Questions tagged [machining]
14 questions
17
votes
2 answers
What is crankshaft grinding and why is it done?
I saw a lot of YouTube videos referring to crankshaft grinding, while watching videos about working on crankshafts. I don't understand what crankshaft grinding does.
If we grind a crankshaft, then how does it stay compatible with the vehicle where…
Inquisitive
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11
votes
3 answers
What size hole should be drilled for an individual tap?
The other day while doing further work on my son's Subaru, I drilled a hole in a piece of angle iron then started using my 1/4-20 tap to cut some threads in the hole. The idea was to have a threaded hole which I can screw a bolt into to secure the…
Pᴀᴜʟsᴛᴇʀ2
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9
votes
1 answer
Machinist Straight Edge Tolerance
I want to purchase a straight edge which I can use to measure the flatness of heads & blocks and other such nifty things. My question is, what is considered a good tolerance for a straight edge? To make this a little easier, if I wanted to buy a 24"…
Pᴀᴜʟsᴛᴇʀ2
- 165,084
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7
votes
2 answers
How are crankshaft crankpin journals ground?
In looking at this question:
What is crankshaft grinding and why is it done?
@Pᴀᴜʟsᴛᴇʀ2 gave an excellent answer that got me thinking. First, lets include the same picture from that answer so we're on the same page:
When reconditioning the…
cdunn
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5
votes
1 answer
Just the straight facts; nothing edgy
In this question I asked about tolerances for straight edges. For this I have a followup question about length.
If I want to purchase a straight edge, I only want to purchase one straight edge which would cover most use cases (hopefully 90+% of all…
Pᴀᴜʟsᴛᴇʀ2
- 165,084
- 32
- 259
- 508
5
votes
1 answer
Which is longer lasting HSS-E or HSS coated wth TiN?
I'm just gonna purchase taps and dies for my most commonly used metric screws. I want them to last for as long as they can (not that they will be used so often, I just want them like that). I also will be hand cranking them, so actual high speed…
Dehbop
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5
votes
3 answers
Rotor replacement, one or both?
I work at an independent auto repair shop and we seem to have 2 schools of thought, first thought, Mechanic A, one rotor under spec's, the other rotor on the same axle is machinable, replace only the rotor that is at or under min and resurface the…
Danny
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3
votes
2 answers
Removing a welded nut
There's a nut welded on my countershaft and I don't like that.
How do I remove it while minimizing the chance of damage to the countershaft's threads, as damage would necessitate:
a. welding a nut on
b. splitting the cases
andrey
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2
votes
1 answer
Improperly installed valve guides
I am new at doing cylinder head work and accidentally installed 4 pre spiraled valve guides upside down, can I hammer them back out and reinstall them correctly or do I need to use new ones?
Paul
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2
votes
1 answer
Prepping freshly machined block for building
I'm building an engine from the ground up to swap into my project car. The aluminium block has been re-lined with ductile iron sleeves so the machinist sprayed them with white grease to prevent rusting.
There may be metal dust still within the…
MIL-SPEC
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2
votes
4 answers
Is there a hack to repairing a seized engine?
Last week I drove on the interstate for about 1 mile when my engine died. the oil light never came on but it was low on oil and a couple thousand miles overdue for an oil change. I had it towed to a shop who told me the engine was seized; they put a…
ItsJason
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1
vote
1 answer
What will happen if you attach the negative pole of welder to the rotor of the motor or the body , will that cause problem?
I have built a machine that rotates a cylinder to weld it, I have to attache a negative pole to the cylinder which is connected directly to the rotor of motor, the motor is controled by a vfd , will that cause any issue to motor and vfd or not?
Alyamin Smail
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1
vote
3 answers
Best way to fix (or hack) a warped exhaust manifold?
The front exhaust manifold on my 2002 Ford Escape is warped. The problem is the catalytic converter is integrated into the exhaust manifold so a new one is like $800 and you can't get them at either of the junk yards I go to.
I don't have the time…
user875234
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0
votes
2 answers
Why facing the head block?
I have recently came across a problem. One of the rocker fingers (the one that touches the valve stems, and have cam rollers) on my diesel engine head has broken. This resulted in the pistons hitting the valves due to the missed timings. The entire…
C--
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