# Can I hold a 3/8" HSS bit directly in the lantern toolpost?



## cdhknives (Aug 14, 2013)

Any reason this won't work to help with my flex/rigidity issues to true up a 7/8" rod in prep for threading?


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## Chuck K (Aug 14, 2013)

If the height is right  and it's rigid I don't see why you couldn't.

Chuck


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## cdhknives (Aug 14, 2013)

It's gotta be stiffer than what I'm seeing this evening!:angry:


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## Terrywerm (Aug 14, 2013)

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?


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## wa5cab (Aug 15, 2013)

You should be able to pull the cutter back a bit, which will stiffen it some more.  Just make sure that the compound can't touch the workpiece.

Robert D.


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## mikey (Aug 15, 2013)

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?


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## GK1918 (Aug 15, 2013)

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


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## pdentrem (Aug 15, 2013)

Based upon the photo, you could shorten the overhang by almost half if not more. I have turned rifle barrels in the Atlas, using the lantern setup with no chatter etc.
Pierre


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## DAN_IN_MN (Aug 15, 2013)

> Can I hold a 3/8" HSS bit directly in the lantern toolpost?



Let's find out!


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## cdhknives (Aug 15, 2013)

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.


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## pdentrem (Aug 15, 2013)

Have you tighten the gib on the BACK of the carriage? Lots of people forget that there is one back there to hold the carriage tight against the frt surface of the ways.
Pierre


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## cdhknives (Aug 15, 2013)

pdentrem said:


> Have you tighten the gib on the BACK of the carriage? Lots of people forget that there is one back there to hold the carriage tight against the frt surface of the ways.
> Pierre



Yes.  Also, the compound is almost too tight...very stiff to turn the crank.  I thought I had done the cross slide too but I could see it moving...so either I didn't or something worked loose.


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## mikey (Aug 15, 2013)

Okay, assuming you tightened up all the gibs and are keeping bit overhang at the minimum then it comes down to your lathe tool and cutting conditions. I don't use W-1 (prefer O-1) but I have a few suggestions you might try.
1) I suggest grinding a finishing tool. I know you need to face with it but it will work for that, too. Keep the side relief angle at about 10 degrees and the end relief angle about 10 degrees. I would boost side rake to about 14-15 degrees to improve chip clearance and keep cutting temps lower. I would also increase back rake to about 10 degrees to put more of the cutting force at the tip - this will help when you are trying to size that rod. I would keep the nose radius between 1/64-1/32" max. Hone the tool before use.
2) When facing the end align the side cutting edge so that the cutting is done just behind the nose radius and feed in with the cross-slide feed. Turning speed for 7/8" W-1 works out to about 785 RPM but that may be a bit fast. You will need to figure out what works for your lathe but on mine I would start at 350 and go up as tolerated.
3) For finish cuts I tend to go much faster than recommended - tool steels finish super-nice at speeds above 1800+. This is with very light cuts in the 0.002" range. 

Hope this helps.


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## pdentrem (Aug 15, 2013)

Mikey hit all the points that I could think of at this time. Sharp tool, smaller tip radius to lower the cutting pressure, smaller and finer feeds will help you a ton. 

When you go to cut that 7/8" thread, you will have to take light cuts with a very sharp tool. Use lots of lube as well. Everybody says that! It can be done even on an Atlas. I cut 12 tpi square threads for my second Savage 99 barrel, with my hand ground tool and that was sketchy, as at the time it was early in my experience with this lathe.

Make sure that the top compound gib is the full lenght and properly adjusted front to back. Mine came with a short gib and this gave me fits until I looked at it. 
Same for the crossfeed slide. Sometimes the gib screws are not evenly adjusted or the tips are not in their locating holes on the gib strips.

The brass feedscrew nut is not a problem as you have to take up the backlash anyways.

How is the lathe bolted down? On a solid and strong bench that can not twist as the bed tries to move around under load?

Check the bearing plates under the carriage frt and back for excessive space. Can you lift the carriage up off the ways at the frt or back? May require reduction in the shim stack. If it is still there! I had issues here as the ways were worn in the first 6" , and if I tighten for that area as the carriage moved to the tailstock, the carriage would tighten up to near jamming. I ended up using belleville washers on the bearing plate bolts, to allow some give in the bearing plate to underside of the ways. This step will help more for chatter.

Getting further in, remove the top slide and check that the dovetails are not worn excessively towards the front. Use a straight edge to check and measure across from end to end to see the difference in width. You can fix this but takes a bit of time and finese(sp). Do the same for the crossfeed dovetail as well if you still are having issues but usually it is the top slide that has the most wear.
That is all I have for now. Bed is calling.
Pierre


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## george wilson (Aug 17, 2013)

Your tool is ground all wrong. Large radii like shown are begging for chatter. There is no top rake or chip breaker groove. Get a lathe book and study how cutters are ground for the best results. You need to be really careful to grind tools for a light lathe like an Atlas. I had one! I know!!

