Thread Size

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DBDBrian
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Joined: Mon Mar 30, 2015 11:29 pm

Thread Size

Postby DBDBrian » Sat Jul 02, 2022 4:51 pm

What is the considered opinion as too the size and thread pitch of the frame hangers for the rear footrests / exhaust / rear set gear linkage. 7/16" X 20 Tpi (UNF) is quoted by some suppliers. After measuring what I believe to be an original rear footrest, I concluded it to be 11 x 1.25 MM. ?
Brian
Made in England

Duccout
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Location: Essex UK

Re: Thread Size

Postby Duccout » Sat Jul 02, 2022 5:01 pm

Brian, I think that either will fit - I have seen both sizes quoted as the correct thread for those bolts.

What is other's opinion?

Colin

blethermaskite
Posts: 580
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Location: northern ireland

Re: Thread Size

Postby blethermaskite » Sat Jul 02, 2022 5:26 pm

Pretty sure I have used the 7/16 UNF on all mine for years, however some Ducati singles I have worked on have needed a UNF tap run through the frame boss to get a sweet fit?
Cheers,
George

Bevel bob
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Joined: Thu Apr 15, 2010 8:01 am
Location: Bromley Kent UK.

Re: Thread Size

Postby Bevel bob » Sat Jul 02, 2022 7:01 pm

I filled the holes on my 250 NC with metric bolts ,went straight in .

Eldert
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Location: Hazerswoude Rijndijk Netherlands

Re: Thread Size

Postby Eldert » Sat Jul 02, 2022 8:17 pm

7/16 UNF for sure . factory drawing

passenger footrest.jpg


Eldert
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ducwiz
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Location: near Frankfurt, Germany

Re: Thread Size

Postby ducwiz » Sun Jul 03, 2022 8:38 am

Dear Eldert,

your paper/photo is the first proof for 7/16 UNF I ever saw in my life, thank you!
When I restored my 350M3D, I got the frame, swing arm, main stand etc. powder-coated in black. After the procedure I had to clean also the two threads in question. I used M11x1.25, because a tap was at hand, but a UNF tool not available. Worked fine for me ever since, despite I chose an "inappropriate" thread.

cheers Hans

Jon Pegler
Posts: 471
Joined: Sun May 16, 2010 6:19 pm

Re: Thread Size

Postby Jon Pegler » Sun Jul 03, 2022 10:40 am

The early parts catalogues list part no. 100VS.TE8002 as having a 7/16W x 20 thread. Later revised as part no. 0210.91.965
Not too sure about the W though. The UNF thread has a different profile to a Whitworth thread.
I always clean out the frame with a UNF tap. Seems to work OK for me.

Jon

Ventodue
Posts: 960
Joined: Mon Mar 08, 2010 3:23 pm
Location: Montpellier, France

Re: Thread Size

Postby Ventodue » Sun Jul 03, 2022 12:15 pm

Jon Pegler wrote:The early parts catalogues list part no. 100VS.TE8002 as having a 7/16W x 20 thread. Later revised as part no. 0210.91.965 Not too sure about the W though <snip>


Agree, Jon. The "Whitworth" is definitely wrong, both in the parts book and on that drawing that Eldert posted a photo of (I think the photo was originally taken by Phil Aynsley, btw ...?)

Its a UNF thread.

Eldert
Posts: 811
Joined: Sun Nov 01, 2009 3:23 pm
Location: Hazerswoude Rijndijk Netherlands

Re: Thread Size

Postby Eldert » Sun Jul 03, 2022 1:58 pm

correct Phil A Photo

Eldert

Duccout
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Location: Essex UK

Re: Thread Size

Postby Duccout » Sun Jul 03, 2022 3:53 pm

Definitive answer! Thank you Eldert.


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