Simple things are never easy

[Bernd]

Seems like the simplest requests are sometimes the most tedious jobs. The local hot rod boys know they have a machinist amongst them and he can make almost anything, ….well almost anything. :

Now these guys know their cars and what makes them tick, but when it gets to the finer points of knowing screw sizes and such they fall a bit short. So I go and look at what he wants and it goes something like this.

"See that large hole in the head?"
"Ya".
"Well I need to have an adapter made so I can bolt the alternator to the head." "Can you do that?"
"Yup, I can do that."

So I get handed a large bolt that fits the hole threads and the spacer and bolt that originally held on the alternator. No problem right? Wrong. Once I get home I check the size of the large thread, 5/8"-11 thread. What model engineer has that large a die at home? Not me. Ok, so I have to buy one. Next I need to find the size of the original bolt that held the alternator to the head. Looks like 1/2-13. I hold up a 1/2-13 tap next to the bolt. Doesn't seem quite right. ??? Threads don't match. Could this be a metric bolt. Can't be. This is an older car. I get out the thread gage and start checking threads. It's definitely courser than 13 per inch. 12, nope, 11, yup. 11. What the heck is that. I look at the thread chart and there it is-7/16-11. Ok, who has a 7/16-11 tap in there shop? I don't. I guess I need to buy one of those to. Next I need to find some stock to make this from. Of course I don't have what I want to make it from so a trip to the city to the metal supplier. I get there only to find the place has closed down. ??? I see this is not going to be a good day. So it's over to the other place that deals only in non-ferrous metals. I figure I'll make the part out of 1" hex aluminum instead of steel like I originally wanted to do. I get there and browse around looking for some hex stock. I get asked if I need help.

"Sure, I need some 1" hex."
"All I have is 12' and they can't cut it"
"Well that length won't quite fit in my VW Beetle. I'll take the 1" round 6' long piece instead."

So home I go and stop by the hot rod guy and tell him I can make the adapter but it will be a while before I get the taps and dies I need to make the part. I tell him it'll probably be about 2 weeks since I'm also going to be out of town for a week and a half. That's not good for him since he needs it ASAP. I tell him I'll make the part minus threads if he can find somebody to tap and thread the part. That's fine by him.

Below is a pic of the original bolt and spacer used to fasten the alternator in it's place

Here's the adapter without the threads.

After I made the first part it came to me that I could single point the 5/8-11. He would just have to have the hole tapped. So I made a second part and single pointed the thread. The I got real brave and decided I could probably single point the 7/16-11. I had bought a thread kit a few years back for doing inside threads. After I got the kit I found I couldn't do the threads because the tool was designed to do small or fine pitch threads. So I got that out and set it up and single pointed the 7/16-11 inside threads.

Below are pics that I really did this. The first one shows the part in the chuck jaws and the original bolt. It's to show how long the thread is on the bolt.

Here is the bolt threaded into the hole.

This is a pic of the threading insert. I've laid a pencil next to it for size comparison.

This is the kit that I had purchased.

And this is how it will look all put together, but without the alternator.

So all in all it didn't turn out to be to bad a day after all. I'm amazed that I can still single point threads, both outside and inside after all these years of not having done that.

Bernd

 

[Brass_Machine]

Hey BernD.

Nice job there! I am still not brave enough to turn threads on my lathe yet :-\

Eric

 

[Powder keg]

Threads are easy Eric) I'll try and do a quick tutorial soon. I have a great chart also. an older gentleman gave it to me. I'll scan it and put it up here to. I need to figure out the camera thing first.

Wes

 

[Bernd]

Thanks Eric.

Didn't anybody catch the 7/16"-11 threads statement. ??? Boy did I screw up. :wall: I meant it to be 7/16"-14. The bigger one is 5/8"-11.

I guess it wasn't such a good day after all. Oh well.

Bernd

 

[rake60]

Nice work Bernd!

I actually like threading.
I'm NOT saying it always comes out perfect on the first attempt,
but I do like doing single point threading.

Rick

 

[Bernd]

Nice work Bernd!

Thanks Rick.

I actually like threading.
I'm NOT saying it always comes out perfect on the first attempt,
but I do like doing single point threading.

Rick

I've done a little bit of OD threading in the past year, but never tried ID threading in a long time. (High school days, almost 40 years ago?).

I figured what the heck might as well try it. I've got the tool and it's a piece of aluminum what could go wrong. The hard part was lining that little carbide threading tool perpendicular to the work. Can't say NASA would approve but it worked.

Might get brave and throw all my taps and dies away and just single point, NOT. :big: It is satisfying when it comes out OK.

Bernd

 

[chuck foster]

i did allot of threading when i was making the boat propeller shafts, i liked doing it but some times it was nerve racking.
the boss would walk by and let me know that i was working on a piece of stainless that cost more than i made in a year!!!

my thought were "thanks boss..........just turn up the pressure some more"

chuck

 

[rake60]

i did allot of threading when i was making the boat propeller shafts, i liked doing it but some times it was nerve racking.
the boss would walk by and let me know that i was working on a piece of stainless that cost more than i made in a year!!!

my thought were "thanks boss..........just turn up the pressure some more"

chuck

Now that brings back memories Chuck!

Back when I was running the the big vertical boring mill at work we made a rather large
brass part with an internal thread. The casting was 132" ID, 138" OD and 36" long.
I was told at least 5 times before my shift began that that casting cost $47,000

So what, they make new castings every day.
All I was concerned with was what was going on the the point of the tool.
$6 worth of scrap swarf on every pass.
The finished part turned out fine and passed the in house and customers inspections.

It was just another thread cut one pass at time.

Rick