How to adjust alignment pins

Kevin Stenberg

Well-Known Member
#1
I have an MP 358-640 HP Brass mold. And the pins are placed too far into the mold so they do not make contact with the apposing contact recess.
The tools i have on hand to adjust the male pin. I have c-clamps. and a bench vice. And that is it. I just remembered i have a drill press i could use like an arbor press.
The base of all 4 pins are flat, and recessed about 3/16ths below the outer face of the mold.
 
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fiver

Well-Known Member
#3
punch and hammer here too.
you could use the vice and a pin and turn them in a touch.
don't go too far, and don't do it unevenly.
you'll hold the mold open or make the cavity's uneven.
 

Ian

Well-Known Member
#4
First, clamp the mould blocks securely together in a vise, then whack the pins with a 16 oz. hammer and flat-face punch. The pins will tend to jump more than you want when they finally move, having the mating pin clamped in place for a positive stop will hopefully prevent that.

If you havent cast with it yet, I would do that. The hp pin guides do a lot of the alignment task, and for some reason the alignment pins always seem to engage more tightly when the blocks are up to casting temperature.
 

fiver

Well-Known Member
#5
not only that but the dissimilar metals will have different expansion speeds.
it's easier to move a steel pin in an aluminum mold if it's heated up but not heat soaked so that the steel starts expanding too.
you have to be careful about moving the pressed in female pins too so I usually do the aluminum ones open faced and padded.
even the mehanite molds have a little different expansion rate than their pins.
 

Kevin Stenberg

Well-Known Member
#6
Thanks all! I used Ian's instructions. And got good results.
The reason the question was asked. I had a NOE mold that the pins had moved during a casting session and wouldn't stay in place. I had adjusted them and the adjustment would never stay it kept moving.
 

Bret4207

Well-Known Member
#7
I had a NOE mold that the pins had moved during a casting session and wouldn't stay in place. I had adjusted them and the adjustment would never stay it kept moving.
That sounds like a job for a well placed center punch at the base of the pin. Figuring out just where that is the trick and then it only works if the metal is shallow enough there to displace in the pins bore. A set screw would be another option. I don't know of a loc-tite type compound that will handle the temps we cast at.
 

Ian

Well-Known Member
#8
Bret, in general, sodium or potassium silicate will do the trick. Buy a little 4-oz bottle of stove cement and it will glue metal together and hold it to at least 2,000°F.
 

Brad

Administrator
Staff member
#10
Sodiu silicate, AKA water glass. This is the binding and hardening agent I. The stove cement. That grittiness is the clay/sand they added to give it some body.
I worked in a pharmacy while in school and we sold a fair amount to people who used it to seal radiator leaks.
 
#12
One needs to remember another adjustment may be in the future if we get the pin 'glued' in too well...... I prefer to dimple punch or knurl the pin a little if I don't like the fit..
I adjust different too. I start by 'feeling' the clearance or 'rock'. Them I mic the pin protrusion off the mold face... I tap it out some as mentioned (a little more than needed by a couple thousands) Then I press it back in precisely with a little brass faced c-clamp. I can get it a thousandth at a time this way without a trial and error fitting method.

Pete
 

Ian

Well-Known Member
#13
I'm talking about the clear sodium silicate sold in little 2-oz. bottles as a stove gasket adhesive, not the patch cement which is a putty of sodium silicate and bentonite and fine silica sand. Rocksett muzzle brake cement is a mixture of potassium and sodium silicates and is an excellent high-temperature threadlocker, the only way to defeat it is to saturate it with water for days. It also takes several days to dry out enough to "set", since there is no anaerobic chemical reaction as with the methyacrylate esters in most threadlocking compounds. Rocksett costs about $20/oz from shooting supply houses, you can get the small bottles of stove gasket adhesive at the homestore or hardware store for $5 and it works just as well.
 

Bret4207

Well-Known Member
#14
Aha! Water glass. Okay, now I get it. My bad. I was picturing stove CEMENT. I haven't seen the little 2 oz bottles you speak of Ian, but I may look now that you mention them. My wood stove door gasket is constantly falling out. In fact, it's disappeared recently, so when I get a new one I'll take a look for the "glue".