Lee Collet Die

[bigedp51]

After even more reading about the Lee Collet die online to "re-educate" myself on how to adjust and "fine tune" a Lee collet die, here are the results.

Well under .001 case neck runout.

http://i122.photobucket.com/albums/o254/bigedp51/IMGP7152.jpg

Less than .001 bullet runout on my case forming loads using the Lee Collet die.

http://i122.photobucket.com/albums/o254/bigedp51/IMGP7155.jpg

This is fantastic considering the long fat chamber on the military .303 Enfield rifle and the fact that commercial American SAAMI cases have smallish base diameters and thin rims that greatly effect headspace. If you are not careful with our American .303 cases it is very easy to end up with a banana shaped warped case in the Enfield chamber.

One of my online reading finds last night was to "NOT" tighten the die lock ring down until it bottoms out, only use finger tight pressure on the lock ring nut to tighten it so the die can "float" and self center itself on the rubber o-ring and thus add to more accurate reloads.

My first postings in this thread were "bad calls" due to vision problems. ::)

http://i122.photobucket.com/albums/o254/bigedp51/blind.jpg

[gotcha]

bigedp51, Thanks for making my $12 fee soooo worth while. I continue to be amazed by the quality of your input. And, like the other posters, sincerely enjoy your feed-back. It ain't easy to say "I was wrong" and then have the integrity to turn around and prove it!! I'm not sure I'd have had the fortitude (much less the skills) to do that. :-\ It's been a pleasure butting heads with you. ;D Itty bitty groups to ya' Dale

[bigedp51]

Below is a very good article from Benchrest Central on how to adjust your Lee collet die on a RCBS RockChucker type press that goes over center at the end of the ram stroke. The basic problem is "some" of us apply "too" much pressure on the collet die and run into problems. What is important here is uniformity and adjusting the collet die as per below you are using the "mechanical stop" of the press to achieve crimping uniformity on each neck sized case in your Lee Collet Die.




Using The Lee Collet Die.
By John Valentine.
Benchrest Central

I started using Lee collet dies when they first came on the market and have found that they are very good for the purposes for which they were designed. I have found that there is a lack of understanding of how to use the die properly and as a result people fail to see the advantages that the die can deliver over standard neck sizing dies. This is not the fault of the product , it is just a lack of understanding of how the die works and what it will feel like when you operate the press correctly.

Standard dies use a neck expanding ball on the decapping rod and size by extruding the neck through a hole and then drag the expander ball back through the inside neck. The collet die achieves neck sizing by using a split collet to squeeze the outside of the case neck onto a central mandrel which has the decapping pin in it’s base. One advantage is that there is no stretching or drawing action on the brass. The inside neck diameter is controlled by the diameter of the mandrel and to some extent by the amount of adjustment of the die and the pressure applied to the press.

This results in less misalignment than can occur in standard dies because of any uneven neck wall thickness in the cases.Cases will last longer in the neck area and require less trimming. If cases have very uneven neck wall thickness then this can cause problems for the collet die they definitely work smoother and more accurately with neck turned cases but it is not essential.

When you first receive the die unscrew the top cap and pull it apart check that everything is there also that the splits in the collet have nothing stuck in them then inspect the tapered surface on the top end of the collet and the internal taper of the insert to make sure there are no metal burs that might cause it to jamb. Next get some good quality high pressure grease and put a smear onto the tapered surface of the collet. Put it back together and screw it into the press just a few threads for now. The best type of press for this die is a press of moderate compound leverage that travels over centre.

Over centre means that when the ram reaches its full travel up it will stop and come back down a tiny amount even though the movement on the handle is continued through to the stop. eg. is an RCBS Rockchucker. This arrangement gives the best feel for a collet die sizing operation. Place the shell holder in the ram and bring the ram up to full height then screw the die down until the collet skirt just touches on the shell holder, then lower the ram. Take a case to be sized that has a clean neck inside and out and the mouth chamfered and place it in the shell holder. Raise the ram gently feeling for resistance if none, lower the ram. Screw the die down a bit at a time. If you get lock up (ram stops before going over centre) before the correct position is found then back it off and make sure the collet is loose and not jammed up in the die before continuing then raise the ram feeling for any resistance, keep repeating this until you feel the press handle resist against the case neck just at the top of the stroke as the press goes over centre and the handle kinder locks in place.

This takes much less force than a standard die and most people don’t believe any sizing has taken place. Take the case out and try a projectile of the correct caliber to see how much sizing has taken place.
If it’s still too loose adjust the die down one eighth of a turn lock it finger tight only and try again .
Once the die is near the correct sizing position it takes very little movement of the die to achieve changes in neck seating tension. This is where most people come undone , they move the die up and down too much and it either locks up or doesn’t size at all.

