it's going to hit the terminal you're probing. A shroud around the pin just makes it harder to see what you're doing, increasing the chance of making a mistake or bridging two points.These guards are like the classic underthought safety guards on lawnmower triggers etc. - invented by someone with one sort of misuse in mind who's never actually used the thing.

author: tooki
author_rank: Super Contributor
timestamp: June 29, 2025, 05:03:48 pm
content: Quote from: Fungus on June 29, 2025, 02:21:55 pmYeah, their utility has certainly dramatically fallen with the advent of shuttered receptacles! And I agree with you about using a mains cable with banana plugs on it (though for this specific application, they should unquestionably be safety banana plugs!!).

author: kmoonwalker
author_rank: Frequent Contributor
timestamp: June 29, 2025, 05:12:58 pm
content: Quote from: Cicada on June 26, 2025, 08:45:16 amIn my modest opinion it would be way safer/much more sturdier to use just 4mm banana to banana cable between your meter and those sockets you need to plug intoQuote from: tooki on June 29, 2025, 05:03:48 pmthere are special adapters that you plug into wall socket and measure without fighting with shuttershttps://www.tme.eu/pl/details/adptr-sct-eur/akcesoria-pozostale/beha-amprobe/?brutto=1&currency=PLN&gQT=1or you take a cable with plug, cut it and make 4 mm sockets on the other side+ as mentioned banana to banana cable - more sturdy, easier to replace and waaay more safer in case

author: tooki
author_rank: Super Contributor
timestamp: June 29, 2025, 05:38:19 pm
content: Quote from: artag on June 29, 2025, 04:56:35 pmYou’ll have to take that up with the IEC, since it’s their CAT ratings that mandate these things.With that said, I don’t think you’re being entirely realistic about the pros and cons of tip shrouds. On one hand, you can get CAT IV 1000V probes with shrouded tips that are nearly as slim as traditional unshrouded ones; these don’t impede visibility at all. (For example,WAGO 206-912andElectro-PJP 402.) For lower CAT ratings — which are surely the overwhelming majority of situations EEVblog members actually work in — even thinner shrouded options are available.On the other hand, remember that CAT ratings aren’t just about voltage, it’s fundamentally aboutenergy, with CAT IV circuits havingsignificantenergy behind them. The hazards there aren’t just from touching it, it’s from arc flash, which causes devastating, often lethal injury.But even in low-energy circuits where there is zero risk of arc flash, it absolutely can happen that you’re probing somewhere and don’t notice the side of the probe tip coming into contact with something else (for example, a grounded enclosure, or a heat sink at full DC-rectified mains voltage). No arc flash, but it’ll still ruin your day.Quote from: artag on June 29, 2025, 04:56:35 pmYou don’t know that. That’s an awfully arrogant stance to take.Since you never actually answered my question about whether your complaint is with shrouds on the banana plugs vs. shrouds on the tips, here’s your original complaint:Quote from: artag on June 27, 2025, 10:55:26 pmWhat exactly is it you’re after? Your description is not clear. Here, it sounds more like you’re unhappy about shrouded banana plugs, but then your reply above is unhappiness about shrouded probe tips. Can you please clarify? Or take photos of what you have, and then explain the issue more clearly?I’m absolutely suresomebodymakes the perfect probe for you. If you express your wishes clearly, maybe we can help you find them.

author: tooki
author_rank: Super Contributor
timestamp: June 29, 2025, 05:44:28 pm
content: Quote from: kmoonwalker on June 29, 2025, 05:12:58 pmNice. I have to admit that those weren’t on my radar, since Switzerland doesn’t use Schuko plugs, and with Switzerland being such a tiny market, I don’t think anyone makes an equivalent product for the Swiss outlet. Maybe someone makes one, but I have yet to encounter them in any catalog or vendor.

author: kmoonwalker
author_rank: Frequent Contributor
timestamp: June 29, 2025, 05:49:49 pm
content: Quote from: tooki on June 29, 2025, 05:44:28 pmthis is mainly for electricians and I would be really surprised if there was nothing for your local market (also some adapter to adapt even one I posted would also do the job)keep in mind that electricians usually have those special meters they simply plug into the socket and they are different matter than such adaptersin case it is not some space engineering to make something like that yourself using some chassis of other device like plugged in power meter or whatever

author: DaneLaw
author_rank: Frequent Contributor
timestamp: June 30, 2025, 11:32:35 am
content: I tend to use the cheap ones from Brymen, which cost like 8 to 10 bucks and is gold-platedand also comes with 4mm banana fittings. incl.https://brymen.eu/shop/silicone-test-leads-bl21s2-t4sc-brymen/if I screw them on with pliers they stay on, if I wanted to try to lock them and get an even tighter screwfit.. I would use some pure copperfoil..(purity 99.99)Cost next to nothing, like 2 bucks..and goes down to 0.001 or 0.01mmhttps://www.aliexpress.com/item/1005009169647083.htmlThough I haven't tried it, so not sure what thinnes you would need, that can still screw on, while locking the screw momentum tighter or if its even doeable in practise..but I do use pure copper foil for heatsinking purposes on laser diodes, in the absence of a lathe, and to remove gaps between components..

author: BILLPOD
author_rank: Frequent Contributor
timestamp: June 30, 2025, 08:11:11 pm
content: I totally agree with DaneLaw. I love my Brymen probes and have equipped most of my DMMs with them. I tighten up the lantern ends with pliers and they have never loosened up.

author: Fungus
author_rank: Super Contributor
timestamp: June 30, 2025, 08:19:09 pm
content: Quote from: BILLPOD on June 30, 2025, 08:11:11 pmYea, the official Brymen leads are great bang per buck.

author: ksjh
author_rank: Regular Contributor
timestamp: June 30, 2025, 08:47:04 pm
content: Quote from: kmoonwalker on June 29, 2025, 05:12:58 pmOr just use pre-made Schuko to safety banana plug leads available from many different manufacturers like, e.g.https://www.cliffuk.co.uk/products/testleads/leadsmains.htmThere are also different variants of those Schuko to banana socket adapters available. We have bought the VOLTCRAFT DLA-1L 16 for a PhD student in my group. There are also cheaper adapter variants available from Voltcraft, e.g., VOLTCRAFT DMA-1L 16.

author: kmoonwalker
author_rank: Frequent Contributor
timestamp: July 01, 2025, 03:16:27 am
content: if you find them in a good price then certainlyI have a lot of parts so for me it is more time to find right box than actually make such cable