How to Use Mill to make a Small Tool

dsanford1946

I have very little experience in using my Unimat so I am requesting some help.?

I need help in making a tool to remove parts from a Model T Stewart NH carburetor.? This tool can be made from a 1/2" bolt (or hex bar stock) and needs to have a 1/4" hole drilled through the center for a centering rod.? That part I think I can handle.? The end opposite the hex head needs to have a flat ridge down the middle of the bolt about 1/8" wide.? This would be like a large, flat bladed screwdriver.? The part I need to remove is made of brass. Some of these have been in the carburetor body (cast iron) for over 90 years and can be hard to unscrew.? They can be easily damages without the proper tool.

I need to make it look similar to the tool in the center of this picture.?

Any help on how to set up the Unimat to make this will be appreciated.

#57144

? ? ?Have you tried heating carb in a toaster oven?? I have had some success heating carbs for 30 minutes @ 250-300 degrees to break free stubborn brass parts.

Show quoted text

On Mon, Nov 15, 2021 at 1:49 PM dsanford1946 via <dd.sanford=[email protected]> wrote:

I have very little experience in using my Unimat so I am requesting some help.?

I need help in making a tool to remove parts from a Model T Stewart NH carburetor.? This tool can be made from a 1/2" bolt (or hex bar stock) and needs to have a 1/4" hole drilled through the center for a centering rod.? That part I think I can handle.? The end opposite the hex head needs to have a flat ridge down the middle of the bolt about 1/8" wide.? This would be like a large, flat bladed screwdriver.? The part I need to remove is made of brass. Some of these have been in the carburetor body (cast iron) for over 90 years and can be hard to unscrew.? They can be easily damages without the proper tool.
I need to make it look similar to the tool in the center of this picture.?

Any help on how to set up the Unimat to make this will be appreciated.

#57145

You going to be doing a bunch of these, or just one? If the tool width is 1/8", you could slot it, and use a piece of keystock, or if it needs to be longer, a piece of 1/8" plate sawn and filed to shape, and sweated or riveted in place. If you're doing a lot of them, spending more time making the correct tools makes a lot of sense. If it's a one off, you could just make a brass hollow-ground screwdriver, ground or milled to fit the slot you need to engage.

MIght also look at Wheeler gunsmithing tools: https://www.wheelertools.com/gunsmithing-tools/wrenches-and-screwdrivers/space-saver-screwdriver-set/664507.html#start=1 modifying one of the bits in the kit I linked might do what you need to do. I have that set, and a FAT Wrench (torque screwdriver) with a larger hollow ground insert: https://www.wheelertools.com/gunsmithing-tools/wrenches-and-screwdrivers/f.a.t.-wrench-with-10-bit-set/553556.html#start=1

Or you might want to check with the Chapman Tool Co. https://chapmanmfg.com/collections/individual-parts/products/slotted-insert-bits They have just about any bit you could imagine...

There are probably lots of ways to skin that particular cat.

Bill in OKC

William R. Meyers, MSgt, USAF(Ret.)

A human being should be able to change a diaper, plan an invasion,
butcher a hog, conn a ship, design a building, write a sonnet, balance
accounts, build a wall, set a bone, comfort the dying, take orders,
give orders, cooperate, act alone, solve equations, analyze a new
problem, pitch manure, program a computer, cook a tasty meal, fight
efficiently, die gallantly. Specialization is for insects.
LAZARUS LONG (Robert A. Heinlein)

On Monday, November 15, 2021, 12:49:50 PM CST, dsanford1946 via groups.io <dd.sanford@...> wrote:

I have very little experience in using my Unimat so I am requesting some help.?

