2014 POTD Thread Archive

My son is building a new engine for his Subaru, he purchased this block from somewhere. The current operation is replacing the stock head studs with high strength 1/2 inch studs, so he can run 30 PSI turbo boost. This Subaru is a money sink, he breaks it just about every time he takes it to the track, but it's his money.:nuts: OK, I used to do that too, I guess it runs in the family.

11 of the 12 stud holes went just fine, BUT, in one of them he ran into an unexpected Heli-Coil. I heard it squealing just before I heard the drill bit snap. OK, now we have about 2 1/2 inches of shattered 27/64 drill bit, wound up in a Heli-Coil down a 4 inch deep hole.:bawling:

The top couple inches of drill bit came out pretty easy with about 2 hours of probing around and twisting it around with some 1/8 welding rod stuffed down the flutes and a pair of vice grips.

Of course the rest of the drill bit is wedged into the aluminum in the bottom of the hole so it's not moving and there is no way to break it up because it's captured so tightly.

The problem: How to get the rest of this mess out and save the $1000 engine block that is currently not available from anywhere.

Here is what I did:

The engine block
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Most of the broken pieces and another drill bit for reference
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The tools
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The first order of business was to drill a hole through the drill bit to get enough clearance to be able to break it up and get it un-wedged from the block. So up into he milling machine it goes. Start slow so the burr doesn't walk off to the side and bugger up the hole. Once the center is established, then you can pour the coal to it.

What is left of the 6 inch long carbide burr that I ordered for this project, the burr and the shank are fine, just not together anymore. I got it hot enough while drilling that the brazed joint failed, I guess I poured on a little too much coal. Fortunately, I had most of the drilling work done at that point so I was able to continue on with out it.
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That was really an Oh S^%& moment:panic:, luckily, the burr was free in the hole and just fell out when I turned the block upside down. I'm going to attempt to put it back together, that will be for another day. If that doesn't work, I have a nice hard piece of 1/4 inch drill rod to use for something else.

Heli-Coil cutting tool, made from a 3/8 wood drilling spade bit, normally I would grind up a broken tap for this purpose, but in this case I had to reach down the hole about 3 1/2 inches. I would normally unscrew a Heli-Coil, but in this case it wasn't possible because there wasn't enough left to grab on to.
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The round punch with a chisel end ground to act as a wedge to break up the drill bit, I keep a few junk HF punches around for using like this.
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1/16 SS welding rod bent into a hook to grab stuck pieces of Heli-Coil that would not come out with the magnet.
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After about another 3 hours of drilling, probing, careful punching, twisting, and looking down the hole with a HF inspection camera, I managed to get all of the pieces out. Now it's ready to accept the new Heli-Coil.:biggrin:

Too bad I can't charge him for my time.:whistle: That's OK, now he owes me one, again. Hmmm, my roof needs to be de-mossed......

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Mom is still farming since Dad died and has a center pivot irragation system. It is somewhat older and the electric motors supposedly cant be rebuilt anymore so new ones have to be used. These motors are what drive the wheels. The current company charged her $160 for 2 plates to adapt the new motors to the old towers. I had her send me one and I am making her several out of pieces of angle that I had laying around. Thickness doesnt matter. Hopefully will save her some $$ in the future. The ones they built her are crap and not straight and the holes dont line up. It even was custom ground on one side to fit the drive assembly as it was made too wide.
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My son is building a new engine for his Subaru, he purchased this block from somewhere. The current operation is replacing the stock head studs with high strength 1/2 inch studs, so he can run 30 PSI turbo boost. This Subaru is a money sink, he breaks it just about every time he takes it to the track, but it's his money.:nuts: OK, I used to do that too, I guess it runs in the family.

11 of the 12 stud holes went just fine, BUT, in one of them he ran into an unexpected Heli-Coil. I heard it squealing just before I heard the drill bit snap. OK, now we have about 2 1/2 inches of shattered 27/64 drill bit, wound up in a Heli-Coil down a 4 inch deep hole.:bawling:

The top couple inches of drill bit came out pretty easy with about 2 hours of probing around and twisting it around with some 1/8 welding rod stuffed down the flutes and a pair of vice grips.

Of course the rest of the drill bit is wedged into the aluminum in the bottom of the hole so it's not moving and there is no way to break it up because it's captured so tightly.

The problem: How to get the rest of this mess out and save the $1000 engine block that is currently not available from anywhere.

