Need to shorten bolt 1/8"

[PoorOwner]

What is your preferred method of grinding the bolt down?

I have bench and angle grinder.

Bolt is M12

My only requirement is not to overheat it because there is already Thread locker on it. It is ok to keep dipping in water to cool as I grind?
I would like to get that chamfered tip so the bolt can start easier. I seem to have a hard time threading it in if it don't grind off some of the first thread?

 

[B_Bimmer]

Put a nut on before you grind, taking it off when you are done will ease future installation.

 

[Bring Spares Along]

I use a hacksaw. Run a nut on first and use it to clean up the threads after cutting. Then use a file to taper the end.

 

[LXCam]

Why don't you just add a washer

 

[T45]

3mm off, so I would do like the folks above and use a nut on the threads meaured up about 3mm and leave it there. that will act as a thread chaser when it comes off. then

-- use a hand file to de-bur and taper after main removal is done, taking care to keep the first thread clean and straight, use that bolt again to chase and a thread file if needed

-- use oil, cutting fuild, aqeus some other suitable lubricant to keep it cool. a hacksaw will work to shorted the mainr part of the metal just fine if you want to go that route.

-- normally, I don't worry about preapplied loctite, one can strip it and use normal stuff just fine. the temp control is really to not mess up the metalurgy

 

[slow_mow]

Why don't you just add a washer

This is what I would do if possible. If not, nut, hacksaw, threadfile/die.

 

[dutchgray]

I would probably just file it.

 

[Wamsutta]

I use a little Dremmel cut-off wheel.

 

[Jarhead0408]

Hacksaw and a thread file have done well by me.

 

[Schurkey]

Die grinder and fiber-reinforced cutoff wheel. Dress the final thread on a bench grinder--or--with the side of the cutoff wheel. Using the side of a cutoff wheel is not "officially" recommended, but would work OK if done VERY carefully.

HOWEVER, this being GarageJournal and all, I feel obligated to say that you should purchase a plasma cutter, and just blow the end off the bolt.

 

[gdocktor3]

Well, pick your poison... Dremel, grinder, bench grinder, hacksaw, file, or plasma torch. They all work, but which are you most comfortable using?

 

[ron in sc]

preferred method to shorten would be to mill it down.

 

[bcradio]

HOWEVER, this being GarageJournal and all, I feel obligated to say that you should purchase a plasma cutter, and just blow the end off the bolt.

This right here is the way to go. Anything less is not the correct method

 

[geartow]

1/8 is not there a cutter for bolts that size on wire crimpers?

 

[Leaflessshadetree]

HOWEVER, this being GarageJournal and all, I feel obligated to say that you should purchase a plasma cutter, and just blow the end off the bolt.

Gonna need a mill to shorten it then over to the lathe for the chamfer. We're talking 3 phase here and many hundred amps. Better head to the electrical section but read up on the codes first (there will be a test). Don't skip the section on welders cause you're gonna need one after you remove too much.

BTW: The preapplied thread locker probably came from china so it's no good, will be just fine or could be the best stuff ever.

 

[Superbec]

1/8 is not there a cutter for bolts that size on wire crimpers?

sure.. for a metric 12 bolt ..

the plasma cutter would be nice to watch ...

guess the conundrum spoiled when someone mentioned a washer ... now the poorowner is driving around looking for a washer but it seems all the washers come in standard ... oh boy

 

[rlitman]

... no threading of a nut on in advance (to maintain the integrity of the threadlocker)...

+1

I normally grab the threads to be removed in the vise and hacksaw off the rest, but 1/8" doesn't leave you anything to grab AND cut.

Rather than grind (which I might do if I were feeling lazy), I'd probably grab the bolt head in the vise (or grab the whole thing in the soft jawed vise if it has a round head), and file off the end with a really large (18" or so) ******* file. Then switch to a fine single cut file to finish it up.

I always finish with a file. With the bolt sticking up, your file should be inclined 30 degrees from horizontal to run the chamfer all around. I finish off by using a tiny triangle file to clean up any burr inside the last thread.

Gonna need a mill to shorten it then over to the lathe for the chamfer. We're talking 3 phase here and many hundred amps. Better head to the electrical section but read up on the codes first (there will be a test). Don't skip the section on welders cause you're gonna need one after you remove too much.

BTW: The preapplied thread locker probably came from china so it's no good, will be just fine or could be the best stuff ever.

WHAT?!? Forget the mill and just chuck it in your 6-jaw chuck in the lathe, adjust your steadyrest to hold it in position, and part it in place. Then use your compound to cut the chamfer. Finally, setup your threading gears to take a pass over the threads to remove the chinese thread locking compound (you may have to move the steady rest to do this), and apply Loctite 8675309 thread locker with the proper applicator specified in the manual, while ignoring the color of the thread locker, as it is meaningless.

 

[Todd.Brock]

It's guys like you that give this place a bad name. Everyone knows a 9 axis CNC is the only way to deal with this .. gawd- what's with you people ...

 

[nh_yota]

I'd just buy a shorter bolt.

 

[bwringer]

I'd just buy a shorter bolt.

Metric bolts come in 5mm length increments, sometimes 10mm. OP wants to remove 1/8", which is about 3mm.


To answer the question, bench grinder, clean up with thread file, done in under five minutes.

 

[nh_yota]

Metric bolts come in 5mm length increments, sometimes 10mm. OP wants to remove 1/8", which is about 3mm.


To answer the question, bench grinder, clean up with thread file, done in under five minutes.

I was being a wise ***.

I would use a bench grinder just because it's easier to grind off an 1/8 of an inch than it is to cut it with a hack saw (at least IMHO). Throw on a nut or two before you grind it and hold it with a vise grip.

 

[Roberts210]

I've done this in many ways. My least favorite way is with a hacksaw. Doing it with a hacksaw boogers up the end threads something fierce. An 1/8th inch isn't much. I've done it by holding the bolt with a pair or pliers or vice and using a belt sander. I've also done the same with an angle grinder. And I've done it with my 6X48 Delta belt sander also. I've even held the bolt with a pair of pliers and ground it down on a concrete driveway--that took some time but I was away from my shop and had to improvise.

 

[R W]

Screw the nut on, clamp it in the vice, hacksaw 1/8" off, may need to touch the end up with a file or grinder.

 

[cja245]

I use a hacksaw. Run a nut on first and use it to clean up the threads after cutting. Then use a file to taper the end.

This is how I do it, but ideally with a porta band.

 

[Finky198]

Why can"t you just reapply thread locker after cutting the bolt??? This is way over complicated. Run a nut or thread chase on, grind off excess, remove said nut/chaser to repair threads, and reapply loctite....

Jeeezus the job could have been finished in less time then it took to start this thread.......

 

[nbpt100]

All of these methods mentioned work. Except for the hand cutters. 12mm is close to 1/2" Those cutters usually go up to a #10 screw. And they don't work very good on Stainless steel.

If I had a full machine shop available I would chuck it up in the lathe and be done in a couple of minutes you will have a nice square cut and chamfer. All in the same set up. No need to use any other machine or refixture the part.

Use what ever you have available.

 

[bmwrd0]

Drill it out, retap it for a proper size such as 1/2", then go to the bolt bin and select the correct length bolt.

No, seriously don't worry about the old thread locker, just grind or saw the part you don't want, re-locker it and move on.