removing old exhaust manifold studs/bolts rusted in place

[Grumpy]

the link's below will be useful

(1) spray with a good penetrating oil,

(2) heat briefly with propane torch, or acetylene torch

if you have a spark plug or a bolt thats rusted or jammed in its threads , heat it with a propane torch and cool it with either a 50% /50% mix of acetone and marvel mystery oil , several times in succession to expand with heat and contract the threads with cooling and penetrating oil spray, and follow that with use the cooling and penetrating spray below.
don,t force the threads it will only strip out

just a tip, heating a stuck bolt with a torch, and cooling it with a liberal soak down , in penetrating oil several times, in succession then soaking it down and letting it sit over night has frequently made the job of loosening stuck threads many times.

(3) spray with OR A GOOD PENETRATING OIL like pb blaster / liquid wrench, freealloil etc. and tap frequently and lightly with a hammer on the broken stud or bolt to allow vibration to let the penetrating oil seep into the threads if it can,
http://www.freealloil.com/



(3) spray with

http://www.freealloil.com/

you might want to try this I found it works even better than most common penetrating oil sprays
http://www.freealloil.com/ OR A GOOD PENETRATING OIL like pb blaster / liquid wrench,\l etc.

(4) wait 5 minutes MINIMUM and RE-SPRAY with
http://www.freealloil.com/ OR A GOOD PENETRATING OIL like pb blaster / liquid wrench, etc.


(5)spray for a minimum of 15-16 seconds with
http://www.loctitefreezeandrelease.com/
yes that does mean the cans only good for a couple jammed threads

Q: What causes an exhaust manifold stud/bolt to break?

A: The exhaust manifolds are formed from the factory using fine grain cast iron, and like most metals, it expands and contracts during duty cycles of heating and cooling. This expansion happens naturally, and at first, the manifold and mounting studs are in a state of “elastic deformation.” Elastic deformation is basically expansion and contraction over a period of time retaining the original size and shape. Each duty cycle will provide tension stress on the studs or bolts that hold the manifold in place. The mounting hardware exhibits flexibility over time. However, as the manifold continues to expand and contract more dimensionally, each consecutive time creates larger and larger tension forces that move beyond the elastic state of deformation and become what is referred to as “plastic deformation.” Basically the manifold stretches beyond return and fractures the mounting stud, leaving the manifold permanently deformed and dimensionally changed. This expansion and stretching of the manifold bolts over numerous duty cycles eventually causes too much tension on the bolt(s), stretching them beyond capacity and causing them to fail.
I would strongly suggest BOTH stainless bolts studs and the use of ANTI SEIZE on the threads

Information provided by: ProMaxx Tools
THIS RELATED THREAD WILL BE HELPFUL IN THE REMOVAL OF OLD STUDS/BOLTS

I don,t know why this is ignored by so many people,
before RE-INSTALLING, YOUR NEW SPARK PLUGS
COAT THE SPARK PLUG THREADS,
WITH ANTI-SEIZE PASTE,
as it tends to prevent future problems

http://garage.grumpysperformance.com/index.php?threads/why-use-anti-seize-paste.9424/#post-39167

be very sure you use anti-seize paste on exhaust manifold stud/bolt threads also or you'll regret not doing so later

I recently had a guy bring a 1989 corvette into the shop, 7 of the 8 spark plugs were,locked solidly in the aluminum heads,
and after he tried to remove and change them,
he found they were locked solidly in the heads ,to the point they were just spinning only with a long breaker bar, and the threads on the plugs were filled with stripped aluminum that used too be threads in the aluminum head castings,
or put a bit differently,there were no longer the spark plug threads,in the heads, as that aluminum was wrapped around the spark plugs that were removed taking the previously machined aluminum threads out of the heads in the process.
the heads were totally stripped, out and the plugs were not going to be removable. this REQUIRES taking the heads off,
and too a machine shop to be re-welded and re-machined in most cases.
this could very easily cost well in excess of $300 and its so easy to prevent.
yes there are over sized steel spark plug thread, replacement thread inserts that can be used in some cases
but even those are best installed correctly with the damaged heads off the engine and work done at a trusted machine shop.
yes there are thread chaser tools

but in many cases the heads are damaged to the point the only really good option is weld up the damage and re-cut new threads


http://garage.grumpysperformance.com/index.php?threads/removing-rusted-broken-bolts.807/#post-43181

http://garage.grumpysperformance.co...en-bolt-and-screw-plug-removal.729/#post-1263

http://garage.grumpysperformance.co...op-needs-a-decent-drill-press.970/#post-50726

