I’m trying to keep the momentum going, really I am. Over the last couple of days I got some work done on the side plate. The last post had me with the welded up, wavy and bent,skid plate. Now i had to mount it under the van. I didn’t think long and hard, but this is what I came up with.
A bit of 1″ X 0.25″ stainless flat bar cut up into 5 pieces, nominally 2″ long. Very nominally as I used a Zip disk in an angle grinder and I am notoriously bad at cutting a straight line.
As each bit was more or less 2″ i marked out hole locations from one end. I used a blue Sharpie as lay-out dye. You can barely see the scratches of location the hole positions.
I feel presumptuous to lecture on how to do this kind of thing. I really am a ham fisted metal worker. I say that with no false modesty because I have seen what real metal workers can do. But allow me to go through the steps I take and maybe some of you might find something I say useful.
I scratched out the hole locations using my digital callipers. Then I centre punched on location using a cheap optical centre punch purchased from Lee Valley, direct link here. Then I like to make the punch mark a little larger with a regular punch. After that I drill pilot holes using a small bit, something less than 1/8″. The reason for that is the thin bit catches and hangs on to the punch mark better than a larger sized bit. I have the workpiece on the drill press table held in my hand. Allows the workpiece to move around a bit to get aligned. With a small bit there is little chance the drill will spin the workpiece around and gash your hand. With the size of holes I am drilling here, the next drilling step is the full sized hole. I’m drilling for a 1/4″X20 tapped hole and so I would be using a #7 drill bit (or something like 5.01mm). I put the part in a drill press vice for this drilling.
Now I try, in this blog at least, to avoid absolutes. But I am telling you now something you should heed. When drilling in stainless steel your drill bits have to be sharp and of good quality. Really, any other bits are just the road to perdition. What ever country of origin you like your bits to be from, buy the best you can. I think at one time nothing could beat US made made twist drill bits. But there are excellent bits from Australia, the UK, and Europe. Price is the discriminating factor, buy the most expensive you can find. It really is false economy to buy cheap bits (unless all you drill is wood).
A good resource for basic and advanced metalworking is Mrpete222 on YouTube, here is the link. And learn to sharpen your bits, might take some time, and god knows it took a good time for me to learn, but you can freehand sharpen bit larger than 1/8″ with good results. When drilling stainless a sharp bit is mandatory. If you see the bit is not cutting stop immediately and change out bits or sharpen. I use cutting oil, the sulphated kind, when machining stainless, I’d say it was mandatory to use cutting oil unless your only going through thin stock and then heading right over to the TIG welder and don’t want any contaminants.
Enough of the lecture, back to the project. The holes drilled then on to tapping. Same advice for taps, buy the best you can, cheaper taps work ok in soft metal, but in stainless and the like you need the best quality.
Poor pic of tap starting in hole.
Then i held the parts in the vice and wailed on them with hammer to make a slight bend.
The threaded stainless tabs connect the new plate to the existing propshaft plate. I had to make the holes in both plates elongated to give me wiggle room to get things in place. And remember the new plate is curved and needed a bit of persuasion to get in place. I snapped this pic tonight, in the dark. The vertical part of the plate has not been fixed to the frame rail, it needs to be pushed up about an inch. but believe it or not, as is, it is quite secure and stiff.
I’ll get better pics tomorrow when i fix the outboard side to the frame rail.