I need help in making a tool to remove parts from a Model T Stewart NH carburetor.? This tool can be made from a 1/2" bolt (or hex bar stock) and needs to have a 1/4" hole drilled through the center for a centering rod.? That part I think I can handle.? The end opposite the hex head needs to have a flat ridge down the middle of the bolt about 1/8" wide.? This would be like a large, flat bladed screwdriver.? The part I need to remove is made of brass. Some of these have been in the carburetor body (cast iron) for over 90 years and can be hard to unscrew.? They can be easily damages without the proper tool.

I need to make it look similar to the tool in the center of this picture.?

Any help on how to set up the Unimat to make this will be appreciated.

#57147

BTW, that middle tool looks an awful lot like a self-holding screwdriver I used at work, a couple of years ago. Mine was sized for 3/16" round head machine screws, so only about 1/16" or less in thickness. This one is similar to what I had, but too small for your use: https://www.amazon.com/Stanley-Proto-J9866-Slotted-Phillips/dp/B002C64SKS The cap at the end is spring loaded, you twist it to put the screw on it, and let go to hold it. Then start the screw, and drive it the rest of the way with a common screwdriver. Not finding anything bigger.

Bill in OKC

William R. Meyers, MSgt, USAF(Ret.)

A human being should be able to change a diaper, plan an invasion,
butcher a hog, conn a ship, design a building, write a sonnet, balance
accounts, build a wall, set a bone, comfort the dying, take orders,
give orders, cooperate, act alone, solve equations, analyze a new
problem, pitch manure, program a computer, cook a tasty meal, fight
efficiently, die gallantly. Specialization is for insects.
LAZARUS LONG (Robert A. Heinlein)

On Monday, November 15, 2021, 01:12:15 PM CST, Bill in OKC too via groups.io <wmrmeyers@...> wrote:

You going to be doing a bunch of these, or just one? If the tool width is 1/8", you could slot it, and use a piece of keystock, or if it needs to be longer, a piece of 1/8" plate sawn and filed to shape, and sweated or riveted in place. If you're doing a lot of them, spending more time making the correct tools makes a lot of sense. If it's a one off, you could just make a brass hollow-ground screwdriver, ground or milled to fit the slot you need to engage.

MIght also look at Wheeler gunsmithing tools: https://www.wheelertools.com/gunsmithing-tools/wrenches-and-screwdrivers/space-saver-screwdriver-set/664507.html#start=1 modifying one of the bits in the kit I linked might do what you need to do. I have that set, and a FAT Wrench (torque screwdriver) with a larger hollow ground insert: https://www.wheelertools.com/gunsmithing-tools/wrenches-and-screwdrivers/f.a.t.-wrench-with-10-bit-set/553556.html#start=1

Or you might want to check with the Chapman Tool Co. https://chapmanmfg.com/collections/individual-parts/products/slotted-insert-bits They have just about any bit you could imagine...

There are probably lots of ways to skin that particular cat.

Bill in OKC

William R. Meyers, MSgt, USAF(Ret.)

A human being should be able to change a diaper, plan an invasion,
butcher a hog, conn a ship, design a building, write a sonnet, balance
accounts, build a wall, set a bone, comfort the dying, take orders,
give orders, cooperate, act alone, solve equations, analyze a new
problem, pitch manure, program a computer, cook a tasty meal, fight
efficiently, die gallantly. Specialization is for insects.
LAZARUS LONG (Robert A. Heinlein)

On Monday, November 15, 2021, 12:49:50 PM CST, dsanford1946 via groups.io <dd.sanford@...> wrote:

I have very little experience in using my Unimat so I am requesting some help.?

I need help in making a tool to remove parts from a Model T Stewart NH carburetor.? This tool can be made from a 1/2" bolt (or hex bar stock) and needs to have a 1/4" hole drilled through the center for a centering rod.? That part I think I can handle.? The end opposite the hex head needs to have a flat ridge down the middle of the bolt about 1/8" wide.? This would be like a large, flat bladed screwdriver.? The part I need to remove is made of brass. Some of these have been in the carburetor body (cast iron) for over 90 years and can be hard to unscrew.? They can be easily damages without the proper tool.