 

[87vette81big]

Monel is A Premium Super Stainless type metal.
Typically used in Nuclear Power plants.
The Reactor Cooling pipes.
Also used in Blast Furnaces.
Does not Electron Ion Degrade like cheap steels do with high heat.
Mopar Bob has snuck gave me Monel metal before .
Very Kool Stuff.

 

[Grumpy]

well worth watching

 

[Maniacmechanic1]

Interesting Grumpy.
It looks like he created the rust with Muratic acid and hit the steel with water and it air dried.
Has the Yellow tint yet.
I would like to see Salt water corrosion break away test.
Stuff eats almost anything Road Salt.
400-500 ft/lbs break away torque intial.
3-4 minutes soak time.
Just like working in a job shop environment.
No longer have that stress working on School Buses.
But still deal with road salt rust.

He did not test Seafoam penetrant.
Works pretty good also.
I have used ATF acetone mix .
Works pretty good.
But it failed to unstuck my 1959 Pontiac 389.
Nothing worked.
Just Ticture of Iodine 2%.
Works amazing.
Broke free after sitting since 1983.

 

[Grumpy]

this stuff works better than almost anything else I,ve4 tried if you simply repeatedly heat the offending threads with a torch and cool the threads with a spray of the penetrating fluid, and cycling the heat followed by penetrating oil 4-5 times then soak it down and let it sit several hours or over night

at times you'll want to fabricate a "cup" around the problem fastener with modeling clay

https://www.amazon.com/Claytoon-Set...d=1466872286&sr=8-17&keywords=plastilina+clay

to allow a significant volume of the penetrating oil to set around the threads over night

http://www.freealloil.com/

 

[Maniacmechanic1]

this stuff works better than almost anything else I,ve4 tried if you simply repeatedly heat the offending threads with a torch and cool the threads with a spray of the penetrating fluid, and cycling the heat followed by penetrating oil 4-5 times then soak it down and let it sit several hours or over night

at times you'll want to fabricate a "cup" around the problem fastener with modeling clay

https://www.amazon.com/Claytoon-Set...d=1466872286&sr=8-17&keywords=plastilina+clay

to allow a significant volume of the penetrating oil to set around the threads over night

http://www.freealloil.com/

Never seen Grumpy.
Want to try it.

 

[Grumpy]

https://www.mcmaster.com/left-hand-drill-bits

Inch Size Left-Hand Drill Bits

Also known as reverse-flute bits, the flutes spiral in the opposite direction of other bits. They are for use in reverse tool operation—most commonly to remove broken screws. Jobbers'length are the most common bits and have the rigidity and length required for most applications.

A split point keeps the bit centered without a pilot hole.

Bits with 135° point angle produce smaller chips than 118° point to prevent clogging.


