Uniquetek Micrometer powder bar kit User manual

UniqueTek Inc. 540 W. Iron Ave., Suite 118 web: www.uniquetek.com

Phone: 480-507-0866 Mesa, AZ 85210 e-mail: info@uniquetek.com

Fax: 480-507-0867 - 1 - Rev. 20 04/15

Micrometer Powder Bar Kit™

For the Dillon Auto Powder Measure *

Thank you for buying the UniqueTek Micrometer

Powder Bar Kit™for your Dillon Precision Auto Powder

Measure. This kit includes everything you need to

convert your Powder Bar to a Micrometer Powder Bar.

This conversion kit is compatible with all Dillon Powder

Bars (Extra Small, Small, Large, Magnum, Belted

Magnum* plus the SL 900 Shot Bar*).

* The Belted Magnum powder bar and SL900 Shot Bar require minor

modification. See Note in Step 4 of instructions.

Before beginning installation, it is recommended that

you read these instructions completely at least twice. It

is also recommended that you review the factory

instructions and exploded parts diagram for your Dillon

Precision Auto Powder Measure. If you do not have

the instruction manual for your press, manuals are

available for download at the Dillon Precision web site.

(www.dillonprecision.com)

* Dillon Precision does not authorize the Micrometer Powder Bar Kit™

for use on any of its reloading presses and its use may void

manufacturer or dealer warrantees.

If you have any questions about installation, operation or experience any problem with your micrometer, please call

me first. I can often resolve the problem over the phone (480-216-2041 cell). – Lee

Step 1: Place an Index Mark on Powder Bar

The Auto Powder Measure is oriented differently on each Dillon press. Before

removing the powder bar, decide from which side you will want to view the

micrometer when adjusting the powder charge. As you are facing the press, you will

typically adjust the micrometer from the side shown below.

• Square Deal B – Left Side • XL 650 – Left Side • Super 1050 – Left Side

• RL 550B – Right Side • SL 900 – Right Side • AT 500 – Right Side

Mark a line on that side of the powder bar, near the adjustment screw, with a pencil,

white crayon or other marker that is easily visible but removable. This line will be

used later to orient the micrometer index mark for easy reading. On the XL 650 and

Square Deal B you will notice that the micrometer numbers will be upside-down. But

this orientation will be much easier to see during adjustment than if it was oriented

on the opposite side of the powder bar as with the other presses.

Step 2: Remove Powder Bar

Remove the Powder Bar from the Powder Measure. (Refer to Auto Powder Measure instruction manual for details.)

Step 3: Disassemble the Powder Bar

NOTE: Before disassembly, look closely at the Powder Bar and note that Powder Bar Inserts (Ex-Small, Small and

Large) and some Powder Bars (Small and Large) have a flat side and a side with a cavity. The cavities must always

be on the bottom side of the Powder Bar.

a. Remove the Powder Bar Post. Press the bolt head against a

hard surface to compress the spring washer while pulling out

the Powder Bar Post. The Belted Magnum powder bar and

SL900 Shot Bar have a 3/8” set screw instead of a powder bar

post. Remove the set screw using a 3/16” hex key.

b. Remove the Powder Bar Adjustment Screw.

c. Set aside the Powder Bar Adjustment Screw, spring washer

and flat washer. They will no longer be used.

Step 4: Prepare the Powder Bar for Installation **

The Teflon coating must be completely removed from the hole in the end of the powder bar where the adjustment

screw was removed. Use a round file or rolled up sandpaper to scrape away the Teflon coating, leaving a fresh bare

metal surface for the LocTite to achieve a good bond. Clean the hole with rubbing alcohol to remove any residue.

Note: If you happen to have a 7mm thread tap, it does a quick job of cutting through the Teflon coating and exposing clean bare metal for the

Loctite to achieve a solid bond. Only a 7mm tap is the correct size. Do not substitute any other size metric or SAE tap.

** The Belted Magnum powder bar and SL900 Shot Bar adjustment screw hole is smaller than on the other powder bars and must be

enlarged using a 17/64” drill bit before installing the micrometer. Some older Small and Large powder bars may also require enlarging.

Applying index mark (XL-650 shown)

UniqueTek, Inc. 540 W. Iron Ave., Suite 118 web: www.uniquetek.com

Phone: 480-507-0866 Mesa, AZ 85210 e-mail: info@uniquetek.com

Fax: 480-507-0867 - 2 - Rev. 20 04/15

Step 5: Install Micrometer Assembly

NOTE: Do not remove the plastic strip(s) jammed between the micrometer shaft and the threaded bushing. They are

there to provide friction to keep the micrometer setting from drifting during use.

a. Set the micrometer to a reading of 0.000.

b. Place the Powder Bar Insert in the Powder Bar. Make sure to orient the flat sides of the powder bar and powder

bar insert so they are both on the top side of the Powder Bar (photo below shows the bottom side).