It will still size a case locking it up but you have no control over how much pressure is applied and some people lean on the press handle to the point of damaging the die. A press like the RCBS Rockchucker, that goes over centre each time gives you a definite stopping point for the ram and the pressure that you apply.

There is a small sweet spot for correct collet die adjustment and you must find it , once found , how sweet it is ! Advantages : With a press that travels over centre it is possible to adjust the neck seating tension within a very limited zone. No lubricant is normally required on the case necks during sizing.

If you still cant get enough neck tension to hold the bullet properly for a particular purpose then you will have to polish down the mandrel. Be careful polishing the mandrel down and only do it a bit at a time as a few thou can be removed pretty quickly if you overdo it.

You can't get extra neck tension by just applying more force. The amount of adjustment around the sweet spot is very limited and almost not noticeable without carrying out tests. For example, to go from a .001 neck tension to a .002 or .003 neck tension you would be talking about polishing down the mandrel.

There are some other advantages but I will leave you the pleasure of discovering them. One disadvantage that I have found with the collet die is that it needs good vertical alignment of the case as it enters the die or case damage may result so go slowly.

Also some cases with a very thick internal base can cause problems with the mandrel coming in contact with the internal base before the sizing stroke is finished. If pressure is continued the mandrel can push up against the top cap and cause damage . If you are getting lock up and cant get the right sizing sweet spot, then check that the mandrel is not too long for the case you can place a washer over the case and onto the shell holder and size down on that. It will reduce the length of neck sized and give the mandrel more clearance. If it sizes Ok after adding the washer then the mandrel could be hitting the base. This is not a usually problem once you learn how to use them.

The harder the brass is the more spring back it will have so very hard brass will exhibit less sizing than soft brass because it will spring away from the mandrel more. If this is happening to excess then use new cases or anneal the necks. Freshly annealed brass can drag on the mandrel a bit in certain cases because it will spring back less and result in a tighter size diameter. I have experienced it. I always use some dry lube on the inside and outside if I get any dragging effect. Normally you don't need lube.

I make up a special batch 1/3 Fine Moly powder. 1/3 Pure graphite. 1/3 Aluminiumised lock graphite. Rub your fingers around the neck and It sticks very well to the necks by just dipping it in and out and tapping it to clear the inside neck. After a few cases it coats up the mandrel. Other dry lubricants would work also. Use the same process for normal neck sizing also.

I noticed a definite improvement in the accuracy of my 22-250Rem. as soon as I started using a Lee collet die instead of my original standard neck die.

Readers are encouraged to utilise the benefits of responsible reloading at all times. Although the author has taken care in the writing of these articles no responsibility can be taken by the author or publisher as a result of the use of this information.
John Valentine. © 21/01/2002.
*****

Last edited by J. Valentine; 03-14-2008 at 01:10 AM.

http://benchrest.com/showthread.php?49899-Lee-Collet-Die-Adjustment

[gotcha]

Possum Dude, I'm always looking for ways to tighten groups 8). So I tried the method you described above :-[ The BAD NEWS: I couldn't improve my groups >:( The GOOD NEWS: I really didn't give a s--t 8) ---------- Do ya' reckon a quarter pounder of "group tightener" might be too heavy a charge?

[Tozguy]

Unfortunately the die setting instructions given above are misleading for the reasons given earlier in this thread. With a collett die the sizing 'stop' is built in, meaning that when the neck brass reaches the stem it stops closing automatically. To continue adding an unknown amount of pressure by toggleing the press over will only stress the die unnecessarily. There is no need to find a delicate ram/die position to get correct sizing with a collett die. I invite any of you to see for yourselves. Screw your collett down as far as it will go in the press and size a case. Chances are the ram will be no where near the toggle over point and you feel the case will get sized.

[bigedp51]

Tozguy

I set my Lee Collet Die up as described above and got better and more uniform results, you are setting the closing force to minimum and are also coming to a mechanical stop that requires no guess work as to the amount force applied to the press handle.

A standard joke when I was an Inspector was if an Inspector asked the mechanic what was the torque value setting on that bolt the follow was given as an answer.

"I tightened the nut until the threads started to smoke and then gave the nut two more full turns"

The purpose of the above setup is to make all the neck sizing uniform with equal force applied to each case neck. This eliminates the differences between a 90 pound weakling and a Gorilla pulling on the reloading press arm.

The setup above removes any muscle memory errors and the grinding of gears speed shifting the press arm. This type setup removes any "human" errors connected with pulling the handle, eating your Wheaties, possible anabolic steroid abuse or the possibility of you arm falling asleep and loosing all the feeling in your arm.

The problem is always connected to the nut pulling the handle and the force applied.

http://i122.photobucket.com/albums/o254/bigedp51/capscrew.gif

NOTE: The same type arguments are started when discussing what is the proper amount of "headspace".......