Size Size Decimal
Equivalent O'all
Lg. Max.
Drilling Dp. Shank
Dia. Point Style For Use On Each
135° Point Angle—Jobbers' Length
Black- and Gold-Oxide High-Speed Steel
1/16" 0.0625" 1 7/8" 0.75" 1/16" Split Steel, Iron 88055A41 $5.51
5/64" 0.0781" 2" 0.88" 5/64" Split Steel, Iron 88055A42 5.51
3/32" 0.0938" 2 1/4" 1.22" 3/32" Split Steel, Iron 88055A43 5.51
7/64" 0.1094" 2 5/8" 1.47" 7/64" Split Steel, Iron 88055A44 5.51
1/8" 0.1250" 2 3/4" 1.5" 1/8" Split Steel, Iron 88055A45 5.51
9/64" 0.1406" 2 7/8" 1.63" 9/64" Split Steel, Iron 88055A61 5.51
5/32" 0.1563" 3 1/8" 1.88" 5/32" Split Steel, Iron 88055A46 6.41
11/64" 0.1719" 3 1/4" 2.09" 11/64" Split Steel, Iron 88055A62 7.38
3/16" 0.1875" 3 1/2" 2.28" 3/16" Split Steel, Iron 88055A47 7.70
13/64" 0.2031" 3 5/8" 2.41" 13/64" Split Steel, Iron 88055A63 8.61
7/32" 0.2188" 3 3/4" 2.47" 7/32" Split Steel, Iron 88055A64 9.22
15/64" 0.2344" 3 7/8" 2.5" 15/64" Split Steel, Iron 88055A65 9.84
1/4" 0.2500" 4" 2.63" 1/4" Split Steel, Iron 88055A48 10.65
17/64" 0.2656" 4 1/8" 2.75" 17/64" Split Steel, Iron 88055A66 11.31
9/32" 0.2813" 4 1/4" 2.81" 9/32" Split Steel, Iron 88055A67 13.53
19/64" 0.2969" 4 3/8" 2.94" 19/64" Split Steel, Iron 88055A49 15.37
5/16" 0.3125" 4 1/2" 3.16" 5/16" Split Steel, Iron 88055A51 16.15
3/8" 0.3750" 5" 3.5" 3/8" Split Steel, Iron 88055A52 24.94
7/16" 0.4375" 5 1/2" 3.94" 7/16" Split Steel, Iron 88055A53 32.87
1/2" 0.5000" 6" 4.45" 1/2" Split Steel, Iron 88055A54 41.80
118° Point Angle—Jobbers' Length
Uncoated High-Speed Steel
1/32" 0.0313" 1 3/8" 0.43" 1/32" Standard Steel, Iron, Plastic 2876A11 6.62
3/64" 0.0469" 1 3/4" 0.65" 3/64" Standard Steel, Iron, Plastic 2876A12 4.57
1/16" 0.0625" 1 7/8" 0.75" 1/16" Standard Steel, Iron, Plastic 2876A13 4.38
5/64" 0.0781" 2" 0.84" 5/64" Standard Steel, Iron, Plastic 2876A14 4.44
3/32" 0.0938" 2 1/4" 1.06" 3/32" Standard Steel, Iron, Plastic 2876A15 4.56
7/64" 0.1094" 2 5/8" 1.28" 7/64" Standard Steel, Iron, Plastic 2876A16 4.72
1/8" 0.1250" 2 3/4" 1.37" 1/8" Standard Steel, Iron, Plastic 2876A17 4.72
9/64" 0.1406" 2 7/8" 1.46" 9/64" Standard Steel, Iron, Plastic 2876A18 4.92
5/32" 0.1563" 3 1/8" 1.68" 5/32" Standard Steel, Iron, Plastic 2876A19 5.49
11/64" 0.1719" 3 1/4" 1.78" 11/64" Standard Steel, Iron, Plastic 2876A21 6.35
3/16" 0.1875" 3 1/2" 1.93" 3/16" Standard Steel, Iron, Plastic 2876A22 6.81
13/64" 0.2031" 3 5/8" 2.03" 13/64" Standard Steel, Iron, Plastic 2876A23 7.09
7/32" 0.2188" 3 3/4" 2.06" 7/32" Standard Steel, Iron, Plastic 2876A24 6.80
15/64" 0.2344" 3 7/8" 2.15" 15/64" Standard Steel, Iron, Plastic 2876A25 9.79
1/4" 0.2500" 4" 2.25" 1/4" Standard Steel, Iron, Plastic 2876A26 9.41
17/64" 0.2656" 4 1/8" 2.34" 17/64" Standard Steel, Iron, Plastic 2876A27 10.35
9/32" 0.2813" 4 1/4" 2.37" 9/32" Standard Steel, Iron, Plastic 2876A28 10.33
19/64" 0.2969" 4 3/8" 2.46" 19/64" Standard Steel, Iron, Plastic 2876A29 11.72
5/16" 0.3125" 4 1/2" 2.56" 5/16" Standard Steel, Iron, Plastic 2876A31 11.96
21/64" 0.3281" 4 5/8" 2.65" 21/64" Standard Steel, Iron, Plastic 2876A32 13.41
11/32" 0.3438" 4 3/4" 2.74" 11/32" Standard Steel, Iron, Plastic 2876A33 14.79
23/64" 0.3594" 4 7/8" 2.78" 23/64" Standard Steel, Iron, Plastic 2876A34 17.86
3/8" 0.3750" 5" 2.87" 3/8" Standard Steel, Iron, Plastic 2876A35 18.10
25/64" 0.3906" 5 1/8" 2.96" 25/64" Standard Steel, Iron, Plastic 2876A36 20.52
13/32" 0.4063" 5 1/4" 3.06" 13/32" Standard Steel, Iron, Plastic 2876A37 20.57
27/64" 0.4219" 5 3/8" 3.09" 27/64" Standard Steel, Iron, Plastic 2876A38 23.99
7/16" 0.4375" 5 1/2" 3.18" 7/16" Standard Steel, Iron, Plastic 2876A39 24.22
29/64" 0.4531" 5 5/8" 3.28" 29/64" Standard Steel, Iron, Plastic 2876A41 28.67
15/32" 0.4688" 5 3/4" 3.37" 15/32" Standard Steel, Iron, Plastic 2876A42 29.34
31/64" 0.4844" 5 7/8" 3.4" 31/64" Standard Steel, Iron, Plastic 2876A43 32.21
1/2" 0.5000" 6" 3.5" 1/2" Standard Steel, Iron, Plastic 2876A44 31.02
Wire Gauge Size Left-Hand Drill Bits

