Rebuilding a worn-out “dog” on C & P 8 X 12
The counterbalanced cast iron piece that rotates the ink disk is worn on my press —- so worn that the disk sometimes doesn’t rotate as it should, causing light impressions. It appears that the “dog” (I’m pretty sure that is the term for it) was worn out once before, and someone drilled a couple of holes through it to build up the worn-out spot with a piece of steel and two rivets. Now that part is worn from use. Are replacement dogs available, or if I should grind the rivets off and put another piece of metal in? Thanks.
I’ve never seen a replacement dog before…. but I have seen a number of repaired ones. The repair that seems to work the best are to take it to a good welding shop, and have them build up the worn face about 1/4” (or more if needed) and then regrind it until it engages the disk. If the pivot is also worn, it’s a fairly simple matter to drill it out larger and press in a bushing.
The steel plate riveted to the cast iron is made to be replaceable. Grind off the rivet heads, punch out the rivets, and either rivet or bold a new metal plate onto the casting. If you’ve never done any riveting you may want to use bolts and nuts.
Make a copy of the original plate. You should be able to get a good idea of the original size and shape with what’s remaining of the original. Mild steel is easy to get, easy to work and will last longer than your use of the press. You may have some around the house. I wouldn’t be too concerned with the exact thickness, just come as close as you can.
Mine is worn also but not enough to replace yet. This is not a difficult repair and you should be able to do it at home.
Rich
Rich — I see exactly what you mean. It won’t be a big deal to just replace that little plate. I don’t want to risk breaking the casting, so I’ll use bolts or soft rivets.
Winking Cat — You make a good point about the pivot hole. It is so sloppy that it definitely could use a bushing to tighten things up a bit. I hadn’t even considered that.
I appreciate the good advice from both of you. So does the C & P 8 X 12, which is still going strong after 102 years. I’ve had it since 1975.
Kevin
All done! Instead of rivets, I used two brass bolts and nuts. Replacement will be easier the next time around, probably in 23rd century.
This is a great project for jbweld. Just clean it up and it works like a champ!