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Inside threading 3/4 Sched 40 Pipe

Susquatch

Susquatch

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This thread is to all about document my method of inside threading.

The project is to make pin extensions for 3pt hitch pins so that they can be mounted to a moveable cart to optimize space for equipment storage in my barn.

The idea for this thread originally came from an offer to help @David_R8 make a spindle adapter for his new lathe. The discussion in that thread can be found here:

Post in thread 'Faceplate on a chuck?' https://canadianhobbymetalworkers.com/threads/faceplate-on-a-chuck.7977/post-117756

I will post project photos shortly.
 
Just a word of warning - pipe isn't generally round, and will have a high (and hard) inside weld bead. Need to allow for this in your design.
 
whydontu said:
Just a word of warning - pipe isn't generally round, and will have a high (and hard) inside weld bead. Need to allow for this in your design.
Click to expand...

Of course! That's half the fun!

I had planned to make that invisible. But now you spoiled it!

I chose schedule 40 pipe because it's cheap and "good enough" not because it's perfect for the job.

I use Schedule 40 pipe to make tools for lots of things. Just a few examples :

1. A pool cover spring tool to put the springs on and off of the anchors.

2. Rollers for moving machinery

3. Replacement pump and spigot handles for Hydraulic Bottle Jack's. I genuinely hate the bars that come with those Jack's.

4. A sharp gouge for cleaning out drain pipe.

5. Assorted sizes to fit chuck T-Wrenches (never to tighten - only to loosen).

6. Assorted sizes to fit big Johnson Bars to grunt down big fasteners. Commonly called a Cheater.

7. Tree, tent, tarp, post, pole, and whatever support anchors.
 
whydontu said:
45 years selling pipe, valves, and fittings. Sch40 for everything. Only thing more useful than Sch40 pipe is Unistrut.
Click to expand...

More useful than Schedule 40 eh.......:oops:

I know what Unistrut is but I've never used it. Tell me about how you use Unistrut....... And please give me a few examples......
 
Susquatch said:
More useful than Schedule 40 eh.......:oops:

I know what Unistrut is but I've never used it. Tell me about how you use Unistrut....... And please give me a few examples......
Click to expand...

Carts, work benches, frames, overhead trolleys

With those little spring loaded nuts and all the various corner pieces/plates/trolleys your imagination is the limit with that stuff
 
Susquatch said:
Can't even get my own thread off the ground and already I'm off on a new tangent....... Krikey.
Click to expand...
Think of unistrut as hollow steel 2x2s. Anything you can build with 2xX lumber you can build with unistrut, except unistrut doesn’t warp, has 100x the load capacity, and comes in very straight lengths. Bolts together, or weld it. Remember how the bolt holes in Meccano didn't always line up where you wanted them? Unistrut is infinitely adjustable for fastener placement.
 
Ok, so back on topic...... LOL!

Here is the assignment. Make a cart like this one to hold my Ripper Plow. This one is for my sprayer. It's just a plain old skid with wheels on struts for balance and height. I put my sprayer on it and roll it away to its spot in the barn. When I need to use the sprayer, I roll it out to the door, hook up the sprayer to my tractor, lift it off the cart, and off I go! At some point, I will add trays inside and under it for sprayer accessories and Kit.

20230613_175653.jpg


The Ripper Plow is heavy and awkward. A skid didn't work. So I made a custom cart instead.

20230613_175715.jpg


A Ripper Plow is designed to plow 3 ft down. This one is a single blade but they sell doubles and triples. Hidden behind the blade is what is called a mole ball. It is attached behind the tooth with a chain. It follows along behind the blade leaving an underground tunnel for drainage. It's not as permanent as drainage tile but for use in blue clay it works where nothing else will.

The cart has to hold the plow and the mole ball. It must also be positioned where the 3 point hitch on the tractor can hook up to the plow without the cart getting in the way.

That's where the Sch40 pipe comes into the picture.

This photo shows the idea, but the hitch pin is backward. It is temporarily positioned facing inward to facilitate building the cart.

20230613_175917.jpg


So the pin will be reversed to face the proper way like this.

20230613_180049.jpg


And a short piece of pipe will be added to the thread on the backside of the pin like this:

20230613_180058.jpg


The bushing I used does not fit properly, it's just to show what is planned.