Also known as reverse-flute bits, the flutes spiral in the opposite direction of other bits. They are for use in reverse tool operation—most commonly to remove broken screws. Jobbers' length are the most common bits and have the rigidity and length required for most applications.



Each

Size Size Decimal
Equivalent O'all
Lg. Max.
Drilling Dp. Shank
Dia. Point Style For Use On 1-11 12-Up
118° Point Angle—Jobbers' Length
Uncoated High-Speed Steel
60 0.0400" 1 5/8" 0.6" 0.04" Standard Steel, Iron, Plastic 3024A286 $5.14 $4.36
59 0.0410" 1 5/8" 0.6" 0.041" Standard Steel, Iron, Plastic 3024A285 5.14 4.36
58 0.0420" 1 5/8" 0.6" 0.042" Standard Steel, Iron, Plastic 3024A284 5.14 4.36
57 0.0430" 1 3/4" 0.66" 0.043" Standard Steel, Iron, Plastic 3024A283 5.14 4.36
56 0.0465" 1 3/4" 0.65" 0.0465" Standard Steel, Iron, Plastic 3024A282 5.14 4.36
55 0.0520" 1 7/8" 0.77" 0.052" Standard Steel, Iron, Plastic 3024A281 5.14 4.36
54 0.0550" 1 7/8" 0.76" 0.055" Standard Steel, Iron, Plastic 3024A279 5.14 4.36
53 0.0595" 1 7/8" 0.75" 0.0595" Standard Steel, Iron, Plastic 3024A278 5.14 4.36
52 0.0635" 1 7/8" 0.74" 0.0635" Standard Steel, Iron, Plastic 3024A277 5.14 4.36
51 0.0670" 2" 0.86" 0.067" Standard Steel, Iron, Plastic 3024A276 5.14 4.36
50 0.0700" 2" 0.86" 0.07" Standard Steel, Iron, Plastic 3024A275 5.07 4.30
49 0.0730" 2" 0.85" 0.073" Standard Steel, Iron, Plastic 3024A274 5.07 4.30
48 0.0760" 2" 0.84" 0.076" Standard Steel, Iron, Plastic 3024A273 5.07 4.30
47 0.0785" 2" 0.84" 0.0785" Standard Steel, Iron, Plastic 3024A272 5.07 4.30
46 0.0810" 2 1/8" 0.96" 0.081" Standard Steel, Iron, Plastic 3024A271 5.07 4.30
45 0.0820" 2 1/8" 0.96" 0.082" Standard Steel, Iron, Plastic 3024A269 5.07 4.30
44 0.0860" 2 1/8" 0.95" 0.086" Standard Steel, Iron, Plastic 3024A268 5.07 4.30
43 0.0890" 2 1/4" 1.07" 0.089" Standard Steel, Iron, Plastic 3024A267 5.07 4.30
42 0.0935" 2 1/4" 1.06" 0.0935" Standard Steel, Iron, Plastic 3024A266 5.07 4.30
41 0.0960" 2 3/8" 1.18" 0.096" Standard Steel, Iron, Plastic 3024A265 5.07 4.30
40 0.0980" 2 3/8" 1.17" 0.098" Standard Steel, Iron, Plastic 3024A264 5.07 4.30
39 0.0995" 2 3/8" 1.17" 0.0995" Standard Steel, Iron, Plastic 3024A263 5.07 4.30
38 0.1015" 2 1/2" 1.23" 0.1015" Standard Steel, Iron, Plastic 3024A262 5.07 4.30
37 0.1040" 2 1/2" 1.22" 0.104" Standard Steel, Iron, Plastic 3024A261 5.07 4.30
36 0.1065" 2 1/2" 1.22" 0.1065" Standard Steel, Iron, Plastic 3024A259 5.07 4.30
35 0.1100" 2 5/8" 1.28" 0.11" Standard Steel, Iron, Plastic 3024A258 5.07 4.30
34 0.1110" 2 5/8" 1.27" 0.111" Standard Steel, Iron, Plastic 3024A257 5.07 4.30
