Annular cutter on the lathe

[rabler]

Just a little side project that worked out nicely. I made up a holder for the typical 3/4" weldon shank annular cutters to work on my lathe. A male morse taper 3, with a 3/4" hole and set screw on the end.

My lathe tailstock and my toolpost drill chuck mount are MT3, so I can use this to throw annular cutters in the lathe. The cutter illustrated above is 1.125 diameter by 2" maximum depth. Ideally I would have milled a tang on the end, but that got truncated when I realized my compound only had 3" of travel and the MT3 is spec'd 3.19" long with tang. I just left the tang off, although it would have been possible to work around that and make the taper longer by stepping over with the carriage and making the tang taper a few thou less. I may yet make another one fixing that.



Works pretty well. I was originally going to drill then bore this, but snapped a drill bit off on the initial 1/4" pilot hole, so this was my way of getting around the piece of embedded drill bit. I still need to bore it out to finish dimensions.

Sure, would have been faster to just throw away the part and start again, but what's wrong with spending a few bucks and a few days (shipping on the cutter) to save a $15 slug of steel?

 

[Video_man]

Nicely done. I might offer that I found annular cutters to apply quite a lot of torque on my tailstock and I got an MT3 toolblock for the cross-slide to mount the adapter in. I turned a 3/4" inch piece of steel to a point to aid in centering the cutter, replacing the point tool with the cutter when centered. I was concerned that the tailstock basically extends from the casting held in place only by an internal pin and groove and if they were damaged, hard to replace. Just a thought....

 

[woodchucker]

I made screw in tangs for my MT's that I use in the mill and tailstock.. That way I get the best of both with one tool.

 

[rabler]

I made screw in tangs for my MT's that I use in the mill and tailstock.. That way I get the best of both with one tool.

Certainly a good idea if you need it. I guess your mill likes morse tooling without a tang?
For annular cutters I would use a 3/4” R8 weldon shank tool/endmill holder in my mill, for my lathe both the toolpost mt3 mount and the tailstock take tangs.

 

[sdelivery]

I would suggest making a new one with a tang, because you don't want it to spin.
I do not like to drill from my cross slide and have never seen it in 30 years.
The forces from drilling using the cross slide are different from typical lathe cross slide work.
Can it be done? Absolutely machinist monitor and adjust cutting forces for tool life, cutting accuracy and finish.
It would be something in my tool box I can use when I decide I have no other choice.
Next time you run your lathe throw a couple dial indicators on your slide with the stylus on the ways make different operations and watch the affects.
There is very good reason the tailstock is on center with the spindle and has a quill.
It is typically locked in place on the ways before operations
Look at most lathe ways, the rear is generally flat and not designed to control twisting motion. It is just horizontal control.
That generally falls on the front Vee ways and that's were your increased surface area and shape control twisting.
Now if you are thinking but I am using the x slide and it is a dovetail slide, it can control those forces! Yes, A Dovetail slide is a rigid slide and it can control those twisting forces....by transferring the forces to the z slide.
Before you start arguing, just put some indicators on your machine and try different operations.

 

[Firstram]

If you are going to use annular cutters more than once in a while, buy or make a proper arbor. They have a spring loaded centering pin that ejects the slug and are coolant thru. The coolant makes a big difference in the cutters lifespan. It doesn't need much flow but, it's delivered through the center and keeps all the teeth lubricated.

 

[FOMOGO]

You could just slot the end of the taper, and silver solder a tang in. Mike

 

[rwdenney]

Could you put the 3/4” Weldon shank in a boring-bar holder? Or a tool holder with a V bottom?

Rick “likes the idea of mounting in the carriage” Denney

 

[rabler]

Could you put the 3/4” Weldon shank in a boring-bar holder? Or a tool holder with a V bottom?

Rick “likes the idea of mounting in the carriage” Denney

Both would probably work. As with many machining pursuits there are multiple approaches. Some options may have better total grip/torque before spinning, but I'm not sure.

 

[rabler]

If you are going to use annular cutters more than once in a while, buy or make a proper arbor. They have a spring loaded centering pin that ejects the slug and are coolant thru. The coolant makes a big difference in the cutters lifespan. It doesn't need much flow but, it's delivered through the center and keeps all the teeth lubricated.

Yeah, through coolant would just be another hole tapped with an appropriate small pipe thread. I don't have a coolant system on the lathe so would have to work something out, maybe siphon and air line. A spray bottle with water soluble coolant works OK for limited use.