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This thread is in response to another thread called "Fixing Up Turret Tooling " that has many facets of turning capability, but one of the needs is making screws of various forms.
I built a form of box tool many years ago when I was faced with making many many screws, both square and hex head and in a manual lathe . A totally boring job.
A good friend in Indiana showed me his work and I improved on it and the result is the following tool which I will describe here.
I was going to write an article for Home Shop Machinist Magazine, our loyal supporters for this website, but never got a round to it.
So maybe with these pictures it can help someone as I describe the tool. the tool will make screws in seconds and be very repeatable
Basically, The tool can be mounted in either a tailstock or an Aloris Style Tool Post
The advantage of the tailstock is that the screw can be parted off immediately
The advantage of the Aloris mount is more rigidity , which is needed for larger diameter screws < .25
A typical run takes maybe 10-15 seconds for a completed hex or square head screw
So first the pictures, then the process
The work piece diameter is unique to the Work Bushing , The bushing can accept round, hex, or square stock as long as there is a sliding fit !
I make extra bushings with a 1/8 hole and then drill them out as needed to match the diagonal size for hex/square stock, or the Diameter (+.0005) for round stock.
The Bushing turns freely in the Box Tool Body and is retained by a set screw from coming out when the work is retracted.
The Tool Bit is always on Center where the Cut Edge matches the work piece center-line.
For Thread Diameter settings, I introduce a Depth Mike into a hole that exactly matches the HSS tool cutting point
and I record the setting for future use. So you loosen the tool clamp and slide the tool into the depth mike (preset) and clamp and done !
For first run stock do a rough setting, make a cut and measure and that tells you how much more to set the mike.
No fiddling with tool clamping over and over
Here are some bushings of various sizes . Note the bushings have a relief grove that the retaining set screw rides in ( but does not clamp !)
Note the bushing for square stock to be used in a 3 jaw chuck
Note the square stock in a Square broached bushing, which I found is not needed ( nice, but not necessary) If the raw material ( I use Ground Key Stock ) is
precise, the stock will be supported by a round hole as long as it is on the snug side , and eliminates making broached bushings.
What you see above is what I call "Sticks" . If I decide to not part-off in the lathe and need large quantities, I use multiple sticks ( start at 6") and do both ends
as seen here above and then a second operation is needed later.
below are my Die Holders , a generous size and knurled for gripping when needed
The Die holder is bored on one side for a running fit on the Box Tool Body "Boss' and the other side is made for whatever size dies you use.
The two here are for 5/8 and 1" I believe
The operation goes like this:
Extend the work piece from the chuck and start the lathe. if you intend to part off, calculate the exposure to keep the stock close to the chuck
Feed in the Box Tool- I actually slide the tailstock on the ways for smaller screws so my cutoff tool never changes X location .
Anyway, feed the Box tool in until the stop prevents movement .
Immediately retract the Box tool to about 2 inches of clearance and mount the die holder in the Bossl WITHOUT stopping the lathe
and then feed the Box tool back into the work, the die will start turning when it starts its cut, and you hold the knurl as needed to thread
Since the Boss is about 1/4" deep, it will start the thread straight and you can hold it until it is threaded and have your hand on the F/R Switch and move the Boxtoll back and go into reverse to un-thread the die . Part if needed. For small screws, I do not recommend a fast spindle speed as the die is unsupported
I'll post another picture of the die mounted to the tool next
Rich
PS
For Tailstock mounting, I recommend a very rigid clamp on the depth setting and you could add a lock nut as well
The clamp I have is very strong in that respect.
I built a form of box tool many years ago when I was faced with making many many screws, both square and hex head and in a manual lathe . A totally boring job.
A good friend in Indiana showed me his work and I improved on it and the result is the following tool which I will describe here.
I was going to write an article for Home Shop Machinist Magazine, our loyal supporters for this website, but never got a round to it.
So maybe with these pictures it can help someone as I describe the tool. the tool will make screws in seconds and be very repeatable
Basically, The tool can be mounted in either a tailstock or an Aloris Style Tool Post
The advantage of the tailstock is that the screw can be parted off immediately
The advantage of the Aloris mount is more rigidity , which is needed for larger diameter screws < .25
A typical run takes maybe 10-15 seconds for a completed hex or square head screw
So first the pictures, then the process
The work piece diameter is unique to the Work Bushing , The bushing can accept round, hex, or square stock as long as there is a sliding fit !
I make extra bushings with a 1/8 hole and then drill them out as needed to match the diagonal size for hex/square stock, or the Diameter (+.0005) for round stock.
The Bushing turns freely in the Box Tool Body and is retained by a set screw from coming out when the work is retracted.
The Tool Bit is always on Center where the Cut Edge matches the work piece center-line.
For Thread Diameter settings, I introduce a Depth Mike into a hole that exactly matches the HSS tool cutting point
and I record the setting for future use. So you loosen the tool clamp and slide the tool into the depth mike (preset) and clamp and done !
For first run stock do a rough setting, make a cut and measure and that tells you how much more to set the mike.
No fiddling with tool clamping over and over
Here are some bushings of various sizes . Note the bushings have a relief grove that the retaining set screw rides in ( but does not clamp !)
Note the bushing for square stock to be used in a 3 jaw chuck
Note the square stock in a Square broached bushing, which I found is not needed ( nice, but not necessary) If the raw material ( I use Ground Key Stock ) is
precise, the stock will be supported by a round hole as long as it is on the snug side , and eliminates making broached bushings.
What you see above is what I call "Sticks" . If I decide to not part-off in the lathe and need large quantities, I use multiple sticks ( start at 6") and do both ends
as seen here above and then a second operation is needed later.
below are my Die Holders , a generous size and knurled for gripping when needed
The Die holder is bored on one side for a running fit on the Box Tool Body "Boss' and the other side is made for whatever size dies you use.
The two here are for 5/8 and 1" I believe
The operation goes like this:
Extend the work piece from the chuck and start the lathe. if you intend to part off, calculate the exposure to keep the stock close to the chuck
Feed in the Box Tool- I actually slide the tailstock on the ways for smaller screws so my cutoff tool never changes X location .
Anyway, feed the Box tool in until the stop prevents movement .
Immediately retract the Box tool to about 2 inches of clearance and mount the die holder in the Bossl WITHOUT stopping the lathe
and then feed the Box tool back into the work, the die will start turning when it starts its cut, and you hold the knurl as needed to thread
Since the Boss is about 1/4" deep, it will start the thread straight and you can hold it until it is threaded and have your hand on the F/R Switch and move the Boxtoll back and go into reverse to un-thread the die . Part if needed. For small screws, I do not recommend a fast spindle speed as the die is unsupported
I'll post another picture of the die mounted to the tool next
Rich
PS
For Tailstock mounting, I recommend a very rigid clamp on the depth setting and you could add a lock nut as well
The clamp I have is very strong in that respect.
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