Lyman split washer and RCBS pins corrected

[ohland]

Today I grabbed my RCBS 45-300-FN to make some boolits. Had a slight delay, the block halves would not close totally. Well, the mould was new to me, so I boiled it out. Helped some, but I saw some remnants of a "stain" on the blocks. Went to the basement, set the RCBS on concrete to cool it faster, then rummaged through my stash until I pulled out a Lyman 375248. Pro-Melt is full of softer lead, might help the .375 with plain base...

Another issue, the split lock washer was, well, a split lock washer. Digging into the sprue plate. Took the lock washer over to my little friend, the belt sander, and knocked the sharp ends off. Reassembled the Lyman mould.

RCBS was only warm by now. Took a bronze brush to the mould face near the pins. I recognized the grey "staining" as mould prep. Brushed off both halves, try fitted. Still high by the pins, but tight away from them. Whippied out my calipers, measured the original height of pin and block half as .765, found a 7/32 punch (used to tap pin out if over-corrected), and got my 6oz brass hammer.

A little futzing, you use a smart rap to move the pin, but it won't take more than wrist and forearm movement. A bit back and forth on one pin, set both pins to .760, now the halves close with no light. It doesn't take much, in this case only .005 and the mould went from light between the halves and the blocks canting from the pins to a solid fit.

IMHO, mold prep should not be used on moulds.

[WALLNUTT]

Mould prep moved the pins?

[ohland]

Mould prep moved the pins?

And global warming ate my homework. I don't see even gross contamination of a mold face with mold prep moving the pins. To adjust them works much better if you hit the pin directly in-line with it. Mold prep IMHO would build up pressure (and an angled downward force) against the sides of the alignment pins.

Mould prep was built up some around the base of the alignment pins. That in itself was probably not the cause of the blocks not fitting closely, but it didn't help. The pins were higher than they needed to be and when placed together, the blocks stood out a wee bit on the pin end of the blocks. From the looks of the "staining", it appeared the mold prep was wiped off, but not thoroughly.... Think of car lock lubricant. Ever see the trail of graphite where the excess leaked down? It is not really "staining" but when it dries, it takes a little work with 409 or some sort of a solvent (WD-40!) to easily clean it up.

Cleaning the faces and around the pins got the split between the halves smaller. Tapping the pins in .005 got the halves to fit.