Jacket Draw and Trim Die, -S type
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Catalog No.: ET-1-S
Shipping Weight: 0.25 pounds
The ET-1-S Trim Die pinch trims jackets to a specific length, controlled by the dimensions of the punch (different length trims require a different punch). The advantage is that the jacket is cut off in one stroke as the jacket is reduced by at least 2x the wall thickness.
The disadvantages are:
The advantages are:
- Each trim length requires its own punch.
- A jacket must be reduced by at least 2x wall thickness.
- Jackets must be reduced in order to be trimmed.
- Larger jackets can be reduced and trimmed in one stroke.
- The trim results in complete separation without further operations.
The die operates by using a step shoulder on a punch with two diameters. The larger diameter just fits into the die by itself, leaving no room for the jacket.
The smaller diameter, which is the length of punch that will result in final jacket trim length, fits the ID of the jacket as it is reduced in the die.
The entire punch, both diameters, must fit inside the jacket prior to reduction. The jacket with smaller portion of the punch passes through the reducing die, but as soon as the larger diameter of the punch enters the die, it pinches the jacket off against the die opening. The cut portion of the jacket is mashed and may split or compress on the punch, where eventually it either comes off by itself as scrap or is removed by the operator.
This puts a minimum required difference between the desired final jacket diameter and the initial jacket size, based on that jacket's wall thickness. For example, a .308 jacket with .020 inch walls (at the trim point) must be reduced to at least .268 diameter. It cannot be reduced to .284 or .277 because the wall thickness (times 2) would not allow the punch to clear the jacket ID and trim the jacket.
Actually, a .308 jacket is probably .3065 diameter. If the wall thickness is .018 inches at the trim position, then the minimum diameter of draw can be .3065 - (.018 x 2) = .2705 diameter jacket. This would be just a little small for a .270 (.277) bullet. Drawing to .263 would be entirely practical, for making 6.5mm bullets.
The ET-2-S die is preferable for most applications because it doesn't require reduction during the trim, and is adjustable over a wide range of lengths with one die. However, the ET-2 die does not necessarily trim completely without additional user action to remove the trim portion. It leaves a very thin connecting film after cutting, to protect the cutting edge, so that the trim is removed by tumbling, or mechanically removing the cut portion with a pair of needle nose pliers.