33 0.1130" 2 5/8" 1.27" 0.113" Standard Steel, Iron, Plastic 3024A256 5.07 4.30
32 0.1160" 2 3/4" 1.39" 0.116" Standard Steel, Iron, Plastic 3024A255 5.07 4.30
31 0.1200" 2 3/4" 1.38" 0.12" Standard Steel, Iron, Plastic 3024A254 5.07 4.30
30 0.1285" 2 3/4" 1.36" 0.1285" Standard Steel, Iron, Plastic 3024A253 5.07 4.30
29 0.1360" 2 7/8" 1.47" 0.136" Standard Steel, Iron, Plastic 3024A252 5.07 4.30
28 0.1405" 2 7/8" 1.46" 0.1405" Standard Steel, Iron, Plastic 3024A251 5.07 4.30
27 0.1440" 3" 1.58" 0.144" Standard Steel, Iron, Plastic 3024A249 5.72 4.85
26 0.1470" 3" 1.58" 0.147" Standard Steel, Iron, Plastic 3024A248 5.72 4.85
25 0.1495" 3" 1.57" 0.1495" Standard Steel, Iron, Plastic 3024A247 5.72 4.85
24 0.1520" 3 1/8" 1.69" 0.152" Standard Steel, Iron, Plastic 3024A246 5.88 5.00
23 0.1540" 3 1/8" 1.69" 0.154" Standard Steel, Iron, Plastic 3024A245 5.88 5.00
22 0.1570" 3 1/8" 1.68" 0.157" Standard Steel, Iron, Plastic 3024A244 6.21 5.27
21 0.1590" 3 1/4" 1.8" 0.159" Standard Steel, Iron, Plastic 3024A243 6.21 5.27
20 0.1610" 3 1/4" 1.8" 0.161" Standard Steel, Iron, Plastic 3024A242 6.49 5.51
19 0.1660" 3 1/4" 1.79" 0.166" Standard Steel, Iron, Plastic 3024A241 6.49 5.51
18 0.1695" 3 1/4" 1.78" 0.1695" Standard Steel, Iron, Plastic 3024A239 6.49 5.51
17 0.1730" 3 3/8" 1.84" 0.173" Standard Steel, Iron, Plastic 3024A238 7.39 6.28
16 0.1770" 3 3/8" 1.83" 0.177" Standard Steel, Iron, Plastic 3024A237 7.39 6.28
15 0.1800" 3 3/8" 1.82" 0.18" Standard Steel, Iron, Plastic 3024A236 7.39 6.28
14 0.1820" 3 3/8" 1.82" 0.182" Standard Steel, Iron, Plastic 3024A235 7.39 6.28
13 0.1850" 3 1/2" 1.94" 0.185" Standard Steel, Iron, Plastic 3024A234 7.39 6.28
12 0.1890" 3 1/2" 1.93" 0.189" Standard Steel, Iron, Plastic 3024A233 7.95 6.76
11 0.1910" 3 1/2" 1.93" 0.191" Standard Steel, Iron, Plastic 3024A232 7.95 6.76
10 0.1935" 3 5/8" 2.05" 0.1935" Standard Steel, Iron, Plastic 3024A231 8.24 7.02
9 0.1960" 3 5/8" 2.04" 0.196" Standard Steel, Iron, Plastic 3024A229 8.24 7.02
8 0.1990" 3 5/8" 2.03" 0.199" Standard Steel, Iron, Plastic 3024A228 8.24 7.02
7 0.2010" 3 5/8" 2.03" 0.201" Standard Steel, Iron, Plastic 3024A227 8.24 7.02
6 0.2040" 3 3/4" 2.09" 0.204" Standard Steel, Iron, Plastic 3024A226 9.83 8.34
5 0.2055" 3 3/4" 2.08" 0.2055" Standard Steel, Iron, Plastic 3024A225 9.83 8.34
4 0.2090" 3 3/4" 2.08" 0.209" Standard Steel, Iron, Plastic 3024A224 9.83 8.34
3 0.2130" 3 3/4" 2.07" 0.213" Standard Steel, Iron, Plastic 3024A223 9.83 8.34
2 0.2210" 3 7/8" 2.18" 0.221" Standard Steel, Iron, Plastic 3024A222 10.41 8.85
1 0.2280" 3 7/8" 2.16" 0.228" Standard Steel, Iron, Plastic 3024A221 10.41 8.85

