Repairing egged out hole

[dante2]

I have a pair of brackets that are close to 20 years old and 640+ hours of service on a mower deck. The bracket is discontinued and unavailable in this universe. The hole originally was 7/8" and accepted a bushing and bolt through it. My only option is a repair of the oblong hole. Can I use a 7/8" brass bushing and fill the gap back in with a mig welder? My plan was flat copper on the table and clamp the bracket over that. Then clamp the brass bushing to the original intact edge and fill the oblong gap. Am I going to have a problem with the brass sticking? Any thoughts or suggestions are greatly appreciated. TIA

 

[cvairwerks]

Just weld the entire hole up and then redrill. Way faster and easier.

 

[bwringer]

I think you'll melt the brass bushing, if you're talking about welding with the bushing in place.

I'd just locate the center as best you can, then fill the hole with weld and re-drill.

To keep the drill bit on track (drilling through weld can be, er, interesting), perhaps drill a 7/8 hole in a hunka steel plate, tack weld it on, then use that as sort of a drill guide. (You could also start with a smaller hole like 1/4" and work your way up from there; might be easier.) And/or if there's room in the mechanism, maybe you could leave the doubler in place after trimming and welding it properly, and maybe end up with a much sturdier part.

 

[The Cobbler]

The hole originally was 7/8" and accepted a bushing and bolt through it

are you able to weld a nut to the flange and then thread the bolt with the bushing in place?

 

[dante2]

I think you'll melt the brass bushing, if you're talking about welding with the bushing in place.

I'd just locate the center as best you can, then fill the hole with weld and re-drill.

To keep the drill bit on track (drilling through weld can be, er, interesting), perhaps drill a 7/8 hole in a hunka steel plate, tack weld it on, then use that as sort of a drill guide. (You could also start with a smaller hole like 1/4" and work your way up from there; might be easier.) And/or if there's room in the mechanism, maybe you could leave the doubler in place after trimming and welding it properly, and maybe end up with a much sturdier part.

Unfortunately that's it on the thickness. Looks like a fill and drill job. Just time and I have plenty of that. Thanks for the help now I need to get a 7/8" bit.

 

[dante2]

are you able to weld a nut to the flange and then thread the bolt with the bushing in place?

I don't think so. This is the bushing and the 2 brackets are stacked with the bolt thru the deck. No real tolerance for anything else since everything little thing effects the belt angle.

 

[no704]

Unfortunately that's it on the thickness. Looks like a fill and drill job. Just time and I have plenty of that. Thanks for the help now I need to get a 7/8" bit.

Just use a step drill.

 

[RoninB4]

Unfortunately that's it on the thickness. Looks like a fill and drill job. Just time and I have plenty of that. Thanks for the help now I need to get a 7/8" bit.

-Drilling a partial hole, an interrupted cut, is going to be a bit sketchy with a drill press. The excess weld/braze on the worn side will tend to push a drill over to the other side. It will either snag, catch, of go off center even if the part is clamped to the table. Do you have a milling machine or a lathe? You do what you want to but you're intent on using a drill press I'd strongly suggest using quill feed control in the order of .007 down-feed on a peck cycle. If you use a twist drill it can snag, break the drill, mangle the bracket, and/or launch the workpiece. If you're using steel for filler your cutting speed will need to be fairly slow (making it more snag prone) or a carbide cutter will be needed. This is all the more reason to do this in a mill or lathe. Better results, better control, more cutter options this way.

If you were closer I'd have you bring it over and do it while you watched/learned. If you're going to use a brass (or other material....) bushing then now would be a good time to plan of employing a replaceable bushing into the design for next time. Wear properties for brass aren't very good for some things. Post your intentions.

 

[Beerhippie]

I'll bet @KwikFab could reproduce that. Maybe he'll pitch in.

 

[jbltwin1]

Weld up the egged out part and get the router bits out and re-round it. Or weld the hole up and re-drill. I've done both. Actually, just did something similar on JD pivot bracket. It had a 1/2" steel boss on a 3/16" or so bracket with a .502 hole for a shouldered bolt. . I elected to just cut the boss off, center bore a 1/2" hole in a piece of 1" stock. Cut it roughly to length and then turn it square and length on the lathe. Stick reamed it an extra .002 for slip clearance and them MIG'd it on bracket. Easy peasy.

 

[KwikFab]

I'll bet @KwikFab could reproduce that. Maybe he'll pitch in.

I'll check the thread tonight or tomorrow!

Literally getting ready to head out of state (NV).

 

[Caneil]

Could use a piece of graphite rod that's the diameter of the hole you want. Put it where you want the hole, weld right up against it. Even if one has to break it up to get it out, the diameter and location are still right.

 

[rsanter]

You use copper as a resist to mig welding, not brass

just lay some weld in the hole where it got oblonged and then die drinker to make round again

 

[rlitman]

...now I need to get a 7/8" bit.

I strongly suggest not doing that. The step drill is your friend here. Especially when it comes to situations like this, step drills with their long circular wedding cake stair steps drag on the edges of the hole, keeping the bit well centered and the hole round. A regular twist drill is going to bite into the edge and that's going to **** when you find out that the welded edge goes from hard to soft all over the place. You'll end up with a real ugly hole, if it doesn't break the drill bit or throw your part.

