Hellermann "Twingrip" crimp terminals/lugs - Aerospace

[ScottBouch]

Hi all,

I'm trying to locate some new old stock crimp terminals. This is quite a specific request for a particular type, the "Twingrip"

Introduced by Hellermann in the 1950's, the "twingrip" was a range of uninsulated, plated copper, pressure crimp terminals. They consisted of a main lug with barrel for conductor, plus a thinner plated copper sleeve, or thimble which fitted over the barrel and was longer to crimp down onto the insulation. the crimp tools produce a hexagonal shaped crimp over the conductor area, and insulation grip area.

If insulation was required over the crimped part, a Helsyn sleeve would be fitted.

There were three sizes, 0, 1, and 2, these used green, red, blue colour coded tools respectively.

I have some instrumentation to connect to, with narrow channels leading up to the terminal screw, which is where these crimps are ideally suited due to their lack of bulk, being uninsulated.

I also have the complete crimping set, with all three MK3 crimp tools, their "go no-go" calibration gauges, both sizes of insulation stretching pliers, and Hellerine oil. Just missing the terminal lugs to crimp!

I'm particularly interested in size 0 terminals as the wiring I'm interested in crimping to is only small (24 - 20 AWG for size 0).

Really I am mostly interested in the smaller rings, 8BA to 4BA, but all the size 0 terminals in this size that I have found Stores Ref numbers for are:

1, Ring tongue:
5/16” - 5X/7299
0BA - 5X/9709523
2BA - 5X/9450393
4BA - 5X/9462951
6BA - 5X/1010324

2, Quick release:
4BA - 5X/9450396

3, Inline splice
5X/7310

4L, Flag (left hand)
4BA - 5X/7317

4R, Flag (right hand)
4BA - 5X/7318

5, Cranked:
4BA - 5X/7316

8, SBAC ferrule (bullet)
5X/9726815


Other types are also included, but have no stores ref numbers:

6, Ring tongue long reach
4BA

7, Ring tongue short reach
4BA
6BA
8BA

I know these are old items, and likely bagfuls have been weighed in for scrap over the decades, but in restoring mid-century aircraft equipment if I can find the right terminal, it all helps with maintaining the originality, and producing wiring harnesses to original specs.

Many thanks, Scott.

[ScottBouch]

PS:

I also am lacking a copy of AP1086 section 5X, which would be useful in this research!

Cheers, Scott

[ScottBouch]

Here is an example of the 4BA Quick Release lug, Stores Ref. No: 5X/9450396.

It's marked H0, or 0H depending on which way up you are. The 0 here refers to the crimp size, and tool to use. The H may stand for Hellermann, like the Helsyn Sleeves are identified with H numbers. Note the previous diagram only showed the numbers, not the letter H, so this may have been added to the lugs some years later.

The 0 (without H) marked on the outer sleeve is indented by the crimp tool, to show the correct tool size was used.

Cheers, Scott

[ScottBouch]

An example of the 4BA Ring Tongue lug, Stores Ref. No: 5X/9462951

Same size 0 markings as the quick release previously discussed.

[Cruisin Marine]

Could you not use the crimp terminals with coloured hard plastic sleeve over them by removing the plastic sleeve's, it is easy to do and they become much smaller.

[ScottBouch]

Originally Posted by Cruisin Marine

Could you not use the crimp terminals with coloured hard plastic sleeve over them by removing the plastic sleeve's, it is easy to do and they become much smaller.

Hi, yes, I have had a go at that...

Trouble is the modern small "red" size is too large for the size 0 tool (for the wire sizes I intend to use)... With red insulation removed, it fits the size 1 tool. Depending on wire used, I have had to double over the conductor to make it grip - ie, using this solution I will end up using wire thicker than needed, just to fill a crimp terminal.

But it's a fall-back option if it comes to it.

I keep thinking there must have been bags and bags of these go to be weighed in by scrap metal dealers.

Cheers, Scott.

[ScottBouch]

Here is an experiment I conducted earlier, using a red insulated crimp blade/spade connector... these are the only type I have which have an additional metal sleeve inside the insulation.

The wire is 0.5mm2, with 2/3 of the strands doubled over, 1/3 cut at point of bend, this filled up the bore of the crimp snugly.

There are scratches and marks on the metal sleeve form me trying to cut off the plastic insulation, it wasn't all that easy to do without causing some damage.

Crimped with No. 1 tool, as metal body too big for No. 0 tool.

End result was that the insulation sleeve was fully crimped into hexagonal shape, but not very tight onto the insulation. The main conductor crimp did grip the conductor nicely (with the selective doubling over), but it wasn't fully compressed into the hexagonal shape, and tool size imprint was not successful.

An earlier attempt with the same 0.5mm2 cable but not doubled over resulted in it being pulled straight out with little effort.

The hunt for original correct lugs continues!

Cheers, Scott.

[ScottBouch]

Just going through the Lightning illustrated parts catalogue, found an alternative to the size 4BA ring tongue in size 0 (5X/9462951) is the AMP 323199, which are available in quantities of 1000, at £2.41 each + VAT!!!

https://uk.farnell.com/amp-te-connec...551?ost=323199

TE's site, with drawings: https://www.te.com/usa-en/product-32...&source=header

I've just ordered x 10 free samples of the AMP alternative from TE, which will be interesting to evaluate! Shame I couldn't order a few more as 50 to 100 probably would have been enough!