It is necessary to remember that those chips have to have some place to EASILY go,not to just be crammed straight down on a flat surface. That makes it much harder to cut easily. The radius of the cutting portion should be just large enough to span the distance between the successive lathe cuts you make as the tool is power fed along the cylinder you are turning. A tool with a 1/64" radius is plenty large enough to span fine feed cuts(so you aren't just making a very fine thread,but instead generating a smooth surface.) A chip breaker groove very near the cutting edge will curl chips so tight,they break off in short pieces shaped like 6's or 9's. The chip breaker groove needs to be pretty narrow,as if it was ground with a 1/16" cut off wheel,or the corner of a sharp edged grinding wheel.

I say the chip breaker groove should be very near the cutting edge because a "false edge" of impacted steel will soon build up,forming the actual cutting edge.


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## cdhknives (Aug 17, 2013)

Yes I know about the bit...as stated above I was in the middle of grinding it and threw it on the machine for the picture...might as well see if it was a bad idea before spending much more time working on it.

It worked (with a properly ground bit), but really left me with a lot of unusable stock because I couldn't get close to the dog.  I was hoping to get 2 dies from this piece of stock but it didn't happen!

I cut my first threads too.  They are tight, but the surface finish is a bit rough.


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## cdhknives (Aug 17, 2013)




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## george wilson (Aug 17, 2013)

Still a peculiar looking bit. I encourage you to buy "how to run a lathe" or the Atlas handbook. They have pictures of how bits should look,though they are outdated and do not include chip breakers. I am too tied up right now to post pictures. Maybe someone else could.


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## pdentrem (Aug 17, 2013)

In the parts, bits and pieces that came with the lathe, did you see any tool holders? Such as shown in the first picture.
What you need is an offset holder that twist to the right. There are also an adjustable end type that is the same as your tool holder but sized smaller. Usually for 1/4" tools. That is shown in the second picture. That way you can get closer to the chuck end of your work. You can also grind a HSS tool blank to accomplish the same thing. Basicly you would grind a shape similar to a boring bar but with the cutting tip facing in instead of out, if that makes any sense. The older Machinery's Handbooks have drawings show these special shape tools. 
Pierre


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## cdhknives (Aug 18, 2013)

I have a bunch of tool holders and have been using them for aluminum and wood, but when I see the top of the lantern flexing 1/8"+ at the start of a .005" cut into W1 steel drill rod I started looking for ways to stiffen the whole thing up.  Hence the start of this thread.

The bit I ground cuts nice long (got one over 6') springs about 1/8" in diameter on light cuts (.002").  It has 15 degrees of relief under the nose and about 15 degrees rake from the left edge.  Since I'm grinding it by hand on my belt grinder it gets dang hot (yes I dunk it in water periodically) so I only ground a little behind the edge...no reason I saw to grind the whole top face back to get edge rake.  The front vee is about 90 degrees with a slight roundover taking off the point.  Finally it gets honed to near shaving sharp on a 600 grit diamond stone.


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## Codered741 (Aug 18, 2013)

Just to clarify, in what direction are you seeing the movement? E.g. parallel with the carriage, or with the cross-slide/compound?  Are you turning or facing when this happens?  Just off hand, it seems that the problem was with your cutting tool, not your machine.  What does the original tool look like?

If I understand what you are saying, it seems to me that the bit does not have enough clearance, or is set too high above the center line of the part.  If the entire tool holder is flexing, make sure that it is securely locked to the t-slot, and there is no swarf that it could be rocking on.  I have also seen rocker posts that are worn out, and splitting in the center of the t-nut.  

Also, when facing saw cut pieces, be sure to lock the carriage to the ways.  Either use the carriage lock, if equipped, or disengage the lead-screw feed, and engage the half-nuts.  (I use this all the time on my mini lathe.)  

-Cody


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## pdentrem (Aug 18, 2013)

Just a few thoughts that have come to mind.

1. Do you have the top slide advanced pretty far or is it retracted towards you as much as possible? I am thinking that the top slide is flexing at the t-slot area if it is not supported by the upper swivel which has the lower dovetail. 

2. Was the top slide ever cracked or broken through the t-slot? The reason is that mine had been repaired in the past and it was not flat on the underside. The forward section of the t-slot was suspended in mid-air so my tool holder would bob back and forth as the load varied. That can be corrected by lapping on a flat glass plate or cleaned up on a surface grinder, but the dovetail may need addressing if too much metal is removed.

3. How are the swivel pins that hold the lower swivel base to the cross slide? Good fit to the angled circular surface or more squarish and more like a small line contact leaving little surface to lock it down securely. Also check that the swivel base is not cracked around the swivel. This happens even on bigger machines. Likely have to remove it and look at the underside for cracking.

That is it for the moment.
Pierre


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## mikey (Aug 18, 2013)

First, congrats on getting the part made. You may have had to fight for it but you got it and you should feel good about it. 

Second, if the threads are rough then there are many conditions that can do that - cutting speeds, whether the tip of the tool is on center, proper tool geometry, cutting fluid type, technique (how much you take off per pass, feeding with compound or straight in, etc), tightness of your gibs and tool holder, and probably other things I've missed. If the fit is tight but your thread form is good then perhaps a spring pass or two might have helped. If at all possible bring the mating piece to the lathe and check fit, then cut until you get the fit you need. 