Below, "excess" headspace. ::)

http://i122.photobucket.com/albums/o254/bigedp51/10_foambeer_lgl.jpg

[bigedp51]

Watch this YouTube video and the Forster Co-Ax Single Stage Press with the Lee Collet die, I would say this press is going "over center". ;)

http://www.youtube.com/watch?v=RZEas38vkKg

[possum1]

Screw your collett down as far as it will go in the press and size a case. When I do this procedure in my Lee press it buckles the shoulder. ::) Do ya' reckon a quarter pounder of "group tightener" might be too heavy a charge? Alway's help's mine. ;D

[Tozguy]

Biged, I love your graphics! I understand the principle of reducing human error although it is an assumption that the maximum pressure (blue) method is more uniform than using less but enough tension. My point is to have us realize how little pressure it takes to size a neck with a collett die and that once once the neck is tight to the mandrel, no amount of extra pressure can make the neck smaller than the mandrel. As possum showed, it will give some elsewhere (example buckled case). I don't get buckled cases but I can see now how someone with a heavier press could miss the stopping point.
Possum, just curious did you feel a transition between when the collett bottomed and when the case started to buckle?
Many of us reject a powder charge from a measure if it doesn't feel normal. Like wise some of us punch out primers by hand and insert new ones by hand to feel how tight the pocket is. I like to feel the neck being sized and find it easy to tell when to stop. But I am starting to realize that it won't work for everybody.

[possum1]

Possum, just curious did you feel a transition between when the collett bottomed and when the case started to buckle? To be honest that was almost 2 years ago when I first started hand loading, My memory is about as long as my pecker, if you know what I mean.

[Tozguy]

Possum,
The only time I buckled a case was when a 223 case was accidentally run into a 222 collett die.
Biged,
Since I don't have your ability at posting would it be too much to ask that you post the die adjustment instructions provided by Lee that we receive with the die? It might be a more reliable reference for us.

[gotcha]

tozguy, much of this discussion is because the Lee collet die instructions are pretty vague. You can google:" Lee collet die instructions" to find a number of ways to set neck tension. Some recommend either polishing down the mandrel( referred to in the Lee instructions) or buying a larger mandrel and "turning" down to a Dia. that suits your nk. tension needs. You could also buy an expander mandrel die from Sinclair, squeeze the neck down with the Lee die then run the case through the expander mandrel die. With the Lee die you don't need the extra steps or expense of the seperate expander mandrel die. If I set my.223 nk. tension to .002" the collet doesn't move enough to crush the nk. against the mandrel. In this method the ram moves to the"stop" which is actually the limit of ram travel of my Rockchucker. Also, the stopping point is controlled by the depth of the die in the press since the collet has not yet fully closed on the neck. The tapered sleeve does, however, make contact with the collet insuring the case is centered in the die and thus the neck centered to the base. By not crushing the neck against the mandrel there are no "indents" in the neck making it easier to determine and maintain concentricity with a dial indicator and also less neck damage is experienced. Less movement of the nk. diameter causes less work hardening. The "feel" of neck reduction is still there and will be on larger cases with the exception of Norma brass which I won't get into now. Its also a good idea to tune your collet die by deburring, polishing and lubing (we all know that!) Your " camming over " effect is a point well taken.

[bigedp51]

Biged,
Since I don't have your ability at posting would it be too much to ask that you post the die adjustment instructions provided by Lee that we receive with the die? It might be a more reliable reference for us.


And I thought you liked me because of my beautiful mind, now I find out you only like me because I cut and paste on the first date............................ Sigh, I feel so used and abused. ::)


http://i122.photobucket.com/albums/o254/bigedp51/Colletsetup.jpg

http://i122.photobucket.com/albums/o254/bigedp51/colletbuckled.jpg

[bigedp51]

NOTE: I used the collet die on three different brands of cases, all three brands were neck turned for a constant neck thickness for testing. The Winchester cases did not drag or touch the mandrel on the up stroke of the handle, this means the "springback" of the brass is determined by the hardness and annealing of the necks.

As a second test I necked sized the cases in a RCBS neck die and then put them in the Lee Collet die to test for "feel" on the mandrel in both directions. The Winchester cases still felt loose on the manderl after sizing in the collet die.

Bottom line, some cases have less Viagra added to the brass mixture which effects neck tension.

http://i122.photobucket.com/albums/o254/bigedp51/brasshardness.jpg

[Tozguy]

Biged, much appreciate your help, you are always there for us and we love you for it :-*

[kelbro]

I set my .223 collet die up with the ram on my Rockchucker at the top. Slowly tighten the die until sizing occurs. Doesn't take much. Very repeatable with long loading sessions. Brass doesn't go more than three loads before being annealed so they are quite consistent. Average .0015-.002 runout. Works for me!