Metric Size Left-Hand Drill Bits

Also known as reverse-flute bits, the flutes spiral in the opposite direction of other bits. They are for use in reverse tool operation—most commonly to remove broken screws. Jobbers' length are the most common bits and have the rigidity and length required for most applications.


Size Size Decimal
Equivalent O'all
Lg., mm Max. Drilling
Dp., mm Shank
Dia., mm Point Style For Use On Each
118° Point Angle—Jobbers' Length
Uncoated High-Speed Steel
1.0 0.0394" 34 9 1 Standard Steel, Iron, Plastic 29855A26 $9.07
1.25 0.0492" 38 12.3 1.3 Standard Steel, Iron, Plastic 29855A29 11.96
1.3 0.0512" 38 12.1 1.3 Standard Steel, Iron, Plastic 29855A31 11.52
1.5 0.0591" 40 13.5 1.5 Standard Steel, Iron, Plastic 29855A33 6.96
1.6 0.0630" 43 15.2 1.6 Standard Steel, Iron, Plastic 29855A34 10.06
2.0 0.0787" 49 19 2 Standard Steel, Iron, Plastic 29855A39 6.18
2.1 0.0827" 49 18.8 2.1 Standard Steel, Iron, Plastic 29855A41 9.15
2.2 0.0866" 53 21.5 2.2 Standard Steel, Iron, Plastic 29855A42 8.85
2.5 0.0984" 57 23.7 2.5 Standard Steel, Iron, Plastic 29855A44 6.02
Black-Oxide High-Speed Steel
3.0 0.1181" 61 25.5 3 Standard Steel, Iron 29855A51 5.40
3.3 0.1300" 65 28.7 3.3 Standard Steel, Iron 29855A53 8.53
3.5 0.1378" 70 31.3 3.5 Standard Steel, Iron 29855A54 5.86
4.0 0.1575" 75 35 4 Standard Steel, Iron 29855A56 6.60
4.2 0.1654" 75 34.6 4.2 Standard Steel, Iron 29855A57 10.39
4.5 0.1772" 80 38 4.5 Standard Steel, Iron 29855A58 11.16
4.8 0.1890" 86 42.4 4.8 Standard Steel, Iron 29855A82 12.07
5.0 0.1968" 86 43 5 Standard Steel, Iron 29855A84 8.44
5.1 0.2008" 86 42.8 5.1 Standard Steel, Iron 29855A59 13.03
5.5 0.2165" 93 47.1 5.5 Standard Steel, Iron 29855A62 14.44
6.0 0.2362" 93 48 6 Standard Steel, Iron 29855A63 11.04
6.5 0.2559" 101 53.3 6.5 Standard Steel, Iron 29855A64 18.86
7.0 0.2756" 109 59.9 7 Standard Steel, Iron 29855A65 14.38
7.5 0.2953" 109 59.3 7.5 Standard Steel, Iron 29855A66 24.58
8.0 0.3150" 117 64.6 8 Standard Steel, Iron 29855A67 18.49
8.5 0.3346" 117 63.9 8.5 Standard Steel, Iron 29855A68 31.39
9.0 0.3543" 125 69.3 9 Standard Steel, Iron 29855A69 23.75
10.0 0.3937" 133 74 10 Standard Steel, Iron 29855A71 29.60
11.0 0.4331" 142 80.8 11 Standard Steel, Iron 29855A72 36.61
12.0 0.4724" 151 86.6 12 Standard Steel, Iron 29855A73 45.21
Cobalt Steel Left-Hand Drill Bits

