Looking to fix my ovaled holes in my 1975 Diamond plow bridial where the verticle pivot pins pass through, upper and lower. Can't get the plow bade or other pieces on my Bridgeport. Was thinking adapting a boring head to a Mag Drill. Or I might just find an annular cutter the size I need and machine up a center locating slug that fits snug in the original hole and it center drilled. Then put the locating slug in the hole and locate the center of the annual cutter arbor to the center drilled hole of the slug. Then cut my outer hole. Thoughts?
TJS
I've not seen a mag drill rigid enough for a boring head. I have bored holes with one but that was more line boring in that I used one of my line boring bearings to support the bar. Kind of like I did with my radial drill boring video.
[video=youtube;nMM_lJ7q6JY]https://www.youtube.com/watch?v=nMM_lJ7q6JY&list=UUlaADjT6nJnLUbkHUBJr5cA[/video]
Personally if you can get by with using a annular cutter it will be much faster. It's just not capable of making the hole as precise as a boring head.
[video=youtube;nMM_lJ7q6JY]https://www.youtube.com/watch?v=nMM_lJ7q6JY&list=UUlaADjT6nJnLUbkHUBJr5cA[/video]
Personally if you can get by with using a annular cutter it will be much faster. It's just not capable of making the hole as precise as a boring head.
I imagine you could use a setup with a mag drill much the same as Irish did with the radial drill and support bearing underneath (nice job there). Some guy out in OZ land used a bar between 2 bearings with a hand drill motor to repair a mini excavator & posted up on the Heavy Equipment forum about it (where there's a will..)
I do have a boring head that I can stick on a Van Norman 944 cylinder boring bar that works well for what it is.
Good luck.
Matt
I do have a boring head that I can stick on a Van Norman 944 cylinder boring bar that works well for what it is.
Good luck.
Matt
Are you saying the tabs are wollowed out? or the hole in the ram is?
If it's the tabs then you're going about it all wrong.
Mig or tig the inside of the hole and just carefully die grind it out until the pin fits perfectly...
I'd also consider adding another plate with a hole in it on top of the existing tabs.
If it's the tabs then you're going about it all wrong.
Mig or tig the inside of the hole and just carefully die grind it out until the pin fits perfectly...
I'd also consider adding another plate with a hole in it on top of the existing tabs.
You're over thinking it to some degree. I know it's nice to get back to original OEM, but it's not necessary, and you'll face the same problems over and over.
Use 1/2-3/4 plate, drill holes in the pieces to match a new pin, then weld the pieces of plate over the old holes.
To get better wear, switch to a cold rolled pin if it's a hardened pin in there now. Cold roll will wear to some degree where a hardened pin won't. It keeps your new holes from wearing too fast (easy to replace a pin a couple of times to one replacement of the cover plates). It's not necessary to have an exact match on the pin dia. wise, actually a bigger dia pin would wear slower.
Instead of stressing about finding exact center on the wallowed out holes, just use a full length pin (top to bottom) for alignment when attaching the cover plates, then cut the pin to the lengths you need for the final assembly. This way you're determining a new center, without all the headache. If aligned in this manner it will pivot properly.
Weld the cover plates so that the only welded sides are easily accessible for grinding off at a later date when you have to replace them. If it's not easily accessible, don't weld them all the way around. Maybe only on two sides. Doesn't take much weld to hold these in place.
Just hog out the existing holes to accept the new pin without any interference when you put the new plates on.
I know a lot of people think you need hardened pins for something like this. My thinking always has been that I'd rather the pin wear than the hole it's in. Cold roll will be MORE than adequate for the job at hand.
While sleeving will work, it's a PITA to remove the sleeves the next time you have to do this. Easier to grind off a cover plate every few years. AND a sleeve will have to have either a full penetration weld around the perimeter, or fillets on both sides of the sleeve if it's allowed to protrude through the plate where the hole is. There's clearance issues.
Use 1/2-3/4 plate, drill holes in the pieces to match a new pin, then weld the pieces of plate over the old holes.
To get better wear, switch to a cold rolled pin if it's a hardened pin in there now. Cold roll will wear to some degree where a hardened pin won't. It keeps your new holes from wearing too fast (easy to replace a pin a couple of times to one replacement of the cover plates). It's not necessary to have an exact match on the pin dia. wise, actually a bigger dia pin would wear slower.
Instead of stressing about finding exact center on the wallowed out holes, just use a full length pin (top to bottom) for alignment when attaching the cover plates, then cut the pin to the lengths you need for the final assembly. This way you're determining a new center, without all the headache. If aligned in this manner it will pivot properly.
Weld the cover plates so that the only welded sides are easily accessible for grinding off at a later date when you have to replace them. If it's not easily accessible, don't weld them all the way around. Maybe only on two sides. Doesn't take much weld to hold these in place.
Just hog out the existing holes to accept the new pin without any interference when you put the new plates on.
I know a lot of people think you need hardened pins for something like this. My thinking always has been that I'd rather the pin wear than the hole it's in. Cold roll will be MORE than adequate for the job at hand.
While sleeving will work, it's a PITA to remove the sleeves the next time you have to do this. Easier to grind off a cover plate every few years. AND a sleeve will have to have either a full penetration weld around the perimeter, or fillets on both sides of the sleeve if it's allowed to protrude through the plate where the hole is. There's clearance issues.
Guess a lot of you guys don't own plows. As DSW said. These pins bend no matter what. They are hardned. The pin is not the issue. The holes wollow out. You all gave some good ideas. I am going with the rotobroach idea. Machine a shoulderd bushing and weld it on top(almost like a plate welded on top as suggested). This way I can always grind the welds off if the bushing gets messed up. If you look close at the pic I posted someone welded washers in an attempt to stop the excessive movement. Kind of like the plate idea.
Thanks again.
T.J.
Thanks again.
T.J.
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