Drill and tap

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Topic author
Robert Bente
Posts: 74
Joined: Sun Jan 06, 2019 12:19 pm
First Name: Robert
Last Name: Bente
* REQUIRED* Type and Year of Model Ts owned: 1916 runabout, 1921 touring, 1915 touring
Location: Redding, Ca.
MTFCA Number: 49948

Drill and tap

Post by Robert Bente » Mon Apr 08, 2019 10:15 pm

I want to add a priming pump to the intake manifold. It’s a 4 cylinder 1911 Buick and very close to the T, but the T is a sweet heart compared to anything else. I’m drilling holes into a manifold that I would hate to mess up.
Question is, what drill or bore do I use for a 1/4 np 18 thread. 31/64 or something different?
r/s Bob, apprentice machinist.
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Scott_Conger
Posts: 6431
Joined: Sun Jan 06, 2019 11:18 am
First Name: Scott
Last Name: Conger
* REQUIRED* Type and Year of Model Ts owned: '13, '15, '19, '23
Location: Clark, WY
Board Member Since: 2005

Re: Drill and tap

Post by Scott_Conger » Mon Apr 08, 2019 10:26 pm

A question: What is wrong with the hole in the middle of the manifold that is already plugged?
An opinion: As a caretaker of history, drilling a hole that doesn't belong, in a 1911 anything would be messing it up.
Advice: fit a spacer plate between the manifold and carb and put your primer there and preserve any remaining originality of the intake system for the next owner.
Answer to your question: Something different. Check your Machinery's Handbook.
Scott Conger

Tyranny under the guise of law is still Tyranny

NH Full Flow Float Valves
Obsolete carburetor parts manufactured


Topic author
Robert Bente
Posts: 74
Joined: Sun Jan 06, 2019 12:19 pm
First Name: Robert
Last Name: Bente
* REQUIRED* Type and Year of Model Ts owned: 1916 runabout, 1921 touring, 1915 touring
Location: Redding, Ca.
MTFCA Number: 49948

Re: Drill and tap

Post by Robert Bente » Mon Apr 08, 2019 10:34 pm

Scott, I thought about that, not sure how to go about a spacer plate. If you can advise how to do this I would be beyond grateful. Pictures help me me.
BTY, I just returned from 2 weeks working out of Sheridan.
r/s Bob


Loftfield
Posts: 223
Joined: Sun Jan 06, 2019 1:26 pm
First Name: Thomas
Last Name: Loftfield
* REQUIRED* Type and Year of Model Ts owned: 1912 Touring, 1912 Express Pick-up
Location: Brevard, NC, USA
MTFCA Number: 49876
MTFCI Number: 24725

Re: Drill and tap

Post by Loftfield » Tue Apr 09, 2019 8:03 am

I just had to have the flange of the cast aluminium intake manifold on my 1910 Buick welded. The item is exactly what you have. Before you drill a hole to ruin a scarce piece of history, please contact me and we can exchange intake manifolds. Since mine is already "ruined" by the welding, drilling a hole in it would be no curse and I would LOVE to have a proper manifold. Contact me however you can.

Thomas Loftfield
LOFTFJELD@GMAIL.COM
828-243-4569
Brevard, NC


Scott_Conger
Posts: 6431
Joined: Sun Jan 06, 2019 11:18 am
First Name: Scott
Last Name: Conger
* REQUIRED* Type and Year of Model Ts owned: '13, '15, '19, '23
Location: Clark, WY
Board Member Since: 2005

Re: Drill and tap

Post by Scott_Conger » Tue Apr 09, 2019 10:10 am

Bob

First, I would go to 1/8 NPT fitting...much smaller. Second, I'd find a piece of 1/2 or 5/8 aluminum plate and trace the intake flange shape onto it. Cut out the shape and finish on an endless belt sander or machine with a mill. Third, overlay a gasket on the blank and create the manifold hole and two mounting holes. Fourth, place the new flange in milling machine or drill press vice and drill into it with proper tap drill and then hold the tap in the chuck and start the tap by hand using the machine to keep it square.

When you're done, you will have a spacer plate between the carb and manifold (new gaskets on both sides) which is fitted with a 1/8 NPt fitting that should be able to accept whatever additional plumbing you intend to put on it.

Myself, I would not use a NPT fitting at all. I would use a much thinner aluminum blank and press in a 1/4" pipe and work my fittings off of that. Done well, it would barely be noticable.

BTW, I think Sheridan has a neat downtown that has held up well. Lots of early neon signage...not so crazy about the rest of it, though...too big. I really like Buffalo, just south of there. Always enjoy staying at the Occidental Hotel when in Buffalo, and having breakfast at the "Busy Bee" next door. Fans of "Longmire" will understand the reference.

FWIW
Scott Conger

Tyranny under the guise of law is still Tyranny

NH Full Flow Float Valves
Obsolete carburetor parts manufactured

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