c. Hold the Powder Bar vertically with the Powder Bar Insert at the bottom (minimum powder setting) and insert the

micrometer assembly down through the hole in the Powder Bar where the Powder Bar Adjustment Screw was

removed. Screw the ¼-28 adapter bushing into the Powder Bar Insert until the micrometer head is seated against

the end of the Powder Bar.

d. Check that the micrometer is still set to 0.000 and then position it

so the index mark is aligned with the pencil mark you made on the

Powder Bar during Step 1. (DO NOT FORCE)

e. If the Powder Bar Insert does not touch the end of the Powder Bar

cavity or if the micrometer head is not fully seated in the hole, pull

it out slightly and screw the ¼-28 adapter bushing a little more or

less into the Powder Bar Insert. Repeat until the micrometer reads

as close as possible to 0.000 when the Powder Bar Insert just

bottoms out against the end of the Powder Bar cavity.

NOTE: Do not worry if the micrometer does not read exactly 0.000.

The micrometer is only for indexing purposes, so zero is an arbitrary

number. However, it is better if it reads slightly greater than 0.000 rather than below 0.000 when the Powder Bar Insert

bottoms out, so the micrometer setting will always be a positive number. This way you will never accidentally confuse

–0.010 with +0.010. The Micrometer has been designed with more range than is needed so you will still be able to use

the full range of powder bar adjustment.

Step 6: Loctite®Micrometer Assembly Into Place

The micrometer head must be held in place using the LocTite supplied in the kit. Before applying the Loctite, make

absolutely certain that the powder bar is correctly assembled, the micrometer zero is adjusted and the micrometer

head index mark is aligned with the mark you applied to the Powder Bar in Step 1.

Note: Photo in Step 5 also indicates locations for Loctite application.

a. Twist off the top of the Loctite container and attach the application needle.

b. Apply 2 drops of LocTite to the ¼-28 bushing screw threads at the point where they engage the Powder Bar Insert.

Caution: Do not get Loctite on the small #2 screw at the very tip of the micrometer shaft!

c. Lift the micrometer head up 1/8th-inch and apply Loctite directly to the black base where it inserts into the Powder

Bar hole. Apply only enough Loctite to wet the micrometer base all the way around.

DO NOT APPLY TOO MUCH LOCTITE! Excess Loctite can drip down onto the micrometer shaft and seize the

micrometer. Use a cotton swab to remove any excess Loctite then apply a drop of oil to the micrometer shaft to

prevent any remaining Loctite residue from bonding.

d. Set the powder bar where it will be undisturbed while the Loctite cures. Clamp it vertically in a vice, prop it

vertically between heavy books or lay on a flat surface (with the micrometer head hanging off the edge) so that the

Loctite cures with the powder bar insert aligned with the powder bar. You may wish to add weight to hold it tightly

while the Loctite cures. It is important that the powder bar insert is held aligned with the powder bar while the

Loctite cures. Allow 24 hours for the Loctite to fully cure.

Step 7: Reinstall Powder Bar Post

The Powder Bar Post must be filed before installation to eliminate any contact with the micrometer shaft. Use a small

file, emery board or rolled up sand paper to file the inside surfaces of the Powder Bar Post where it touches the

micrometer shaft. This is very soft metal so only a few strokes should be required. There must be absolutely no

contact between the powder bar post and the micrometer shaft.

Note: The new style Dillon Auto Powder Measure (without return springs) does not need a Powder Bar Post after

the micrometer is installed. The setscrew used on the Belted Magnum and SL900 Shot Bar bar is also not needed.

Step 8: Install Micrometer Powder Bar in your Powder Measure.

Install the Micrometer Powder Bar in the Powder Measure by following in reverse the procedures used to disassemble

in Step 2. That is it!

UniqueTek, Inc. 540 W. Iron Ave., Suite 118 web: www.uniquetek.com

Phone: 480-507-0866 Mesa, AZ 85210 e-mail: info@uniquetek.com

Fax: 480-507-0867 - 3 - Rev. 20 04/15

How to Read Micrometer Powder Bar Setting

A micrometer or dial caliper should be on every reloading bench. But some times I get a little rusty if I don’t use my

micrometer frequently. So I’ve included these instructions just as a refresher. The photo below shows the Micrometer

Powder Bar set to a random setting of 0.332.

To read that setting;

1. First, find the largest whole number on the linear

scale. In this case it is 3.

Setting is > 0.3

2. Next, read the subdivisions on the linear scale. Each

sub-division is 0.025. In this case, one sub-division is

visible so add 0.025 to 0.3.

Setting is > 0.325

3. Now read the dial. Each division on the dial is 0.001.

The dial reads 7, so add 0.007 to 0.325.

Final setting = 0.332

That said, you might find it easier to read the settings as if

each whole number on the linear scale is 1.0 instead of 0.1. Reading the micrometer this way, the final setting shown

above is 3.32 instead of 0.332. I personally find it easier to read micrometer powder bar settings if I do it this way. The

“calibration curves” shown on the next page were created reading the micrometer settings this way. Either way will

yield the same results.

