How best to remove broken & rusted bolt in block

[dtfeld]

I guess I should check these this year! I need to do belts

Hopefully, you don't have any broken bolts. The hardest part other than that was getting the guards off. I' leaving them off and going to modify to make it easier to access.

 

[Scott215]

How come nobody mentioned a welding a nut onto the stud and backing it out

 

[KrazyKarl]

Spent all day alternating between heat and penetrant oil, then working with a chisel. No joy.

Tomorrow I’m going to grind the face flat and attempt to drill it out. I like the idea of a carbide bit as another option.

You don't want to start off with a carbide bit because if you break it your stuck. You need a high speed to start with then if it breaks the cobalt or carbide will cut through it. If it's around 1/2" I would start with a 3/8" then keep stepping up to the next size until you start seeing the insides of the threads. Then just peel the threads out & run a tap through it.

 

[Steve S]

You don't want to start off with a carbide bit because if you break it your stuck. You need a high speed to start with then if it breaks the cobalt or carbide will cut through it. If it's around 1/2" I would start with a 3/8" then keep stepping up to the next size until you start seeing the insides of the threads. Then just peel the threads out & run a tap through it.

A cobalt tool has the same Rockwell harness as the HSS tool. The difference is the cobalt tool has a higher “red hardness”. What is “red hardness”? That means the tool will maintain the cutting edge longer at elevated temperatures during the cut. But like carbide but to a much lesser degree, cobalt is more brittle then a plain HSS tool.

 

[ttmott]

Most of my mill cutters are solid carbide because they hold a sharp edge cutting difficult materials like stainless and cast iron. I have some carbide drill bits but they are only used in the mill with controlled feed rates. Again for difficult materials. Carbide in a hand held drill isn't a good idea due to the intolerance to lateral deflection and chattering; they will chip and break easier due to their low ductility. I have an index of M35 cobalt and another of HSS drills. The M35 Cobalt simply cut and cut easily through most materials while doing a good job keeping sharp. The key is the drill point configuration (angle and if the point is split and/or relieved). For metals I keep to 135 degree split point and relieved on drill bits for metals. My HSS drill set is relegated to wood, fiberglass, and metals I'm not too concerned about like galvanized pipe and sheetmetal etc.
You can always tell a solid carbide tool as it is significantly heavier than anything else.

The key is keeping the drills sharp. Get a good drill sharpener like a Drill Doctor. I have a Darex machine that I use for both drills and mill tooling.

With all that said if you need to get into drilling larger holes then consider carbide tipped or indexable tooling - the best of both worlds.

 

[ttmott]

Most of my mill cutters are solid carbide because they hold a sharp edge cutting difficult materials like stainless and cast iron. I have some carbide drill bits but they are only used in the mill with controlled feed rates. Again for difficult materials. Carbide in a hand held drill isn't a good idea due to the intolerance to lateral deflection and chattering; they will chip and break easier due to their low ductility. I have an index of M35 cobalt and another of HSS drills. The M35 Cobalt simply cut and cut easily through most materials while doing a good job keeping sharp. The key is the drill point configuration (angle and if the point is split and/or relieved). For metals I keep to 135 degree split point and relieved on drill bits for metals. My HSS drill set is relegated to wood, fiberglass, and metals I'm not too concerned about like galvanized pipe and sheetmetal etc.
You can always tell a solid carbide tool as it is significantly heavier than anything else.

The key is keeping the drills sharp. Get a good drill sharpener like a Drill Doctor. I have a Darex machine that I use for both drills and mill tooling.

With all that said if you need to get into drilling larger holes then consider carbide tipped or indexable tooling - the best of both worlds.

Here - I laid out a couple of tools to illustrate differences and that looks don't always reveal material.
top to bottom -
The first two are HSS 118 degree screw machine drill bits; don't look the same but they are.
The third next to the green tube is solid carbide Jobber drill bit with a 135 degree tip.
The gold colored drill bit is the M35 Cobalt HSS drill with a 135 degree tip
The next by the clear tube is a solid carbide two flute end mill.
Next is a roughing end mill that is HSS but Ti coated to get extended length in sharpness. Drill bits that are Ti coated are, in my opinion, not any better than standard HSS uncoated so not worth any more to pay for.
And last is an indexable tool where the tool is HSS but the removable inserts are Carbide.

 

[Maybe A Dancer]

Always appreciate your sharing of the wide knowledge bank you possess.

BEST !

RWS

 

[Steve S]

Here - I laid out a couple of tools to illustrate differences and that looks don't always reveal material.
top to bottom -
The first two are HSS 118 degree screw machine drill bits; don't look the same but they are.
The third next to the green tube is solid carbide Jobber drill bit with a 135 degree tip.
The gold colored drill bit is the M35 Cobalt HSS drill with a 135 degree tip
The next by the clear tube is a solid carbide two flute end mill.
Next is a roughing end mill that is HSS but Ti coated to get extended length in sharpness. Drill bits that are Ti coated are, in my opinion, not any better than standard HSS uncoated so not worth any more to pay for.
And last is an indexable tool where the tool is HSS but the removable inserts are Carbide.