These bits provide more heat resistance than high-speed steel to maintain their sharp edges longer when drilling hard materials. Also known as reverse-flute bits, the flutes spiral in the opposite direction of other bits.They are for use in reverse tool operation—most commonly to remove broken screws. Maintenance-length bits are shorter and more rigid than jobbers' bits but longer than short-length bits.


Size Size Decimal
Equivalent O'all
Lg. Max.
Drilling Dp. Shank
Dia. Point
Style For Use On Each
135° Point Angle—Maintenance Length
Uncoated Cobalt Steel
5/64" 0.0781" 2" 0.88" 5/64" Split Stainless Steel, Nickel, Titanium 3474A11 $3.26
7/64" 0.1094" 2 1/4" 0.84" 7/64" Split Stainless Steel, Nickel, Titanium 3474A12 3.65
1/8" 0.1250" 2 1/4" 1.06" 1/8" Split Stainless Steel, Nickel, Titanium 3474A13 4.06
5/32" 0.1563" 2 5/8" 1.27" 5/32" Split Stainless Steel, Nickel, Titanium 3474A14 4.26
3/16" 0.1875" 2 7/8" 1.34" 3/16" Split Stainless Steel, Nickel, Titanium 3474A15 5.26
7/32" 0.2188" 3 1/8" 1.42" 7/32" Split Stainless Steel, Nickel, Titanium 3474A16 6.06
1/4" 0.2500" 3 3/8" 1.63" 1/4" Split Stainless Steel, Nickel, Titanium 3474A17 6.35
9/32" 0.2813" 3 5/8" 1.7" 9/32" Split Stainless Steel, Nickel, Titanium 3474A18 8.59
19/64" 0.2969" 3 5/8" 1.87" 19/64" Split Stainless Steel, Nickel, Titanium 3474A19 8.91
5/16" 0.3125" 3 3/4" 1.97" 5/16" Split Stainless Steel, Nickel, Titanium 3474A21 10.09
11/32" 0.3438" 4" 1.98" 11/32" Split Stainless Steel, Nickel, Titanium 3474A22 11.35
3/8" 0.3750" 4 1/8" 2.06" 3/8" Split Stainless Steel, Nickel, Titanium 3474A23 14.41
13/32" 0.4063" 4 3/8" 2.14" 13/32" Split Stainless Steel, Nickel, Titanium 3474A24 16.12
7/16" 0.4375" 4 5/8" 2.22" 7/16" Split Stainless Steel, Nickel, Titanium 3474A25 18.59
15/32" 0.4688" 4 3/4" 2.23" 15/32" Split Stainless Steel, Nickel, Titanium 3474A26 20.56
1/2" 0.5000" 5" 2.31" 1/2" Split Stainless Steel, Nickel, Titanium 3474A27 23.29

 

[Maniacmechanic1]

I have a few broken ones to remove in D-port heads.
That cast iron 1959 389 exhaust elbow also.
Sell them.

 

[T-Test]

Red wrench and liquid nitrogen is what I use to use until everything got regulated to death. Have you bought a bottle of acetylene lately? Can't get liquid nitrogen any more.

 

[Maniacmechanic1]

Red wrench and liquid nitrogen is what I use to use until everything got regulated to death. Have you bought a bottle of acetylene lately? Can't get liquid nitrogen any more.

I have an acetylene gas ax torch to use at work. No liquid nitrogen though.

 

[Grumpy]

Ive seen this done several times, and yeah, it works in many applications

 

[Grumpy]