The Home Machinist!

John, why were you tapping the head?

Fred_V wrote:John, why were you tapping the head?

I dont have the drawing in front of me at the moment, but if I remember correctly, that is for one of the six studs that holds the whole pump together. Since it's below the main valve chamber that stud is threaded into the top casting rather than passing through it.

By the way, this is NOT a wife approved method of removing a broken tap!



Just noticed something... the alum I'm using is McCormick's alum from the grocery store, which is ammonium aluminum sulfate. The research I did on the web referred to potassium aluminum sulfate. Hrm, will this still work to dissolve the HSS tap?

Got a little more done this evening. Since I'm still waiting on my broken tap to bubble its way to freedom, I started on the steam cylinder.


Chucked up in the 4-jaw ready for facing...


... and boring.


I'm very happy with the surface finish on the bore. Probably the smoothest machining I've done yet and I'm within 0.0015". I was too afraid of screwing it all up to get that last bit, but I'm sure I'll be ok

Came home from work and took the casting out of the crock pot where it's been stewing in the alum for the past two days. It had stopped bubbling from the tap and appeared that all that had happened was the broken tap was discolored.

I took a paper clip and poked at the broken tap ... it was MUSH! Brown sludge. Cleaned out the hole and there's still just a tiny little bit of the tap in the bottom. Back in the solution to finish the job!

John if you would get some of those wore out Smile dental pricks from your dentist.and poke a little once in a while once it starts to break down a little of that helps it penetrate and will work much faster. At least it works for me. Whitey

like i suggested - just wait and do not be in a hurry....

Steam cylinder, drilled the top end for bolts and the steam passage to the bottom end of the cylinder:


Houston, we have a problem:


Guess it's time to make a sleeve to press in... or just give up on this stupid thing. The steam passage is nice and straight until about 1/3 of the way down, then it curves ever so nicely toward the cylinder wall. Fantastic.

I've had that happen to me too. What causes it?

Hard to tell from the pic, but the passage is notched into the bore at the
bottom anyway. If the present notch is clear of the piston O-Ring at
bottom stroke, it may be ok. The spacer register is also in the bore, I think.

Fred_V wrote:I've had that happen to me too. What causes it?

One cause is if the casting is not solid, the drill will drift to the porous spot. Some times you can feel the difference when you hit a porous spot.

Regardless, sharp drills help to keep the drill from drifting.

Regards,

Doug

drilling with a short spot drill or end mill also helps. keep the drill as short as possible. carbide also is better than hss.

as i said early on, i did 2 of these, and all the castings were porous. many had to be replaced to be usable