李公司顶级转盘式夹紧套件

Summary

If you install any of the devices described here on your press, then you, and not the author, are responsible for whatever happens to you, your press, these devices, or anything else in the vicinity.

What is this thing?
The Lee Precision Ultimate Turret Press has what many of its users call a flaw in the design of its auto-index behavior. As you finish the ram stroke, the spinning of the turret from the index rod is stopped only by friction on the base of the turret. The instructions say lubricate it with grease or STP but regardless of lube, many users find the turret over-advancing way too often. "Many users" includes the author.

The bracket below installs under the turret mounting bolt closest to the ram and provides more friction. The brakes install under the other two mounting bolts, and balance the friction a bit. The default parameters leave the bushing mate protrusion turned off. A rendering of it turned on is among the images posted with this thing.

The exact condition and calibration of the 3D printer, including the condition of the filament all affect the amount of friction the brakes apply. The extrusion multiplier (among other settings) can change the dimensions of the final print by several thousandths of an inch, and, unfortunately, those thousandths matter.

You may have to customize the model, especially the BracketRadialGap parameter, to tweak the parts so that they apply an acceptable amount of friction on your printer. A smaller BracketRadialGap gives more friction.

The type of plastic used to print this is important due to the fact that (a) the bushing mate must be flexible enough for the index rod to push it out of the way as the indexing starts. PETG seems to work well enough and (b) the surface of the Brakes provides friction against the turret.

This thing does not fully cure the design issue!

1. it remains possible to actuate the ram fast enough to get enough turret angular momentum to overcome even this bracket without or without the brakes
2. Not all Lee Breech Lock bushings have the same Outer Diameter and profile. The bushing mate in this thing catches some of their bushings better than others. It helps to put all the same Breech Locks in the turret together. This is another reason the bushing mate doesn't work very well.
3. When you install the brakes, they have a small amount of rotational freedom under the turret mounting bolts. The amount of friction is highly dependent on that rotation angle because it determines the amount of force the brake applies against the turret. This problem is moderated somewhat by installing three brakes, one under each mounting bolt.

Assembly:
quantity 3 by 5/16" flat washers are required.
One of them must be filed down flat on one side to fit in the Brake #2 position.

Following Lee's instructions to change the turret, when you get to the point of installing the three mounting bolts, place the 3 parts here and their respective washers over the bolts before threading the bolts into the press.

The Bracket installs in the mounting hole closest to the ram.
Brake 1 installs at the next hole around counter clockwise from the Bracket.
Brake 2 in the remaining hole, the one that requires the flattened washer.

Do not simply tighten the 3 bolts.
Instead, thread them down barely finger tight.
Install dies in every position in the turret that you plan to use. (Really, do this!)
Slowly spin the turret (with the ram+locating pin down, of course).
If your press is like mine, there is enough play in the way the mounting bolts hold down the turret that you need to find a sweet spot so that the turret turns with more-or-less constant friction all the way around.

As you tighten the mounting bolts, keep turning the turret. These brakes are supposed to provide a bit of friction, but you should not use anything more than slight force from your hand and wrist to turn the turret.

The friction applied by these printed brakes can be fine tuned:
Loosen the bolt closest to the ram.
The brake rotates a few thousandths back and forth around the mounting bolt.
With your finger, apply some pressure towards the turret, and on the tail of the brake nearest you as you tighten the bolt back down. That brake will have more friction now.

The bracket part can be built with or without the BushingMate. The author decided the bushing mate didn't work very well because, while it does provide extra friction for stopping at the right rotational position, that extra friction is a liability when you start the next stroke because, when the bracket lets go of the tension, the turret accelerates so much it can overcome the friction when the next bushing hits the mate.

Do not bother running the very old version of OpenScad Customizer on Thingiverse with this thing. If you want to modify the model, or even simply use any of its customizable parameters, find some other way to run OpenScad. Its free, open source, and downloadable for multiple platforms.

Print Settings

• Printer brand:

  Prusa

• Printer:

  Mk2.5s

• Rafts:
  No
• Supports:
  No
• Resolution:
  0.2
• Filament brand:

  Prusa

• Filament color:

  black

• Filament material:

  PETG