Ribbecke Halfling Jazz - technical question

**dko** · 04-10-2025, 11:47 AM

Without this forum I may have never heard of Tom Ribbecke and his great Halfling Jazz Archtop design. Lucky me, I have been following your posts for over ten years. Since 2013 I have been the very satisfied owner of a blond 2009 Halfling Jazz (RCG made).

I think there are not too many Halflings here in Germany.

Now I have a specific technical question about my guitar and I hope someone might have the answer: My Halfling has a bolt -on neck. After twelve years I would like to tighten the two hex-screws, which hold the neck in place (if necessary). But I can’t figure out which size of an allen key I need to do this. 3/16 inch ist too big, 5/64 too small.

Does someone know the right diameter?

**Ukena** · 04-10-2025, 02:00 PM

I don't know the right answer, but there's a lot of room between 3/16" and 5/64".

If it is not metric, the allen wrenches I have between those sizes are 5/32, 9/64,1/8, 7/64, and 3/32.

Metrically, 3/16" is roughly equivalent to 5mm and 5/64" to 2mm, so 3mm and 4mm are both in that range.

**Gitterbug** · 04-10-2025, 02:59 PM

Why would a US luthier use metric bolts? If 3/16" is too large, then my guess is 4 mm, which is the key size for M5 bolts. Even these sound skinny for the job (ok, the washers look like 12 mm and the black bolts are hardened steel), so 3 mm key for M4 bolts sounds way too small. I thought everyone in Europe would have a stash of 4 mm Ikeators.

**skiboyny** · 04-10-2025, 04:00 PM

Why don't you try asking Tom Ribbecke? He has a Facebook page you might be able to message him. Also a website, email phone number.

**dko** · 04-10-2025, 04:03 PM

Many thanks for your answers. 5/64 was a typing error, should be 5/32 - sorry! I have tried 4 mm (too small) and 5 mm (too big).

**Gitterbug** · 04-10-2025, 04:11 PM

Then it must be 3/16, which makes sense.

**dko** · 04-10-2025, 04:19 PM

Via facebook I didn't get a response to my question. If there is an active Website or email adress I would be thankful for a hint.

**skiboyny** · 04-10-2025, 09:00 PM

Tom Ribbecke | Fine Archtops

**Cunamara** · 04-11-2025, 01:21 AM

Not all Americans are allergic to the metric system. Ribbecke might be one of them. Heck, I can buy metric stuff at my local Ace Hardware store here in Minnesota. We are not completely back-assward.

If 4 mm is too small and 5 mm is too large, then we can take a leap and suggest 4.5 mm as the middle ground. I have a set of Allen keys ranging from 1.5 mm to 10 mm, which includes a 4.5 mm key. So they certainly exist. In this application, a Bondhus style Allen key (has a sort of ball shaped end) might be a good choice because you can address the bolt head from a variety of angles.

**dko** · 04-11-2025, 04:03 AM

Thanks skiboyny. The link on Fine Archtops leads to Tom Ribbeckes facebook account. Seems to be his only online presence nowadays. I couldn't find an email adress there.

Thanks Cunamara. That is my "last hope". Just ordered a 4,5 mm allen key. Even in europe this ist not standard in allen key sets.

**skiboyny** · 04-11-2025, 07:52 AM

[QUOTE=dko;1403436]Thanks skiboyny. The link on Fine Archtops leads to Tom Ribbeckes facebook account. Seems to be his only online presence nowadays. I couldn't find an email adress there.

Thanks Cunamara. That is my "last hope". Just ordered a 4,5 mm allen key. Even in europe this ist not standard in allen key sets.[/QUOTE It's at the very bottom of the page looks like thisContact Us

Phone: (612) 366-7120
Email: [email protected]