View attachment 161009

Nice assortment of tools and explanations.
Coatings help for two reasons. They add lubricity allowing the chips to clear the workpiece. This helps in drilling and tapping. And they are harder than the steel the tool are made of. However, to see the additional benefits they need to be run properly. The average TiN coated tool should be run 25% faster than an uncoated tool. Advanced coatings such as TiCN (Titanium Carbo Nitride) or TiAlN (Titanium Aluminum Nitride) should be run 50%-75% faster than an uncoated tool. These tools and coatings are designed to be run in a shop environment on CNC machines for production, not on a Bridgeport type machine for one or two piece runs. Coatings allow tools to be more wear resistant and to run faster, producing more parts. That’s how they justify the additional cost.
Finally, like steels there are different grades of carbide. There are grades with high wear resistance designed for abrasive materials such as cast iron, high silicon aluminum and even titanium. Other grades are harder used for stainless steels and heat resistant alloys such as Inconel. One option that hasn’t been mentioned is a “powdered metal” tool. PM tools have a uniform grain structure similar to carbide but are less brittle and more forgiving like a steel tool. The uniform grain structure adds wear resistance and provides tool life.
These higher performance tools will be found at an industrial distributor not places like Home Depot or Ace Hardware.

 

[Steve S]

Here - I laid out a couple of tools to illustrate differences and that looks don't always reveal material.
top to bottom -
The first two are HSS 118 degree screw machine drill bits; don't look the same but they are.
The third next to the green tube is solid carbide Jobber drill bit with a 135 degree tip.
The gold colored drill bit is the M35 Cobalt HSS drill with a 135 degree tip
The next by the clear tube is a solid carbide two flute end mill.
Next is a roughing end mill that is HSS but Ti coated to get extended length in sharpness. Drill bits that are Ti coated are, in my opinion, not any better than standard HSS uncoated so not worth any more to pay for.
And last is an indexable tool where the tool is HSS but the removable inserts are Carbide.

View attachment 161009

A 118 degree drill is a "General Purpose" drill. It is good for soft materials but is prone to "walking". A 135 degree split point drill is designed for harder materials and can be "self centering". A carbide drill unless a GP jobber drill is probably a 140 degree point.
TiN (Titanium Nitride) is an old coating that came out in the 80's. It looks good on Home Depot's display. TiCN, TiALN and other multilayered coating provide much greater benefits to the machine shop.
That roughing tool looks like a "fine pitch" rougher not a coarse pitch heavy duty tool.
The bronze colored drill is simply a treatment for looks so it can be identified as something other than a HSS tool. It provides no benefit in performance. The original material is normal shiny steel.

 

[blaster]

How come nobody mentioned a welding a nut onto the stud and backing it out

I recall a brief mention of welding on a nut but that never had any more discussion. The problem with welding on a nut (despite the heat) is that the weld must be strong enough to hold. I tried welding nuts with an exhaust manifold on a 5.4 2v Ford to extract broken off studs. I got two out of four I tried. My actual mechanic friend extracted the other studs out after my butchery and I was humbled. This stuff ain't easy.

 

[Blueone]

A 118 degree drill is a "General Purpose" drill. It is good for soft materials but is prone to "walking". A 135 degree split point drill is designed for harder materials and can be "self centering". A carbide drill unless a GP jobber drill is probably a 140 degree point.
TiN (Titanium Nitride) is an old coating that came out in the 80's. It looks good on Home Depot's display. TiCN, TiALN and other multilayered coating provide much greater benefits to the machine shop.
That roughing tool looks like a "fine pitch" rougher not a coarse pitch heavy duty tool.
The bronze colored drill is simply a treatment for looks so it can be identified as something other than a HSS tool. It provides no benefit in performance. The original material is normal shiny steel.

Now you guys are all of a sudden very interesting…..

 

[dtfeld]

How come nobody mentioned a welding a nut onto the stud and backing it out

I actually bought a welder for this project, but a dock neighbor who's a welder by trade, cautioned me to not use the welder on the assembled engine as there are too many electrical/electronics on the engine and they may not survive the welding amps/voltage. All the videos I saw and viewed were of a disassembled heads or other component, so I elected to forgo the welder.

In the end, successfully removing the bolt was a combination of the right tool/bit, physical strength, and most importantly patience! Patience was the most critical factor. Removing this stuck bolt was VERY time consuming, but f*ing it up would be worse! And you couldn't find a worse location...very tight, bad angles etc.

It was probably the hardest job I've done on any boat I've owned.

 

[dtfeld]

These bolts for you CAT owners (I'll bet Cummin is the same) are hardened 10.9 bolts, so tough stuff.

My recommended steps after all this is basically the same. If you can isolate the part your trying to remove the bolt/stud from, I think welding a nut/washer on is a good idea. On a whole assembled engine...maybe not.

I spent a lot of time early on, trying to get the punch in the center. I missed several times and ground a new flat surface and tried again. I used my cell phone camera to guesstimate how well I was doing. It ended up being a useful tool, and getting me very close to dead center.

Once I had a good center punch I use a small M42 Coltalt 60* centering drill to get a small/shallow guide hole started. From there, the @ttmott Hansen recommended drills cut through these bolts very nicely. I did not have room to get anything but a hand drill in and had to drill thru a M8 30mm bolt. It took several hours, and (several breaks), but these drill bits cut nice spirals, and chips depending on how much force I was able to apply.

 

[DennChar]

I have found that a small amount of grease applied before final assembly will save alot of this kind of frustration. This works on both cars and boats that are exposed to wet and salty conditions.

 

[blaster]

I have found that a small amount of grease applied before final assembly will save alot of this kind of frustration. This works on both cars and boats that are exposed to wet and salty conditions.

The grease ruins the torque required. Even anti seize can cause over tightening. Best to do it dry like lug nuts. Figure out seizing when you tear it down.

 

[dtfeld]

The grease ruins the torque required. Even anti seize can cause over tightening. Best to do it dry like lug nuts. Figure out seizing when you tear it down.

I went back with some anti seize. I realize this does change the torque spec and retention , but these are working bolts that are going to be loosened/tightened on a regular basis. I'd prefer not to drill these out ever again. I think I'll just replace the bolds when I do the belts.