Tapping puzzler

I'm making a brake line tee for a guy , and I'm having trouble getting an acceptable fit . The compression nut reads 9.85 mm x 1mm pitch . The tap I bought measures 10.10 ... and the nut is way too loose in the threads . I'm wondering if this auto parts store tap is oversize ... might be OK for a bolt thru a bracket or something , but I'm not using it for this job . Is there a chart somewhere that has size data for taps by fit class ?

Reply to
Terry Coombs
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Flare fittings should be used for brakes, not compression.

MikeB

Reply to
BQ340

For a brake line its typically a double flare fitting. Also, amazingly enough if you "over" tighten them they are more likely to leak then if you under tighten them.

Reply to
Bob La Londe

Yup , double flare . Looks like a little button on the end of the tube . Bob , you wouldn't happen to know the included angle of that seat ? Looks like a

135 deg bit would work , 118 is too steep , it only contacts on the outside edge . I can grind a bit to any angle in between , thanks to my neighbor .
Reply to
Terry Coombs

Do yourself and the guy and just BUY the proper brake line tee. Standard Weatherhead fittings are readilly available.

Reply to
clare

Wasn't my idea to begin with ... this is for my neighbor , done a fair bit of work for him already . I do want this done right .

Reply to
Terry Coombs

Correct

Reply to
Gunner Asch

Terry Coombs laid this down on his screen :

Get a Professonal made part. If you make it and fails you will never hear the end of it.

I had an amature job fail on a brake line 400 miles into the desert north east of Alice Springs a long time ago. That was no fun. :/ Fortunatly there is very very little traffic out there. And I had to make a new flare with a Phillips screwdriver to get home!!! It had been made by the previous owner,before I bought the vehicle. :-Z

Reply to
John G

Nope, that's a compression fitting.

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25 seconds into the video, you'll see the brass sleeve/button.

Terry, I'm not sure you have the proper picture on the task. Here's the picture for a double flared tube. The seat must be a convex shape, not concave, so the bit will have to have a cone rather than a point.

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And the nut will have an inner flare to the tip to mate the bell of the tube.

When I was wrenching, I only saw the Japanese style, not the Euro.

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Which is the one you're working on?

Reply to
Larry Jaques

The ISO/DIN or bubble flare in your link below . The vehicle in question is a Ford Mustang , late model . He's putting a different master cylinder on because he's using a rear axle with disc brakes , and I'm also making an adapter plate to mount that .

Reply to
Terry Coombs

The most likely cause of the problem is that it might not be a metric fitting but a more common 3/8-24 fitting. The 3/8 has a smaller major diameter but is so close to the metric that the

3/8-24 will thread into a 10-1 (not suggested) but the 10-1 will not fit into a 3/8-24 hole.

Paul K. Dickman

Reply to
Paul K. Dickman

Nope , this fitting will not thread into a 3/8-24 hole - though some of the lines he's got must , as the proportioning valve he brought down has 2 holes threaded for it - but those also have the conical flare seat , not the concave "bubble" flare . The nut that goes in this fitting

Reply to
Terry Coombs

You are working on a "critical safety system". "doing it right" generally involves using parts made and certified for the purpose..

Buy the correct brake part for thr job. This coming from a licenced auto mechanic and a machinist.

Reply to
clare

All the parts for the disk brake conversion are available from Ford and the aftermarket as that setup was used on the Ford Explorer. As well as on the Mustang Cobra. Being a Ford it will be a standard double flare - NOT a bubble flare - unless he is using brake parts from a Euro Ford, perhaps.

Reply to
clare

The OD of normal taps is always larger than the nominal thread size. Look at the thread tables in Machinery's Handbook and you'll see that the major diameter of internal threads is the nominal diameter with a plus tolerance.

10.11 mm OD for an M10x1 tap sounds about right.
Reply to
Ned Simmons

Reply to
John B.

I think Clare has the best idea. Just buy the tee. Much safer/easier.

Reply to
Larry Jaques

Right. Bag o' worms, wot?

Reply to
Larry Jaques

Mabee he's putting non-Ford brakes on it - like Jag?? Real easy to fix that too. Put a flare adapter fitting on the Euro part and use SAE double flare lines trhoughout. And BUY the proper part. You cannot afford to make them at the price they sell for.

Just DO NOT screw around with brakes without knowing EXACTLY what you are doing.

Reply to
clare

And what you want to do to check the diameter of threads is to measure the *pitch* diameter -- which is usually done on male threads with three wires of selected diameter down in the Vs -- two on one side and one on the other. This measures the surfaces which should mate.

The drawing below should be viewed with a fixed pitch font like Courier. Any of the variable pitch fonts will cause the later (right-most) parts to fall out of alignment on your screen.

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Reply to
DoN. Nichols

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