[Uncle Bulgaria]

Would it work with normal terminals of the type with cylinders for the cable?

I've seen a few of the crimp set I guess you have on eBay recently. They look very nice, but if the crimpers don't work with anything except obsolete terminals I might pass and just get the Helsyn sleeve expanders separately. They still seem to be useful, anyway...

[ScottBouch]

Hi Uncle Bulgaria,

Yes, there are some on ebay currently the same. The two stretchers are very nice, but you could buy them individually cheaper than the whole set.

Those terminals you shared are for wire sizes 0.5mm2 to 1mm2, so sound like the equivalent modern red size I have tried (minus insulation) with partial success in the size 1 tool, however it is nice to see some BA size rings instead of Metric.

I did some more analysis of the Lighting IPC last night, found numerous more crimp stores ref numbers with corresponding HC numbers, and descriptions, so am collating a table of this info to help the search.

Thanks, Scott

[Uncle Bulgaria]

Can the crimpers only be used on terminals where the wire goes into a cylinder, rather than the ones where the two lugs get squeezed over the conductor and insulation?

I make the smallest size you need particularly small, ~0.3 - 0.5mm2 from the Hellermann conversion chart in one of those sets (22-20AWG). Farnell has one uninsulated fork option in that size which is this one.

These ring ones have a 'maximum' wire gauge allowance of 22AWG.

They do also have some with a 'natural' insulation in nylon that would look a lot less obtrusive than the red, blue or yellow of the current offerings. I guess the crimp gauge is taking the insulation thickness into account so removing it changes the OD without affecting the ID. Here's a ring one, but there are several in other styles.

[bigfathairyvika]

Tip for removing the plastic covers from ordinary crimp terminals is to put a clean dry soldering iron on the connector holding it down on something that won't burn and pull the plastic cover off quickly as soon as it frees off.
This leaves no scratches.

Also, are these connectors your looking for have a cross hatch pattern already on the crimped part before crimping?

[ScottBouch]

Originally Posted by bigfathairyvika

Tip for removing the plastic covers from ordinary crimp terminals is to put a clean dry soldering iron on the connector holding it down on something that won't burn and pull the plastic cover off quickly as soon as it frees off.
This leaves no scratches.

Also, are these connectors your looking for have a cross hatch pattern already on the crimped part before crimping?

Thanks for the tip there!

Well, I only have seen these crimp terminals post-crimping, never seen an un-crimped one, so can't really answer about patterns in the metalwork on the crimping face...

[ScottBouch]

Today I received my free x10 AMP 323199 sample terminals from TE.

The Lightning IPC stated these as an alternative to 5X/9462951, so I had assumed they may be able to fit the same tools, but looking at them I don't think so as they are intended for diamond grip (like a PIDG tool [pre-insulated diamond grip], but for uninsulated terminals)... I will try crimping one in these tools to see if it will work though. I think when the IPC says suitable alternative, the wireman would be using the correct tool for the crimp, resulting in a diamond grip tool being used instead of the Hellermann hexagon grip tool.

Cheers, Scott

[ScottBouch]

I have just tried crimping a piece of Unitersil 20 (20 AWG), using a modern AMP 323199 crimp lug (for 22 to 16 AWG) in the Hellermann Mk3 tool, size 1 (for 18 to 16 AWG Hellermann Twingrip lugs), and it worked out ok!

The insulation strain relief of the 323199 crimp is quite large, so during crimping, the sides actually zig-zag crumpled inward toward the insulation, which is something I've seen on other proper Hellermann Twingrip crimps from aircraft, so not too shabby.

There is no way this crimp lug would fit the size 0 tool (for 22 to 20 AWG), so I think that the original Hellermann Twingrip crimp lugs must have had a thinner wall thickness.

Cheers, Scott

[ScottBouch]

A friend, Terry has just pointed me at section 5X of AP1086... I had a copy all along under my nose! If I was Homer Simpson, I'd be saying "Doh".

So, for completeness, attached is a 2 page extract of section 5X with a long listing of Hellermann TwinGrip crimp terminals, 5X ref numbers and what could be Hellermann part numbers.

Now I should be able to determine the exact ones I need for my projects!

Cheers, Scott.

[G6fylneil]

For many years I've used the small yellow crimps, (e.g. RS 239-4183) for terminals with "narrow grooves", with an AMP 26-22 PIDG crimper, but I've never seen a "proper" PIDG crimp (with the metal sleeve inside the plastic) in that size.

[ScottBouch]

Thanks for that these are the types of channels I'm up against:

Rotax / C.W.C. switches, and Desynn position indicators.

I think the cranked crimp terminal may be used on two of the switch connections. The Desynn almost looks like bare wire ends would be the only thing that would fit! Maybe a solder tag might just do it...

Cheers, Scott

[G6fylneil]

The switches in post no.18 look to have been designed for a Ross Courtney eyelet type of cable termination, with no provision for insulation strain relief.

[ScottBouch]

Thanks, I can see what you are thinking for the Desynn! The channels are tiny.

I've not seen those Ross Courtney eyelets used in the EE Lightning, but have seen restorers use them on older (WW2 era) piston engine restoration projects for big chunky ignition system wiring.

I do have some illustrated parts catalogues for a couple of the Lightning Mk's, so I can have a look, however, the cable system BoM's are a pig to follow, with not much info as to which loom goes where and to which device... So it will take a while to determine the rings used, if it is at all possible.

Cheers, Scott