Next up are the new Sch40 Pipe Extensions.
 
Susquatch said:
Ok, so back on topic...... LOL!

Here is the assignment. Make a cart like this one to hold my Ripper Plow. This one is for my sprayer. It's just a plain old skid with wheels on struts for balance and height. I put my sprayer on it and roll it away to its spot in the barn. When I need to use the sprayer, I roll it out to the door, hook up the sprayer to my tractor, lift it off the cart, and off I go! At some point, I will add trays inside and under it for sprayer accessories and Kit.

View attachment 35404

The Ripper Plow is heavy and awkward. A skid didn't work. So I made a custom cart instead.

View attachment 35405

A Ripper Plow is designed to plow 3 ft down. This one is a single blade but they sell doubles and triples. Hidden behind the blade is what is called a mole ball. It is attached behind the tooth with a chain. It follows along behind the blade leaving an underground tunnel for drainage. It's not as permanent as drainage tile but for use in blue clay it works where nothing else will.

The cart has to hold the plow and the mole ball. It must also be positioned where the 3 point hitch on the tractor can hook up to the plow without the cart getting in the way.

That's where the Sch40 pipe comes into the picture.

This photo shows the idea, but the hitch pin is backward. It is temporarily positioned facing inward to facilitate building the cart.

View attachment 35406

So the pin will be reversed to face the proper way like this.

View attachment 35407

And a short piece of pipe will be added to the thread on the backside of the pin like this:

View attachment 35408

The bushing I used does not fit properly, it's just to show what is planned.

Next up are the new Sch40 Pipe Extensions.
Click to expand...
If the thread is straight not tapered then single point cut them. Internal single point can be an adventure.
 
Garyt said:
If the thread is straight not tapered then single point cut them. Internal single point can be an adventure.
Click to expand...

That's the plan Gary. I've taken this particular adventure many times. It's always fun!
 
Options options options......

The ID of the cleaned up pipe is 0.840. That's on the big side of ideal for a 7/8-14 thread. Prolly only going to yield a 37% thread. The job does not justify the math, but the charts show 31% at 0.8465 and 34% at 0.8437.

Screenshot_20230615_103844_Tap And Drill Chart Calculator.jpg


Extrapolating that suggests 37%. But let's be honest, this thread doesn't have to hold goose poop. A slip fit would work if it didn't fall off. So 37% fit will work just fine for my needs.
 
Next up is still more options.

What tool to use? And which approach? It's almost a no brainer to use a regular threading tap and crank it in. BUT...... that isn't the point of this thread. Others have requested a single point thread demo so that's what this will be.

My goto threading tool Arthur Warner HSS Insert tool won't work on this job. The hole is too small. I have no idea what it's minimum thread hole is, but it's definitely bigger than this one!

20230615_104747.jpg


20230615_104824.jpg


Next up is my MESA Carbide Insert Tool.

20230615_105522.jpg


It isn't my favorite because it doesn't cut as well as sharp HSS does. But it does give the option of cutting at the front from inside out in reverse, or at the back outside in. You just choose which hole to put the screw in. Here I've chosen at the front. Time permitting, I'll do the other pin support in forward outside in.

20230615_110431.jpg


And here you can see that it fits the hole.





20230615_110457.jpg


Yes, it is on center, it just doesn't look like it. This is yet another time when a lathe tool height standard really shines. It's so easy to set tool heights with..... You don't even need the finger test with this setup. You just retract the cross slide and it either tries to tip the standard or it doesn't. This looks a bit high, but it's not. It's perfect.

20230615_111441.jpg


I confess that describing this has generated an idea. This works sooooo well for upside down tools that I am thinking I want to make something similar for right side up. A standard with a notch in it. The tool either fits UNDER it, or it doesn't! Project 42p I think.....

The other options are a purchased threading tool or a hand made tool. Although I do have a threading tool that would work, it is extremely expensive and I don't really want to use it to cut sch40 pipe.

So that leaves this handground tool.

20230615_112758.webp


Yes, believe it or not, it does have a 60 deg thread profile. It just doesn't look like it in the photo cuz I don't have a nice sharp edge grinder.

20230615_113217.jpg



Which to use?
 
That Mesa tool is very cool I don't think I've ever seen an insert like that.
 
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