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Can I hold a 3/8" HSS bit directly in the lantern toolpost?
- Thread starter cdhknives
- Start date
- Joined
- Jan 16, 2020
- Messages
- 8
Yup, just like Chuck said, if the height is right, it should work. The only problem I see is that there is quite a bit of that 3/8" tool that is unsupported. If it were mounted in a toolholder, the tool itself would be supported much closer to the cutting edge than it is now, lending greater rigidity to the tool. I suspect that the setup shown will have quite a bit of trouble with chatter if you try to take any substantial cuts. If you keep your cuts down to .010" or less you might be okay, but I doubt you could do anything much deeper than that with that setup.
Keep in mind that this is just my opinion based on your photo. I guess the best thing to do would be to give it a try and see what happens. You will let us know, won't you?
Keep in mind that this is just my opinion based on your photo. I guess the best thing to do would be to give it a try and see what happens. You will let us know, won't you?
- Joined
- Dec 20, 2012
- Messages
- 9,422
In addition to the replies above, I would add that a tool with a flat top rake and large nose radius will increase chatter a lot unless you go at very slow cutting speeds and take very light cuts. What kind of metal are you cutting? Do you have a lot to take off?
- Joined
- Nov 21, 2010
- Messages
- 1,602
Just curious, what is the issue in the first place. The lathe appears to be heavy duty enough. Every one else answered the question (except) I have one lathe that I constantly have to check the crosslide gibs that someone fooled with maybe 70yrs ago, And it still has a lantern, "big bucks for a quick change for this one". So its safe to say all machines have their own personality I know exactly what you are doing and for threading, I wouldnt worry to much about phonograph groves, they'll go away, just get it round. samuel
- Joined
- Apr 12, 2013
- Messages
- 562
I'm trying to make a custom sizing die for reloading 45ACP snakeshot cartridges. The goal is to take cut off (1.25") 308Win rifle brass and neck it down enough to simulate a loaded 45ACP cartridge. Add a cut off 410 shotgun wad and overshot card and you have max capacity 45ACP snakeshot with enough oomph to cycle the slide of a 1911.
This is a 7/8" W1 drill rod from my local Rex Tools store. I have faced and center drilled both ends for centers, and now I need to lightly true up the surface in prep for threading it 7/8-14. I will then bore and polish it internally. I was turning it at 164 RPM...slowest speed in direct drive.
Yes I can shorten the bit overhang. I threw it in quick just to get a picture. I was also in the middle of grinding a new bit...tightening up the radius on the tip is no problem.
The problem I'm having is that when I was facing the end to square it up (sawzall cut off a 6" piece, 7/8" is too big to slip through the headstock but I was able to get it to about 1.5" of my 6" piece hanging out the front of the chuck) the tool was walking and flexing all over the place. I may have some looseness in the cross slide gibs I can adjust out, but it was pushing the bit tip all over instead of really biting in and cutting chips. After several re-adjustments of the toolpost angle and switching to a fine radius tip bit I was able to get it squared up enough to center drill but it took over an hour just on one end. I had the carriage locked down and was using the compound (already at 29.5 ready for threading) to advance the bit, but it would pull whole cross slide forward and back (loose cross slide nut...known issue) and flex the bit+holder+toolpost back and forth. I was able to physically lean into the cross slide (hard, to preload the whole assembly) to counter the loose nut but the toolpost flex was not completely solvable. I just took 2-3 passes at each depth and it would mostly knock off the high points eventually.
I was advancing the compound a tenth of a rotation each time (.01" at 29.5 degrees to the cutting axis) and using a medium cutting oil. The ends look like they were chewed out, not cut, but they were flat enough for the center drill and that is really all I needed.
I figured that much flex just in facing would lead to chaos when turning and threading, so I was looking for more rigid ways to make this work.
This is a 7/8" W1 drill rod from my local Rex Tools store. I have faced and center drilled both ends for centers, and now I need to lightly true up the surface in prep for threading it 7/8-14. I will then bore and polish it internally. I was turning it at 164 RPM...slowest speed in direct drive.
Yes I can shorten the bit overhang. I threw it in quick just to get a picture. I was also in the middle of grinding a new bit...tightening up the radius on the tip is no problem.
The problem I'm having is that when I was facing the end to square it up (sawzall cut off a 6" piece, 7/8" is too big to slip through the headstock but I was able to get it to about 1.5" of my 6" piece hanging out the front of the chuck) the tool was walking and flexing all over the place. I may have some looseness in the cross slide gibs I can adjust out, but it was pushing the bit tip all over instead of really biting in and cutting chips. After several re-adjustments of the toolpost angle and switching to a fine radius tip bit I was able to get it squared up enough to center drill but it took over an hour just on one end. I had the carriage locked down and was using the compound (already at 29.5 ready for threading) to advance the bit, but it would pull whole cross slide forward and back (loose cross slide nut...known issue) and flex the bit+holder+toolpost back and forth. I was able to physically lean into the cross slide (hard, to preload the whole assembly) to counter the loose nut but the toolpost flex was not completely solvable. I just took 2-3 passes at each depth and it would mostly knock off the high points eventually.
I was advancing the compound a tenth of a rotation each time (.01" at 29.5 degrees to the cutting axis) and using a medium cutting oil. The ends look like they were chewed out, not cut, but they were flat enough for the center drill and that is really all I needed.
I figured that much flex just in facing would lead to chaos when turning and threading, so I was looking for more rigid ways to make this work.