need advice from you machinists

Fritz Maurer · Mar 5, 2013

I would like to drill a 1/4" hole down through these bolts to the bottom of the bolt hole, so can get some penetrant down by the threads. As you know, the first hole must be perfect, in case the bolt eventually has to be completely drilled out. My problem is the bolts twisted off crooked, and I fear the drill won't drill where I aim it. I thought about squaring the top off with an end mill, but that will leave a point in the center, and I'm not sure that's what I want to do. Ideas? Thanks, Fritz

JMS/.MN · Mar 5, 2013

The one on the right has plenty to weld a nut to. The left I"d try as well. Apply candle wax as it cools. Heat of welding helps to loosen, and the wax flows between the threads to loosen them. Sometimes I heat a couple times with the torch, wax again.....has never failed. Might try leaving it to soak in for a few hours. I use the mig welder, easier to control things than with a stick.

george md · Mar 5, 2013

Fritz,

Use a center cut end mill (2 or 4 flute)
as close to tap drill size as possible,many
times it will bring the remains out looking
like a helicoil. If it doesn't use a small
gouge to remove the rest.

george

flying belgian · Mar 5, 2013

What jms said.

gtractorfan · Mar 5, 2013

Might add, if you end up drilling into the bolts using left handed drills can help them back out. Even if you're slightly off center when you drill it out to the block's threads many times the piece will back out.

NCWayne · Mar 5, 2013

Like another reply suggests, the one on the right is protruding enough to weld to. That being the case, no more than it is sticking out, it would be easier to weld a washer to it first, and then a nut to the washer. Apply a penetrant of some type to it as it cools and once completely cool it will usually back out.

For the one broken off below the surface, what I do to find center is to use a transfer type center punch where the shank is the same size as the bolt hole. Even on a shallow hole it's not that hard to get one the right size close enough to center to work. If you don't have one of those punches, a standard center punch and a good eye will work just as good. The main thing is start with something like a 1/8 bit to insure it stays in the punch mark, and then increase in size from there.

Personally if the piece doesn't come out with a hole and a easy out, I'll use a small carbide burr to eat away the material of the piece until I can see the tops of the threads. Once I see the threads I'll use a punch I ground special to pick the remainder out. Hope yours doesn't get to this point because it's a royal PITA to do this way. Good luck.

moresmoke · Mar 5, 2013

What JMS said. If they are 3/8 studs, weld a 5/16 flat washer to the stud, than about a 7/16 nut on top of that. Will turn right out. If you can use a MIG that one on the left, the weld won't stick to the cast even if you touch it a little bit. It would take me longer to uncoil the leads on the welder than it would to take the studs out.

Don-Wi · Mar 5, 2013

Yup, weld a nut to them. The one on the left, dab a little weld on it first to built it up some, then weld a washer to it and then a nut to the washer. Works everytime.

If it doesn't come out on the 1st try, just do it again. Main thing that helps for me is to get on it with a wrench as soon as you can after setting down the mig gun.

Donovan from Wisconsin

Fritz Maurer · Mar 5, 2013

I have used the welded nut trick many times, but that's not going to work here. There is about 2-1/2" of bolt stuck in those holes. Problem is, this is a dangerous head to heat, especially in one area. This has to be an excavation job.

Anonymous-0 · Mar 5, 2013

I would mig weld a washer to the broken stud, even the below surface one. And then weld a square nut to the washer. The electricity moves from the cast to the stud through the rust. That in itself, helps loosen up the broken stud. Lots of slow easy working the nut back and forth and plenty of penetrating oil.

Handyman · Mar 5, 2013

take a piece of 3/8 steel and drill a hole the same size as the ones in the head and clamp that to the head over the broken bolts, then use that as a guide to start a hole in the bolts so you have a center point in the broken bolts.

Don-Wi · Mar 5, 2013

If it's possible to set it up on a mill, that'd be the best way then if you can't weld on it. Either spot face it with an endmill then drill it, or cut the whole thing out with an endmill.

Donovan from Wisconsin

Janicholson · Mar 5, 2013

As below on welding on a washer/nut combo.
If using an easy out like thing do not use a spiral type. Use the straight shank style, they do not self tighten and wedge things worse than before. Sears has them Last I looked. Jim

RWT · Mar 5, 2013

Where I don't have a center cutting end mill I drill a hole in the bolt and then a non center cutting mill will work.

In this method the hole doesn't have to dead on in the middle.

Alternatively, if you try to drill it and the bit walks off center you can use the end mill to clean it up.

It's worked for me.

RT (my 2 cents)

Jim in MN · Mar 5, 2013

Is there enough hole to pick up center on the left hole? Or enough diameter to find center on the right hole? If not you could probably get pretty close by finding hole centers on the port to the left and then moving over the port centerline distance.

Once you find center use a #4 or #5 center drill to start the hole. Nice steady pressure until the tip is engaged. Then you can drill thru the center with whatever dia you want.

MarkB_MI · Mar 6, 2013

Fritz, you're wasting your time with penetrating oil. It doesn't. (Doesn't penetrate, that is.)

Anonymous-0 · Mar 6, 2013

I would make a jig plate, by drilling the holes, at the right distance apart (test by using the other ports, where the bolts did come out). I would use the port to the left of the one in question, drill the holes to fit it, then do the same operation, just the right distance away. Alternatively, bolt 2 bushings in the open port, weld a cross bar, leaving enough room on the cross bar, to weld 2 more bushings, so you can bolt to the good port, and drill out the broken bolts. Use the wax trick on the broken bolts, and grind off the one that is standing proud of the block. Pictorially, the bushing jig would look like this: O___O___O___O

Anonymous-0 · Mar 6, 2013

One other thing, is that an international TD340 head, sure looks like those are injector bolts!

LorenMN · Mar 6, 2013

Since you already have the head sitting on the Bridgeport table, no sense to even consider welding. Get a good setup first, with the head clamped down at the correct angle and parallel to the table. I think I would then start off as someone else suggested and indicate the center of the port to the left, then find the distance to the center of the threaded holes for that port. Then move over and find center of the end port, and move out the thread centers. I would first spot face the bolts with a 2 flute endmill a little smaller than the minor dia. of the thread, so you can drill into a flat surface. Then center drill, then follow that with an 1/8" drill, then drill with a bit 1/32" smaller than tap drill size, then tap drill size if it still hasn't started to turn.

Blackhole49 · Mar 6, 2013

Get it as close to center on your mill as you can and start with a small left hand twist bit. Then keep increasing the size slowly. Chances are the bolts will un-thread themselves. If not, go until you can just start to see the threads in the hole, then pry out with small punch.

unclemerle · Mar 6, 2013

JRSutton · Mar 6, 2013

what I tried last time was a small rounded grinding stone. not sure what to even call it.

I put that in my end mill and sort of dished the broken bolt out a little.

that made it much easier for me to center a small drill bit.

Yes you want to be as dead on centered as you can, but in reality being a little off wont matter all that much.

More important is you want to be straight and parallel with the centerline of the bolt.

once you get enough hogged out - it's going to come out whether you're in the middle or not.

teddy52food · Mar 6, 2013

I would never even try an easy out. They only work if it comes out easy which it won't if it is twisted off already.

teddy52food · Mar 6, 2013

Forget about using an easy out on those.

need advice from you machinists

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