I need to make it look similar to the tool in the center of this picture.?

Any help on how to set up the Unimat to make this will be appreciated.

#57149

For my first attempt I would put some hex bar in the three jaw chuck - I would buy a bit of hex bar since I would expect to have more then one try. Use a tough or hardenable, steel, and expect to take very fine cuts with a very sharp tool. You could use a bigger bar of silver steel (drill rod) and file spanner flats on it later, and it could hardened & tempered. It can also be annealed if you nead to make small adjustments to the shape, and then hardened again. If I was confident the screws were not going to put up too much of a fight I would consider making the thing from hard brass. do you have any idea what steel the ones in the photo are made from?

Turn down the working end to the diameter and length required to make the complicated features. Leave as much as possible as solid as possible while doing the fiddly work. Centre drill the end and use a live centre to get more rigidity. If the steel is tough it might be worth revolving it slowly and using something like a mini-grinder to take the hexagon down to something near circular.

Finish turn the very end to the correct diameter and face off as much as the live centre allows. Turn a very shallow shoulder to show the depth of the blade part. Drill the centre hole to the diameter required.

Take the job off the lathe with the chuck still attached - that way when you put it back again it will still run true.

File the blade part down to the shoulder and to the width needed, taking care to get everything square and parallel. This may need more than one go, and will need a good quality file with a proper safety edge. Many files have the safety edge ground? before the teeth on the other faces are formed. They then throw up cutting corners on the safety edge which mess up jobs. Run a stone down the safety edge until those corners are gone - then it will file into tight corners without messing up the job.

Put it back in the lathe and turn down the hexagon to the length and diameter required.to clear for the cylindrical portion.

Turn up a bit of round bar to fit the central hole and make it a decent press fit. If you can drill through from the other end you will be able to knock the pin out later if it needs changing.

If you used? hardenable steel, harden and temper it to whatever is recommended for screwdrivers.

I don't know how much sense this makes to you, but maybe it helps to give you ideas.

#57152

This is essentially identical to a spanner screw, one type of
tamper-proof screw. If you can make do without the central locating pin
you could just pick up a set of tamper-proof bits for a magnetic handle.
Klein tools makes a nice set with all the most common security bit styles.

Show quoted text

On 11/15/21 1:49 PM, dsanford1946 via groups.io wrote:

I have very little experience in using my Unimat so I am requesting some
help.

I need help in making a tool to remove parts from a Model T Stewart NH
carburetor.? This tool can be made from a 1/2" bolt (or hex bar stock)
and needs to have a 1/4" hole drilled through the center for a centering
rod.? That part I think I can handle.? The end opposite the hex head
needs to have a flat ridge down the middle of the bolt about 1/8" wide.
This would be like a large, flat bladed screwdriver.? The part I need to
remove is made of brass. Some of these have been in the carburetor body
(cast iron) for over 90 years and can be hard to unscrew.? They can be
easily damages without the proper tool.
I need to make it look similar to the tool in the center of this picture.

Any help on how to set up the Unimat to make this will be appreciated.

--
Elliot Nesterman
elliot@...
www.ajoure.net

"The finest jewel cannot disguise a flawed character."

#57153

I have a couple versions of that set, not Klein, and they are good for many things, but none of them will work on a 1/8" wide screwdriver slot. Is why I suggested Chapman or Wheeler tools. They do make screwdriver bits at least closer to that size, and Chapman sells individual bits, which I'm not seeing on the Wheeler site.?

Also I have a partial Chapman set my Dad gave me several decades ago, and despite spending some time submerged in water for a time, they mostly still work. Good stuff!

Bill in OKC

William R. Meyers, MSgt, USAF(Ret.)

