oblong holes need to be round?

paul · Mar 2, 2012

So, if you have a bunch of worn out holes you want to drill out & put bushing in, how do you drill the holes? I'd think a regular drill bit would catch & shatter or otherwise be bad thing.

Think I've managed to do this a time or 2, but looking at my planter with 15 rows x 4 x 2 straps to drill through, and I see an old dog better learn a new trick?

--->Paul

edward will · Mar 2, 2012

Hi I would use a tapered reamer. no sweat. ed will

Old Roy · Mar 2, 2012

are the straps off, and are the holes evenly spaced? could make a jig out of another piece of a little heavier materal and bolt it centered and use a drill press ?

Paul from MI · Mar 2, 2012

Most of the time all the wear on a hole will be on one side, not evenly distributed. If you just drill it out bigger and put in a bushing the drill will follow the worn hole and the resulting hole will not be in the same location as the original one. In order to maintain the original location you either need to use a drill guide bushing clamped in place to the correct location, or mount the worn part in a milling machine and use an end mill or boring bar to enlarge the hole on it's original location. If location isn't critical, then just drill and ream for a bushing.

old · Mar 2, 2012

I just did one yesterday. You need a bot that is just a tad bit bigger then the widest part of the hole and it works well if you take it slow

Ellis Kinney · Mar 2, 2012

I realize most people don't have a milling machine, but a milling machine cutter bit would be best because the part can be held more securely and drilled more accurately. Ellis

Russ from MN · Mar 2, 2012

Use another piece of metal c-clamped on as a guide.

evilboweviel · Mar 2, 2012

this type of bit with a guide (wood or metal) clamped to the piece to be drilled
guide is a pice that you drilled with the bit first
have done it freehand without a guide just not as accurate
good luck
Ron
bit

Dick L · Mar 2, 2012

I know it is more drilling but if it is drilled off center you can fill the hole with a solid slug then center punch on center and redrill in the proper location.

JMS/.MN · Mar 2, 2012

Vertical mill with an end mill bit. Work needs to be clamped tight to the table to maintain original center. I"d take those straps to a machine shop or else make new straps.

KF · Mar 2, 2012

I have no idea what this strap looks like or where it is located, but on non-critical parts in the past I have just welded the hole up, ground it down flat and drilled the hole out again. Of course, this depends on access to the hole on both sides of the strap.

Rick Kr · Mar 2, 2012

Are these holes currently bushed and worn out, and how critical is the dimension? Center to Center.

Mill would be the way to go, if you have one, or access to one. But if this is not a precision job, you could partially fill in the holes with weld, and grind them back to size with a die grinder. Little bit of a primitive fix, but it may be a easier if you don't own a drill press or mill.

Still you have 120 holes to repair. And a 1/2 inch drill in your hand isn't gonna do it for your wrists and forearms.

You didn't mention what tools you have available. You could also fill the holes completely with weld and then burn new holes if you have access to a burn table.

Rick

wisbaker · Mar 2, 2012

With a mill or drill press you could rig something up to work with an end mill or holesaw. Another idea might be to get a brass rod the diameter of the hole you WANT, stick it in the hole you have and weld up the oblong side alongside the brass. My build-up shop did stuff like that on our raw material grinders and pulverizers when the pilot holes got wallowed out.

ss55 · Mar 2, 2012

You need an end mill if you want to relocate the hole centers back into their original locations. A drill bit will pull off location into the center of the elongated hole. For 120 holes I'd take them to a blacksmith or machine shop.

Have you priced new straps? If your planter is a popular model the manufacturer or a third party probably sell rebuild kits. If the straps are simple, new ones will cost less than machining and bushing the old ones.

Check the pivot shafts for wear too. If all the wear is on one side of the shaft you may be able to rotate the shafts 180 degrees to get a new wear surface.

Good luck.

buickanddeere · Mar 2, 2012

Only way to get a round true hole is with a mill.

J.ReinkeFarms · Mar 2, 2012

Stick a piece of copper or brass in the hole, hold it tight to the non wore side, weld solid, grind smooth, done.

GeneMO · Mar 2, 2012

Sounds like new straps might be cheaper and faster.

Gene

Dick L · Mar 2, 2012

Might not be the only way but it sure would be the fastest way.

I counter bores 300 holes today to .900 X .310 deep on my old round arm Bridgeport. Pretty good day for the old girl.

rad · Mar 2, 2012

I disagree with the 'one way only' statement. A good alternative is to use a punch - if available. I've used this techique many times on thinner materials say 0.125 or less. Another alternative is to drill the hole size you want in some material, clamp it tightly over the worn home and drill. The template will keep the bit from wandering all over the place.

Good luck!

Anonymous-0 · Mar 2, 2012

I agree a reamer is your friend

MarkB_MI · Mar 2, 2012

Chucking reamer?

paul · Mar 2, 2012

Thanks guys, kinda a 'winter projects' sort of deal that I better get after or leave another year.

Got a JD corn planter the linkages are getting a little worn, got some bushings here for it, could just get new simple straps for it too.

The bean planter is the one tho, 15 row old IHC machine, don't think they make frame parts, if they do would be so old as to be doubled in price so couldn't afford to replace. These are H brackets, a little harder to handle on the drill press.

And woke up the other morning, thinking, oh, can't just stick a drill bit into an egg shaped hole and expect good results, I better think this project out a little bit!

I'm not a good welder, guess that many holes would give me some practice!

Some of the bits shown here put in my drill press might give me a good chance at it. Was wondering if a reamer - as mentioned by a few - would give me a round hole to finish up.

Thanks.
--->Paul

JMS/.MN · Mar 2, 2012

Might be that not all holes are egg-shaped the same way, so a drill, reamer, etc. will give you a round hole but not necessarily centered like the original. You mentioned H brackets....what, two straps welded to a pipe spacer? Could easily start from scratch to make them. Drill the holes in new straps, build a jig to hold the 3 pcs together, and weld them. For the jig, I"d use two angle irons welded on a couple of spacer flat irons, with holes drilled to match the straps. Might use a small channel in the location of the spacer pipe, to hold it. Bolt the straps to the jig, add the spreader pipe, and weld in place. Should end up with 15 identical brackets.

oblong holes need to be round?

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