Here is what I did:

The engine block


Most of the broken pieces and another drill bit for reference



The tools


The first order of business was to drill a hole through the drill bit to get enough clearance to be able to break it up and get it un-wedged from the block. So up into he milling machine it goes. Start slow so the burr doesn't walk off to the side and bugger up the hole. Once the center is established, then you can pour the coal to it.

What is left of the 6 inch long carbide burr that I ordered for this project, the burr and the shank are fine, just not together anymore. I got it hot enough while drilling that the brazed joint failed, I guess I poured on a little too much coal. Fortunately, I had most of the drilling work done at that point so I was able to continue on with out it.

That was really an Oh S^%& moment:panic:, luckily, the burr was free in the hole and just fell out when I turned the block upside down. I'm going to attempt to put it back together, that will be for another day. If that doesn't work, I have a nice hard piece of 1/4 inch drill rod to use for something else.

Heli-Coil cutting tool, made from a 3/8 wood drilling spade bit, normally I would grind up a broken tap for this purpose, but in this case I had to reach down the hole about 3 1/2 inches. I would normally unscrew a Heli-Coil, but in this case it wasn't possible because there wasn't enough left to grab on to.


The round punch with a chisel end ground to act as a wedge to break up the drill bit, I keep a few junk HF punches around for using like this.


1/16 SS welding rod bent into a hook to grab stuck pieces of Heli-Coil that would not come out with the magnet.


After about another 3 hours of drilling, probing, careful punching, twisting, and looking down the hole with a HF inspection camera, I managed to get all of the pieces out. Now it's ready to accept the new Heli-Coil.:biggrin:

Too bad I can't charge him for my time.:whistle: That's OK, now he owes me one, again. Hmmm, my roof needs to be de-mossed......

I hate jobs that go to crap like that. I feel your pain on this one.
 
I didn't get any machining done in the shop last night. I was helping my son diagnose/troubleshoot his new truck. Oh well, still time well spent with my son. He just started a new job so I will have less time with him now between work and finishing up his degree over the next several months.:bawling:
 
I have to drive forty-eight, 4mm-0.7 threaded, slotted inserts into 1/4" holes in 1/2" MDF. I really like the inserts with Allen drives, but they weren't available in this small metric size.To set these reasonably straight you need a large screwdriver and a lot of downward force. I need them slightly below the surface. So the large screwdriver is a pain to push and chews up the edges of the hole. I have a box of miscellaneous, old screwdrivers. I decided to grind the end of one to fit the insert slot and a pilot point to hold it straight. It has a hex shaft, so after I ground it I decided to just cut the shaft off the handle and use it in my super slow, super torquey Makita drill.

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Ken

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Todays project isnt as involved as some others .. but i had a few extra minutes .

Started making a new compound clamp for my g0602 .
Ill get some holes drill and tapped tomarow .. total time invested will be under 90 minutes if everything goes as planned
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This isn't going on anything for NASA but a Shovelhead I'm finishing up a 'frame off' on. The owner wanted to sprinkle in a few brass bits in memory of his brother. I sourced the kicker pedal he wanted and found a brass oil bag plug as well. The tranny fill plug was just butt ugly so :brightidea:.

I knew I had one little piece of brass round stock.

So I started with this:

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And found this hiding in there (These things have a tendency to seep around this plug so I cut an 0-Ring receiver groove):

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Here's the 35yo OEM piece being replaced:

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And here it is at home:

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I got to use my brandy new Aloris knurling tool that was given to me a while back. It sure beats the scissor type that came with my import tool holders to heck and back.

Thanks for looking.

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Assembled one of the short wall sections in the shop today. Thought it might help to have the overhead crane for the first one, looks like they're going to go together and square up pretty easily.

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Found a fairly nice 3/8" drill chuck with a beat-up integral shaft in my inherited junk and made it usable on my mill.

The shaft was about 4" long and .530" diameter. I put a chunk of 1/2" shaft in the spindle chuck on the Logan and turned an inch or so of it down to .375". I then clamped the chuck on it and checked the runout on the shaft: about .015 out 3". Center drilled the end of the shaft, stuck a center in it and then turned the shaft down to .500". Cut it off, polished it until it fit a 1/2" collet and stuck it in the mill. After a bit of fairly gentle adjusting with a rubber mallet it shows .001" TIR on a precision pin close to the jaws.

Tomorrow I'll stick something long and straight in it and see how much it wobbles out a few inches.
 
Have the timber frame on my shed assembled, now for a roof.

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Greg

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