A human being should be able to change a diaper, plan an invasion,
butcher a hog, conn a ship, design a building, write a sonnet, balance
accounts, build a wall, set a bone, comfort the dying, take orders,
give orders, cooperate, act alone, solve equations, analyze a new
problem, pitch manure, program a computer, cook a tasty meal, fight
efficiently, die gallantly. Specialization is for insects.
LAZARUS LONG (Robert A. Heinlein)

On Monday, November 15, 2021, 05:05:59 PM CST, Elliot Nesterman <elliot@...> wrote:

This is essentially identical to a spanner screw, one type of
tamper-proof screw. If you can make do without the central locating pin
you could just pick up a set of tamper-proof bits for a magnetic handle.
Klein tools makes a nice set with all the most common security bit styles.

Show quoted text

On 11/15/21 1:49 PM, dsanford1946 via groups.io wrote:

I have very little experience in using my Unimat so I am requesting some
help.

I need help in making a tool to remove parts from a Model T Stewart NH
carburetor.? This tool can be made from a 1/2" bolt (or hex bar stock)
and needs to have a 1/4" hole drilled through the center for a centering
rod.? That part I think I can handle.? The end opposite the hex head
needs to have a flat ridge down the middle of the bolt about 1/8" wide.
This would be like a large, flat bladed screwdriver.? The part I need to
remove is made of brass. Some of these have been in the carburetor body
(cast iron) for over 90 years and can be hard to unscrew.? They can be
easily damages without the proper tool.
I need to make it look similar to the tool in the center of this picture.

Any help on how to set up the Unimat to make this will be appreciated.

--
Elliot Nesterman
elliot@...
www.ajoure.net

"The finest jewel cannot disguise a flawed character."

#57154

Another suggestion to help free the brass parts.

Instead of heating try cooling or cycle the heating & cooling.

In the past I have wrapped item & put them in the freezer for a few days.
Items that wouldn't be damaged by water or distorted by water freezing
have been sat in water & frozen in a block of ice, sometimes water added
in layers, then left for a few days.
Doing that ensured it was fully frozen.

I have used the cans of spray freeze from electronic suppliers for
smaller & tiny items.

If the first heating or freezing doesn't work then try cycling it a few
times.

Regards,
Brian.

Show quoted text

On 16-November-2021 4:56 am, Jeffrey Kropp wrote:

? ? ?Have you tried heating carb in a toaster oven?? I have had some
success heating carbs for 30 minutes @ 250-300 degrees to break free
stubborn brass parts.

#57155

You may want to look for a tool called a drag link. They are essentially large flat screwdriver blades on a socket.?--

Thanks,

Dustin Gebhardt

dsanford1946

#57156

Thanks for all of the responses.? Some very good ideas.? I will post some more later on the part I need to remove.

Where can I find more information on setting up the mill and then how to use it?? I need to go back to the basics on the mill.? Is there a "library" of instructions on this site?

#57157

I'd look through all of the files, but this is a really good place to start: /g/Unimat/files/Books%20-%20Tingey,%20etc.

Bill in OKC

William R. Meyers, MSgt, USAF(Ret.)

A human being should be able to change a diaper, plan an invasion,
butcher a hog, conn a ship, design a building, write a sonnet, balance
accounts, build a wall, set a bone, comfort the dying, take orders,
give orders, cooperate, act alone, solve equations, analyze a new
problem, pitch manure, program a computer, cook a tasty meal, fight
efficiently, die gallantly. Specialization is for insects.
LAZARUS LONG (Robert A. Heinlein)

On Tuesday, November 16, 2021, 10:46:33 AM CST, dsanford1946 via groups.io <dd.sanford@...> wrote:

Thanks for all of the responses.? Some very good ideas.? I will post some more later on the part I need to remove.

Where can I find more information on setting up the mill and then how to use it?? I need to go back to the basics on the mill.? Is there a "library" of instructions on this site?

#57159

If all else fails, you might have to resort to the time honored method of accurately drilling the brass orifice out and running the correct size tap into the hole. Then make a new orrifice.

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How to Use Mill to make a Small Tool