Or, if you don't mind a perfect fit, welding just the worn side and then die grinding back to round is an option.

 

[dante2]

I got the worst one done. I'm pretty sure the 3/4-7/8 is shot on 2 different step bits. I also found out my drill press really isn't up to the task either. The other bracket isn't as bad so I think I'm going to add a little to the low side and grind it into shape. Any recommendations on a good bench drill press?

 

[HoosierBuddy]

Any recommendations on a good bench drill press?

If it was me and I had to have one fast, I'd probably at least try to order this Wen, which appears to be kind of a 12-inch Jet clone, because of all the features and I have bought a few Wen items, such as a dust collector, and have found there stuff to be surprisingly well built.

https://www.amazon.com/dp/B0DQ9F3DX8?tag=atomicindus08-20

If I had the time? I'd scour FaceBook marketplace or Craigslist and find a nice US made one from the 1960's to 1980's. Even the consumer ones like my old Craftsman are well built. Although they lack features like variable speed drive or digital readout or laser targeting....they will absolutely drill holes in anything you put under the bit (including the table if you're not careful). Can be found for not a lot of money and will outlast us all.

 

[rlitman]

I got the worst one done. I'm pretty sure the 3/4-7/8 is shot on 2 different step bits. I also found out my drill press really isn't up to the task either. The other bracket isn't as bad so I think I'm going to add a little to the low side and grind it into shape...

In theory, you can pretty easily use an angle grinder to bring back the edge of a step drill and remove the rounded corner back to sharpness. In practice, step drills are so cheap at HF that I'll admit to never bothering with this.

But yeah, cutting through a mix of weld and heat affected steel is hella hard on any drill bit. At least a step drill makes it a moderately controlled experience. Good luck with the grinding. I'd use a 1/4" solid carbide (and a full face shield, because the needles a carbide throws are something awful), and hold on tight, because the one thing you absolutely MUST avoid while die grinding inside a circular hole is the grinding climbing away and pulling you around the circle. That gets violent fast. Having a smaller cutting edge (one that has a lot of space in the hole) helps.

 

[dante2]

If it was me and I had to have one fast, I'd probably at least try to order this Wen, which appears to be kind of a 12-inch Jet clone, because of all the features and I have bought a few Wen items, such as a dust collector, and have found there stuff to be surprisingly well built.

https://www.amazon.com/dp/B0DQ9F3DX8?tag=atomicindus08-20

If I had the time? I'd scour FaceBook marketplace or Craigslist and find a nice US made one from the 1960's to 1980's. Even the consumer ones like my old Craftsman are well built. Although they lack features like variable speed drive or digital readout or laser targeting....they will absolutely drill holes in anything you put under the bit (including the table if you're not careful). Can be found for not a lot of money and will outlast us all.

Plenty of time and the Wen 4212 still works but it took a beating. This one just doesn't have the amperage for big projects.

 

[dante2]

In theory, you can pretty easily use an angle grinder to bring back the edge of a step drill and remove the rounded corner back to sharpness. In practice, step drills are so cheap at HF that I'll admit to never bothering with this.

But yeah, cutting through a mix of weld and heat affected steel is hella hard on any drill bit. At least a step drill makes it a moderately controlled experience. Good luck with the grinding. I'd use a 1/4" solid carbide (and a full face shield, because the needles a carbide throws are something awful), and hold on tight, because the one thing you absolutely MUST avoid while die grinding inside a circular hole is the grinding climbing away and pulling you around the circle. That gets violent fast. Having a smaller cutting edge (one that has a lot of space in the hole) helps.

They were pretty cheap bits thankfully so no great lose. I've played the chip game more than a few times, they get everywhere. Anytime I grab a grinder out come the gloves and face shield. The grinding should go a lot faster since I don't have to add much to the second one.

 

[RoninB4]

I also found out my drill press really isn't up to the task either.

-A drill press, no matter who makes it, is entirely the wrong machine for the job. You've already found this out.

Any recommendations on a good bench drill press?

-Nothing for a reasonable cost except a used square column mini-mill for work like that. The round column mills may work but I consider them a lesser design for milling. Both will have the rigidity that you'd want, a drill press (even a large radial model) won't be capable of holding the cutter solidly due to side loading. A drill press is only capable of up/down loading, don't even consider one of those awful graduated X-Y tables for milling with a drill press.

 

[dante2]

-A drill press, no matter who makes it, is entirely the wrong machine for the job. You've already found this out.

-Nothing for a reasonable cost except a used square column mini-mill for work like that. The round column mills may work but I consider them a lesser design for milling. Both will have the rigidity that you'd want, a drill press (even a large radial model) won't be capable of holding the cutter solidly due to side loading. A drill press is only capable of up/down loading, don't even consider one of those awful graduated X-Y tables for milling with a drill press.

I don't have space for another machine at this point. This was a one off thing that likely won't have to be repeated. I work more with wood and cars than I do metal fab. Thank you for the info though.

 

[danielbuck]

-A drill press, no matter who makes it, is entirely the wrong machine for the job. You've already found this out.

eh, I'm pretty sure an annular cutter in a drill press would have no problem doing this. I've drilled holes 1/2 off center of an existing hole with a drill press and an annular cutter no problem.