There has been a lot of talk over the years about how to repair the infamous "Arc-of-Shame". I had some tables that were pretty bad. My documention has some holes in the process. I just decided to experiment on some of the ones I have to see if I could improve them. I figured...what do I have to loose. These are all off of machines that went on to be restored or are in process now.
Here is what I ended up with.
[size=14pt]Example #1[/size]
I started with this table from a Delta 14" DP. I have some CI rods that are for repairing cast iron with a tourch. They are used just like brazing rods except these require much higher heat to melt/fuse in. As you can see in the picture below, the results left a lot to be desired. It takes way too much heat. I could have heated the whole table up first which probably would have helped.
A few weeks later, I thought I would give a try welding it up with the MIG welder. The results were quite a bit better.
The top is just ground down with a disc grinder. I thought that this method was worth further experimentation.
[size=14pt]Example #2[/size]
This is the Walker-Turner 900 table as it was, once I managed to remove it off of a very tight and rusty column. As you can see, it is pretty well drilled up and would be a rather ugly distraction on a restored machine. I did not clean up the table at all before welding. One of the results of not cleaning up the metal first is it creates a lot of voids/pits in the weld.
[size=14pt]Example #3:[/size]
This table is off of a Delta 15" and was severely broken. I was going to scrap it but it drill mark free and a challenge so I gave it a shot. I clamped all the pieces around a short piece of column to maintain the column hole size and shape. I V'd the cracks out and started brazing it. I did one crack at a time and then ground out another V and brazed that crack. I continued the process until it was completed.
The table is fully functional and went on to a restored drill press.
[size=14pt]Example #4:[/size]
I had to post the picture of the drill press contraption that the next table was on. I am not sure what it was for but my best guess is that it was some sort of production screw feeder.
Notice the holes and slot in the front of the table.
I used an angle grinder and countersink to clean all around the areas to be welded. I made small plugs to fill the holes. The plugs were made to sit about 1/8" below the surface.
I was going to grind everything even but the underside was taking too much time so I decided to leave it since it is on the bottom.
[size=14pt]Example #5:[/size]
I don't have any pictures of this method but it works well on isolated holes.
Drill and tap the hole for a pipe plug. Soft iron plugs work well. Use JB-Weld or similar to adhear the plug into the newly tapped hole. When the adhesive is hardened, the plug can be ground flush with the table surface. This makes an easy and almost invisible repair.
Things I learned.
1. All rusty areas need to be cleaned of corosion before any welding is done.
2. Don't try and fill large areas with weld. Make plugs to fill the holes first.
3. Work small bits at a time and don't try and do all the welding at one time. Weld some and let it cool and then weld some more.
4. Weld the plug around the edge so that you are attaching the plug to the cast iron first. Let it cool and then fill the rest of the area over the plug in the weld ring you made in the first step. If you work in small amounts and only heat the part minimally, there is far less cracking from the shrinking weld pulling away from the stressed interface of the CI and the weld filler material.
5. If you have some cracking after you have ground the patch flush, you can V out the crack with a small grinder and re-weld it. It doesn't seem to crack on the re-weld.
I hope you found this little pictorial helpful and informative. Now I need to come up with a way to regrind the machined surface.
Charlie W.