Tapers on 7x16 Lathe?

MaverickNH

MaverickNH

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I’m planning a Machinist’s Hammer build that requires a handle taper. Using a 7x16 mini lathe with 2.6in of cross slide travel, it seems that one should be able to calculate the maximum taper length possible for different taper angles. What would be the maths on that? My Trig-Fu is weak…

My tailstock does have x-axis adjustment via a set screw, but I’d be worried I couldn’t realign without a lot of effort if I moved that over to make a taper.

Are there useful taper attachments for a mini lathe I should consider?

Thanks for the help!

BRET
 
You don't need trig to calculate tapers on a lathe. Taper is normally given in inches/ft. You would be turning between centers and the correct offset for the tailstock will be the desired taper times the distance between the centers in inches divided by 12 inches.

To cut a taper on a small lathe, you will need to offset the tailstock. It is extremely unlikely that you will find a taper attachment. There are some devices that fit in the Morse taper socket and shift the center so you don't have to mess with the tailstock offset.

Shifting the tailstock offset and then resetting it isn't a difficult task. It is a good practice to get familiar with. It can easily be done with the centers in place and a six inch rule. Bring the centers together to capture the rule between them . When the centers are aligned, the rule will be perpendicular to the ways. Note; the centers shouldn't have a dull or mashed point to use this method.

There are other ways to accomplish this task as well. A variation on the two collar test will align the two centers to within a fraction of a thousandth. Mount the test bar between centers and turn the two collars. when the tailstock is properly aligned, the collar diameters will be equal in diameter.
 
RJSakowski said:
You don't need trig to calculate tapers on a lathe. Taper is normally given in inches/ft. You would be turning between centers and the correct offset for the tailstock will be the desired taper times the distance between the centers in inches divided by 12 inches.

To cut a taper on a small lathe, you will need to offset the tailstock. It is extremely unlikely that you will find a taper attachment. There are some devices that fit in the Morse taper socket and shift the center so you don't have to mess with the tailstock offset.

Shifting the tailstock offset and then resetting it isn't a difficult task. It is a good practice to get familiar with. It can easily be done with the centers in place and a six inch rule. Bring the centers together to capture the rule between them . When the centers are aligned, the rule will be perpendicular to the ways. Note; the centers shouldn't have a dull or mashed point to use this method.

There are other ways to accomplish this task as well. A variation on the two collar test will align the two centers to within a fraction of a thousandth. Mount the test bar between centers and turn the two collars. when the tailstock is properly aligned, the collar diameters will be equal in diameter.
Click to expand...
Thanks for the information!

I see my mini lathe has a 3MT spindle and 2MT tailstock, so I’d just need a 3MT center as I have 2MT dead/live centers. I see Edge Technology also makes a 12.25” tailstock alignment bar true to 0.0002.
 
MaverickNH said:
Thanks for the information!

I see my mini lathe has a 3MT spindle and 2MT tailstock, so I’d just need a 3MT center as I have 2MT dead/live centers. I see Edge Technology also makes a 12.25” tailstock alignment bar true to 0.0002.
Click to expand...
You can easily make your own test bar for aligning the tailstock. Select a length suitable for your needs and center drill the ends. Turn a equal diameter one each end, as indicated by measurement with a micrometer. The tailstock doesn't have to be precisely aligned but close is better so you won't be turning a slight taper on your test sections. If you are really particular about it, you can use an iterative process: turn the initial collars and use the bar to align the tailstock then turn the collars again and you should be close to dead nuts regarding zero taper on the test bar.

To use, mount the bar between centers and mount a DTI on the cross slide. At the headstock collar, adjust for a zero reading. without moving the cross slide, move to the tailstock. The DTI will remain zeroed if the tailstock is correct.
 
RJSakowski said:
You can easily make your own test bar for aligning the tailstock. Select a length suitable for your needs and center drill the ends. Turn a equal diameter one each end, as indicated by measurement with a micrometer. The tailstock doesn't have to be precisely aligned but close is better so you won't be turning a slight taper on your test sections. If you are really particular about it, you can use an iterative process: turn the initial collars and use the bar to align the tailstock then turn the collars again and you should be close to dead nuts regarding zero taper on the test bar.

To use, mount the bar between centers and mount a DTI on the cross slide. At the headstock collar, adjust for a zero reading. without moving the cross slide, move to the tailstock. The DTI will remain zeroed if the tailstock is correct.
Click to expand...
Good idea! I can make a bar as good as my lathe is now, before adjusting the tailstock for a taper cut.
 
The lathe should have come with a mt2-3 sleeve for the headstock center. You could buy an ordinary sleeve and cut off the tang end to allow removing the center if necessary.
 
MaverickNH said:
Thanks for the information!

I see my mini lathe has a 3MT spindle and 2MT tailstock, so I’d just need a 3MT center as I have 2MT dead/live centers. I see Edge Technology also makes a 12.25” tailstock alignment bar true to 0.0002.
Click to expand...
I do not know if this comes in the moris taper you need but I'd bet you could make it work....

Set-over Centre - hemingwaykits.com

Unique projects for the small workshop owner. Please browse our Toolroom and Engine Bay for our latest project kits.
www.hemingwaykits.com
 
verbotenwhisky said:
I do not know if this comes in the moris taper you need but I'd bet you could make it work....

Set-over Centre - hemingwaykits.com

Unique projects for the small workshop owner. Please browse our Toolroom and Engine Bay for our latest project kits.
www.hemingwaykits.com
Click to expand...
A bit more costly on Amazon, but more bells & whistles.


I’m not too sure the direction of the cutting force on a workpiece when turned in a lathe - would a Morse taper hold? Or would one just let the force rotate the attachment to the stable position?
 
MaverickNH said:
A bit more costly on Amazon, but more bells & whistles.


I’m not too sure the direction of the cutting force on a workpiece when turned in a lathe - would a Morse taper hold? Or would one just let the force rotate the attachment to the stable position?
Click to expand...
The tool I sent to you will not rotate, the MT will hold it in the tail stock. You use this tool when turning between centers, last I did that I put my face plate on used a make shift dog and a dead center at both ends, I wasn't turning a taper though. this tool will allow you to cut a taper without moving your tail stock and needing to realign it.
 
verbotenwhisky said:
The tool I sent to you will not rotate, the MT will hold it in the tail stock. You use this tool when turning between centers, last I did that I put my face plate on used a make shift dog and a dead center at both ends, I wasn't turning a taper though. this tool will allow you to cut a taper without moving your tail stock and needing to realign it.
Click to expand...
Second the not touching the tail stock once you have it aligned: unless you have added set screws to help with the alignment procedure it is a pain. eBay has a number of variations on what you found on Amazon without the graduations and/or hand wheel, but $100 is probably worth it to save the effort of re-alignment.
 
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