My two worst experiences cleaning the throat and changing mouthpieces on a Linotype.
The first was in Daytona, FL. I removed the MP by using an impact wrench to get all of the 13 screws loose. After removing the screws I found that the space behind the MP looked just like it still had a MP on it. There was nothing but tiny holes for the metal to come out. I actually had to use a ½” drill bit to drill the dross so that I could get throat saw started. I sawed for approx an hour before getting the throat clean enough.
The second was in Atlanta, GA and 12 of the 13 screw heads broke off and I had to drill and tap the holes back out before I could install a new MP. The throat on this one was very clean and I had to do little sawing.
This is my procedure for doing this job. The machine should be hot for this procedure.
1. Drop the first elevator down onto the vise cap.
2. Open the vise frame to the second position. Open until it stops and then pull the pin at the bottom and drop it to the second position.
3. Release the mold disk so it can be pulled out.
4. Pull the mold disk out a little then remove the long screw that the ejector guide slides on.
5. Remove the long screw and the ejector guide.
6. Pull the mold disk and ejector mechanism all the way out and lay it aside.
7. Remove the mold plate above the mold disk.
8. Using the Linotype jarring tool, part number ( F-2860 ) and a medium to large hammer, hit the head of each screw 2-3 times. This should loosen the dross built up around each head.
9. Take a medium to large screwdriver and try to turn out each screw. Be sure you have a screwdriver that fits the slots well. A lot of times the heads will get messed up by using the wrong size.
10. If any of the screws do not turn then go back to Number 8.
11. If the screws still do not turn out there are two methods I have used to get them out. One – use an impact driver to break them loose. Two – Use an acetylene torch to heat each head to a cherry red and then use the screwdriver to remove them.
12. If, you break the head from a screw then you can use a drill and drill it out. There is a set of jigs made so that you can get the holes straight. Then re-tap or clean the threads with a ¼-24 tap. Yes, it is ¼” by 24 threads.
13. Next I cover as much of the vise frame as possible with rags and also put a metal pan or bucket under the front of the pot mouthpiece opening to catch the dirt that you clean from the crucible.
14. Now you use the throat saw part number ( F-4236 ) to saw out the throat, putting pressure and pulling the dirt out. Also, twist the saw blade so that you can get the top and bottom of the throat as clean as possible.
15. After you get the throat as clean as you possibly can, place a metal container under the throat and using gloves, long sleeves and safety glasses, push down on the plunger to drive out any dirt and see if the metal is flowing smoothly. This needs to be done VERY CAREFULLY as this metal is 500+F.
16. For this next step you will need a NEW sharpening stone. I use a two ¾” thick by 2” wide by 6” long stone I get from Ace Hardware. It has a coarse side and a medium to fine side. To get the stone ready, lay it on the top of the hot crucible and let it heat up, then put it into a can and cover it with 20 – 30 weight oil so that it will soak into the stone.
17. When the stone has soaked in some oil you use it to clean the Crucible face and get it straight so that the NEW M.P. will seal when you install it.
18. Also, stone the back of the M.P to make sure it is straight.
19. When you install the New Mouthpiece you need to use New Screws.
20. When you install the New Mouthpiece you start by putting the screws into the middle, one at the top and two at the bottom right under the top one. Then you put two on each outside hole. Tighten these hand tight and let the whole works heat up to the crucible temperature.
21. I use a high temperature anti-seize and starting in the center dip a screw and place it in an empty hole in the center and tighten it, then working your way towards the outside. After all screw holes have been filled remove the first ones that were inserted and dip them in anti-seize and replace them. Starting in the center and working outwards tighten all screws as tight as possible by hand. Sometimes I use an impact driver and tighten them a touch more.
22. Now I would make sure the metal container is still under the MP. I push down on the plunger again to make sure metal is coming out all holes cleanly.
23. Now is a good time to clean the mold disk and ejector mechanism before installing them back into the machine.
24. Then install the plate on top of the mold disk, the ejector guide and long screw.
25. Lock the vise frame back into normal position and put everything back in operating position. Cycle the machine back around to normal. Leave the plunger out for this step so you do not get a squirt.
26. Open the vise frame back up and pull out the mold disk. Then take the stone and stone the front of the M.P. Next do a lock-up test using red lead or whatever method you prefer. Adjust the pot for a good lock-up and you should be back in business.
Not a job for the faint of heart, but sometimes it is necessary.