# Rear mount cut off tool



## jwmay (Nov 21, 2021)

Working on this now. My last project left me with a couple good size chunks of cast iron. I milled a ledge, so that it'll always mount perpendicular to the ways. Still have some cutting, drilling, milling and tapping before it's done.


----------



## rwm (Nov 21, 2021)

Good project. How are you going to hold that down? If you use the T-slots that will be a heck of a lot of drilling?


----------



## C-Bag (Nov 21, 2021)

This should be the top of my list. Every time I cutoff I’m reminded. Then other stuff pops up.

Good job.


----------



## rwm (Nov 21, 2021)

Maybe a dual purpose holder to use for parting and for threading away form the chuck?


----------



## jwmay (Nov 21, 2021)

rwm said:


> How are you going to hold that down? If you use the T-slots that will be a heck of a lot of drilling?


The plan is to use the t slots. I quit for the day, to sort it out. I'll either mill a pocket for a nut,  or drill all the way through it. But I have another idea that I'm working out. I just need some time to percolate. 


rwm said:


> Maybe a dual purpose holder to use for parting and for threading away form the chuck?


Ooh now there's an idea! I hadn't thought of that. Thanks!
My original intent was that it would carry two different thickness cut off tools on opposite sides. Flipping the tool holder end for end would have presented a different tool to the work. But then I saw that my 1/8" cut off tool insert holder is cracked. It's a funny shaped thing. So I abandoned that idea until I get a new one. No reason to go to the trouble of milling a special pocket into this for an insert holder that is almost broken.


----------



## rwm (Nov 21, 2021)

The problem with my idea is that the parting tool will run inverted but the threading tool will run upright with the lathe in reverse. So having both tools at the correct height with one slot is problematic. Perhaps a second slot on the other side of the vertical? Then you turn it around depending on the application?


----------



## epanzella (Nov 21, 2021)

I built a tool block for an old Logan lathe many years ago. One side  was cut for a conventional tool holder and the other was for a cut off tool. I made a tapered spacer plate for under the the block to give me fine height adjustment by sliding it back and forth. (the center hole was slotted). Maybe you can take way something from that.


----------



## jwmay (Nov 21, 2021)

rwm said:


> Perhaps a second slot on the other side of the vertical? Then you turn it around depending on the application?


Almost exactly what I was thinking. Thanks!


epanzella said:


> One side was cut for a conventional tool holder and the other was for a cut off tool.


Yep! Thanks!

That moves the needle a little further to the right! The tapered piece has me stymied in the moment, but I think I get the gist.

It'll probably be the weekend before I get back to it. But the last two replies are along the right lines of what I want to do.


----------



## Lo-Fi (Nov 22, 2021)

Nice one and welcome to the club! Rear mount parting is the best thing I've ever done for my lathe. +1 on a second slot on the other side of the post for a threading tool.


----------



## epanzella (Nov 24, 2021)

jwmay said:


> The tapered piece has me stymied in the moment, but I think I get the gist.





jwmay said:


> epanzella said ; The tapered piece is just a fine height adjustment. Picture a 4" x 6' inch plate with a 4 inch slot down the middle. The piece is machined on a taper so that one end is .600 thick and the other end is .400 thick. It goes under the tool block and is locked down by same the center bolt that holds the tool block. By sliding the tapered plate back and forth you can get about .100" of vertical height adjustment.


----------



## jwmay (Nov 24, 2021)

Ok that's what I was thinking, but giving dimensions is great. Was the central hold down bolt hole slotted or purposely oversized? Seems like it would have to be to keep from bending the stud when it was tightened. I guess .100 may not be enough to affect it? I'm curious cause it seems  like a great way to get some adjustment without any fuss.


----------



## jwmay (Nov 24, 2021)

Oops you answered that. Sorry.


----------



## epanzella (Nov 25, 2021)

jwmay said:


> Ok that's what I was thinking, but giving dimensions is great. Was the central hold down bolt hole slotted or purposely oversized? Seems like it would have to be to keep from bending the stud when it was tightened. I guess .100 may not be enough to affect it? I'm curious cause it seems  like a great way to get some adjustment without any fuss.


The central bolt was longer than it needed to be so I just used a pair of oversized nuts as spacers. I turned them slightly convex so they could pivot without binding. This was certainly no QCTP but I used it for years with no problem. It beat the hell out of the lantern tool holder that it replaced. I also had planned for it to spin around 180 degrees so I could use negative rake carbide inserts but that didn't work out as my old belt drive machine didn't have the juice to run at the speeds and feeds required by carbide inserts.


----------



## redgrouse (Nov 25, 2021)

Not sure about advertising but I am not a commercial outfit ! However I do have a few of these available primarily for Myford lathes, all UK made not imported fully hardened and ground,  I guess they could be adapted to other small machines as well.  If they are of interest please message me with your email for pics etc
John


----------



## jwmay (Nov 25, 2021)

Well that would be great John, but I'm about half done with mine. If it doesn't work out like I hope, I'll let you know. Your version is at least a couple steps above what I've got here. But the cast iron has been cut. There's no going back now! Lol


----------



## Lo-Fi (Nov 25, 2021)

Pics and let us know how you get on please, @jwmay !


----------



## jwmay (Nov 26, 2021)

Well after some shuffling around, and scratching my head, I decided that I don't have the skill to make anything very fancy at all. So, I cut off the extra, drilled and tapped two holes for set screws, drilled one hole for a hold down, and mounted it. Drum roll please...
Yep! This is astoundingly, amazingly, and incredibly the most dramatic improvement I've experienced. In my opinion, if you haven't done this yet, there's no time like this weekend to give yourself an early Christmas present. I'm going to use it as is for now. Eventually I'll add a slot to the other side for another cutter. But time just gets so squeezed, I needed it done already. So there we go! Done already!


----------



## brino (Nov 26, 2021)

@jwmay ,

The tool post looks great and the results do too!
(....but even better is your description.)

This is on my long list of projects, unfortunately first I'd have to replace the funky, curvy cross-slide on my Southbend 9".......

-brino


----------



## Lo-Fi (Nov 26, 2021)

Nice job! It's quite amazing how well it works, isn't it. 

I'm using HSS with mine:


----------



## jwmay (Nov 26, 2021)

Well everybody says the little Southbend lathes are so much more solid than an Atlas that maybe it's  not as important. But I have been using a hacksaw. It took me a couple years before I got my cross slide done, if I remember right. So maybe you can't do it THIS weekend. But if you're experiencing any trouble with cutting off, this is the solution.
Andy Lofquist at MLA Toolbox will hook you up with a cross slide casting for your SB that has tee slots in it. I'm sure you've heard. But if not, check it out. http://www.mlatoolbox.com/S-4382.html


----------



## jwmay (Nov 26, 2021)

Lo-Fi said:


> It's quite amazing how well it works, isn't it.


Definitely! I'm pretty sure your insistence on how much better it was, is what got me started on it. Well...that and my hacksaw.


----------

