RCBS 304 scales

[MJR]

Can these scales be tuned? Just wondering if its possible to squeeze a little more accuracy from them.

[John MH]

Only person in the UK I could think of that may be able to tune them would be Allen Edwards (1066), otherwise its Scott Parker in the USA.

 

You cannot actually make them more accurate by tuning. Tuning makes them more sensitive (so that they respond to a single kernel of powder) and 'repeatable' so that you can be confident that each charge is the same weight (to within a tolerance) but that still relies on using a 'Mark 1 Eyeball' to check the alignment of the beam. They, like all scale and balances, can be effected by air currents although most beam scales are magnetically damped to reduce the effect.

 

BTW RCBS 304 scales are quite rare and attract a premium price when sold secondhand.

[MJR]

Thanks John. Watching your progress with the scales and trickler I wondered if there was more to squeeze out of the 304. I find it accurate and get reasonable SD but not comparable to your results. I use the camera on the mobile to view the needle on the scale.

[stu47]

This is my setup for the 304.

 

I found that my scales where a little slow to "respond" to kernels dropped so I stripped them down cleaned the main pivot bearings (made of glass) with nail varnish remover and sharpened the pivot (a triangular shaft) using a 00 oil stone. I repeated this with the hanging basket pivot and bearings. I cleaned the magnets (at the pointer end) using cello tape and reassembled ensuring everything was central and in line. Whilst at the pointer end i attached a sewing needle to make seeing the pointer lines easier and stuck some foam above and below the pointer so it cushions the blow when removing the tray. The difference is incredible and does indicate a single kernel when dropped and works a treat with the Target Master (with the reduced diameter nozzle attached). I drop a measure of power that's 0.5 grain under (now with a Lyman Gen 5 not the Lee Powder Drop in the photo) what's required then use the Target Master to trickle to the required load. It's not the fastest process out there but it's ridiculously accurate and very repeatable. Before each use I connect a length of wire to it (crock clips) and attach the other end to the radiator - this earth's it out and removes any built up static - this is then removed before I start.

 

Hope this helps.

 

Stu.