It is recommended that adjustments be made to the nearest 0.001 increment and not use settings between the lines

on the dial. This will have no significant impact on powder weight accuracy as the micrometer has much finer screw

threads (40 threads per inch) than the original powder bar adjustment screw (28 threads per inch).

The instructions for the Dillon Auto Powder Measure recommend turning the powder bar adjustment screw in 1/4-turn

increments when adjusting the powder charge. The micrometer has finer screw threads so the equivalent adjustment

is more than 1/4 turn. The equivalent on the micrometer is 0.009 increments on the dial. To keep it simple, we

recommend using 0.010 increments for initial powder charge adjustments and then using smaller increments as you

get close to your desired final powder weight. Also, the micrometer works in reverse compared to the original, powder

bar adjustment screw … turning the micrometer counterclockwise increases the powder charge.

Record the powder weight you obtain at each micrometer setting as you work toward your desired charge weight. This

data can be charted to give you a calibration curve (see page 4) for that particular powder. Using the calibration curve,

you can easily predict the micrometer setting that will yield a particular charge weight. Just dial the micrometer to that

setting and confirm the charge weight by weighing.

CAUTION: You must always confirm the charge weight with a powder scale, even when setting the Micrometer Powder

Bar based on data from your own calibration curve.

NOTE: As when making any powder bar adjustment, throw several “dummy” charges before measuring any. This will

allow the powder to “settle in” to the new powder bar adjustment and give an accurate reading.

NOTE: When changing from a very large to a very small setting, you will compress powder in the powder bar and

potentially overstress the micrometer threads. Cycle the press to drop powder, then make the adjustment while the

press handle is still in the down position. All powder weight changes should be made with the press handle in the

down position so that the powder bar is empty of powder.

Calibration Curves

If you reload a very wide range of charge weights with a particular powder, you can make a calibration curve for that

powder. Once completed, you can dial the micrometer to any charge weight you want by looking up the micrometer

setting from the curve. This will get you very close to the desired charge weight on the first attempt, greatly minimizing

the time needed to “dial in” the exact charge weight.

You can download a copy of the Calibration Curve Spreadsheet from the Micrometer Powder Bar Kit™ page

on our web site at http://www.uniquetek.com/site/696296/product/T1231.

CAUTION: You must always confirm the charge weight with a powder scale, even when setting the Micrometer Powder

Bar based on data from your own calibration curve.

UniqueTek, Inc. 540 W. Iron Ave., Suite 118 web: www.uniquetek.com

Phone: 480-507-0866 Mesa, AZ 85210 e-mail: info@uniquetek.com

Fax: 480-507-0867 - 4 - Rev. 20 04/15

Below is an example “Calibration Curve” for two of my favorite gunpowders. Due to the different physical

characteristics of various powders, you must make a calibration curve for each powder you use. You must also make

separate calibration curves for each powder bar size you use (Ex-Small, Small, Large and Magnum). As described

previously, I find it much easier to read the micrometer as if each major increment were 1.00 instead of 0.100. This

technique, although technically incorrect, makes reading the powder settings more intuitive.

You can look up the micrometer setting for any charge weight directly from your chart. But, if you have a computer and

Microsoft Excel, you can fit a linear curve to the data and get the equation for the curve. From that equation, you will

be able to quickly calculate the micrometer setting of any charge weight you desire!

For example, if I want 6.7 grains of Winchester 231, the equation (from the example calibration curve above) is;

Micrometer Setting = (6.7 –2.7368) ÷ 2.4708 = 1.60

So you don’t need a computer at your reloading bench. Once you have the equation, a hand calculator will do.

CAUTION: You must always confirm the charge weight with a powder scale, even when setting the Micrometer Powder

Bar based on data from your own calibration curve.

Since all calibration curves must be linear, curves can be generated with far fewer measurements (e.g. 0.00, 1.00,

2.00, 3.00, 4.00, 5.00) and still get a reasonably accurate curve with a lot less work. For maximum accuracy over a

short range of powder weights, you can make calibration curves that cover just the range of powder weights you

typically load, and measure at closer spaced micrometer settings. Always include one data point above and below the

maximum and minimum powder weights you will actually use.

CAUTION: The above calibration curves are supplied only as examples. Do not attempt to use them with your own

micrometer powder bar. Due to the slight differences in the zero setting from one Micrometer Powder Bar

installation to another, calibration curves for one Micrometer Powder Bar will yield slightly larger or smaller

powder charges compared to another Micrometer Powder Bar. Thus, if you have more than one Micrometer Powder

Bar of the same size, you must generate separate calibration curves for each one. You may wish to write a number

on the side of each Micrometer Powder Bar so that you can keep track of which set of calibration curves goes with

each Micrometer Powder Bar.

Disclaimer: UniqueTek, Inc. is not liable for damages or personal injury that may be incurred as a result of using this product in an improper way or in a

reloading press that has been improperly maintained or operated. It is your responsibility to ensure that your reloading equipment is properly assembled,