Third, you ground a tool that did the job - great! It might not look or work as well as you might have liked but it got the job done. Nobody starts off grinding tools like a pro - nobody - stay with it and don't be discouraged. In time you'll be able to grind tools to suit whatever your needs are. 

Fourth, consider a quick change tool post. 

Thanks for sharing your project. It took me back to my newbie days and for what its worth, I didn't do nearly as well as you did. Hang in there ... it will come.


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## cdhknives (Aug 18, 2013)

Done with die #1.  Now for a crimp die.




The rocker is pretty badly worn/mashed up.  A QCTP is probably going to have to wait unless I find a ridiculous deal...I've already spent too much getting this 'free' lathe up and running.

Yes the carriage is locked and the compound is retracted enough to have the front slide dovetail bearing, not hanging into air.

There is no sign of damage or repairs anywhere except for some minor dings in the bed here and there.

No guarantees on mounting pins.  They looks like a piece of rod ground with a 45 degree side about half their thickness and rounded off.

I guess I need to shoot a short video showing the setup and what it's doing.


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## pdentrem (Aug 18, 2013)

Atleast now we know that area is not the issue with the movement. A QCTP will not fix the problem if it is more than just the tool post that is moving. I did put a QCTP on my Atlas, made setups much quicker. Now it lives on my other lathe, as I sold my Atlas last year. Atlas are good within their operating envelope, just have to find what your problem is and fix it. Keep looking and report back. We are here to help.
Pierre


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## Matkins (Nov 24, 2013)

I am interested in the .45 cartridge you are making. As I started reading the thread I was wondering how you were going to get it to headspace but your picture shows nice even shoulder for that purpose. Would love more info as to how you machined the ID of the forming die! BTW, do you have your knives on the market? I saw some that looked just like the one in your picture at a hardware store in Cuero.


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## cdhknives (Nov 25, 2013)

Matkins said:


> I am interested in the .45 cartridge you are making. As I started reading the thread I was wondering how you were going to get it to headspace but your picture shows nice even shoulder for that purpose. Would love more info as to how you machined the ID of the forming die! BTW, do you have your knives on the market? I saw some that looked just like the one in your picture at a hardware store in Cuero.



This is my guide for the shotshell project.  The link is to my Dropbox account...let me know if you can open it.  I tried to set it to publicly available.  It basically follows a 1971 article by C. E. Harris in American Rifleman.  Die dimensions are included.  I ended up making a 3 die set as necking in one step was crushing cases, so I have 2 dies to reduce the mouth in stages.  Tuning the loads in my pistol has been problematic.  About 20% still jam...usually lengthwise in the ejection port.

https://www.dropbox.com/s/hzccrzepqmtcm5c/45_shot_cartridge dies.pdf

I only sell knives by word of mouth or on forums like this on the rare occasion I have one built and not already spoken for.  Lately I'm running a 2 year backlog, mostly because I've found it very hard to break away from other projects to do knife work.  The '3 finger knife' in my avatar is not a common style, but you can find similar knives here and there.  So far the one pictured is the only little one I've completed in that style.


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## lrsglory (Nov 25, 2013)

The three ( 3 )  rules of good machining. Rigidity, Rigidity, and then there is Rigidity. !!!!!!!!!!


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## Matkins (Nov 26, 2013)

cdhknives said:


> This is my guide for the shotshell project.  The link is to my Dropbox account...let me know if you can open it.  I tried to set it to publicly available.  It basically follows a 1971 article by C. E. Harris in American Rifleman.  Die dimensions are included.  I ended up making a 3 die set as necking in one step was crushing cases, so I have 2 dies to reduce the mouth in stages.  Tuning the loads in my pistol has been problematic.  About 20% still jam...usually lengthwise in the ejection port.QUOTE]
> 
> Thanks for the information, I was able to access your Dropbox just fine. I think this will be a worthy project for me to attempt. I know this is getting away from the the thread, but on the topic of jamming, have you experimented with recoil springs of different weights specifically for the shot loads? You would want to change back to the heavy spring for hotter loads so another choice might be a combination of an extended ejector and a lowered ejection port if you are using a stock gun. My thoughts are to make the gun reliably eject anything that you run through that has enough energy to fully cycle the slide. I may be preaching to the choir here and if that is the case I apologize, I get carried away when the subject turns to .45's.


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## cdhknives (Nov 26, 2013)

I still have the factory spring and guide rod installed.  I have shied away from a light recoil spring because where I am (about 1 hours from the TX-Mexico border) is a known corridor for all kinds of bad traffic, and this is my field carry pistol.  I want to be able to reliably use full power ammo with only a mag change...or better yet load the top 1-2 with snakeshot and the balance with hollow points...for 4 or 2 legged coyotes.


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## Matkins (Nov 26, 2013)

I understand your concern, I live about an hour north of Corpus but I spend time in Zapata fairly regularly.


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