JoeTBM 

No issue at all, just wanted to make sure you understood there is a difference between the two methods

dabac

Sometimes it will really bind near enough permanently. I’ve stripped the threads of several crank arms over the years. These days, if I really want to save the crank, I’ll drill the pedal spindle out.

Amt0571

I've left it al the LBS. Working from home while having a kid leaves me little time. They told me they're not sure they can remove it but will try

I'm going to drill the spindle if they don't manage to remove it, but it's my last option as I'd like to avoid risking damage to the crank.

dabac

If you’re pushing enough torque in it to crack a vise, you’ve already gone well past the point where damage can occur. It wouldn’t take much skill or tools to have a better chance of removal by drilling than torquing by now.

Amt0571

Well, I'll let the LBS try. My father's vise was a cheap 20 year old one, the one on the LBS seems stronger.

Any recommendation about drill bits? I assume the spindle is steel, so I suppose I'm going to need a good drill bit.

rydabent

That vice must have been made in China.

aggiegrads

You can break any vise if you try hard. Unfortunately, lots of people try hard. A vise is not a press, or an anvil. A vise (with the notable exception of a blacksmith’s post vise) is not meant to have the workpiece hit by a hammer. A vise should not have a cheater bar put on the handle or have the handle beat with a hammer.

There are people who love vises as much as we love bikes. He is an article by a guy on how to not break a vise:

https://mivise.com/not-break-vise/

WizardOfBoz

If one way is right, and the other wrong, then your bike will always be half wrong... !

I think that the suggestion about turning the pedal in the correct direction refers to the fact that the right hand (drive side) pedal has right-handed threads (counterclockwise to remove) while the left-handed pedals (non drive side) has left handed threads (clockwise to remove). So its different depending upon which side pedal you are removing.

WizardOfBoz

Possible, even likely, but other countries made crappy stuff, too. Still, I'm concerned about the hammer handle right next to the vice base. Vices aren't made to be hit! Vices aren't made to hold stuff that you're gonna hit! (See the video above on "how to break a vise"). So even if this was a fine old American-made Wilton or Yost or Athol Starrett vise, the hammer handle makes the hairs on the back of my neck stand up...

Here's a blacksmith's leg vise. This one's mounted on a post, but you can also mount them to a wall or bench. You got one of these, hammer away (tho generally you hammer DOWN, and not side to side).

https://spaco.org/postvisewouttable.jpg

Amt0571

I didn't hit the vise with the hammer. Trust me.

It was a cheap 30y/o vise though as I remember seeing it since I was a kid 😅

WizardOfBoz

I find that reassuring! So you broke the vise with arm strength? Wow!

Any progress on the pedal?

Amt0571

Yes, it broke with arm strength.

I'm still waiting for the LBS to call me back. They told me they would try to apply penetrating oil overnight first.

If it doesn't work I'll try to drill it, and if everything fails I've found new identical cranks for 49€ in stock.

woodcraft

You might like this:

aggiegrads

Seen it. That guy knows to break a vise. Cheater bars, hammers, and using the vise as a press. Same way most vises break.

It hurt my soul to see him abusing that Prentiss. Even though it had already been abused in the past.

woodcraft

I wonder how mine would stack up.

aggiegrads

About like mine.

Thruhiker 

I would drill it out. If it's a 9/16 bolt use a half inch drill bit. Or one even closer to 9/16 if you have one. 17/32 maybe? In my experience that usually weakens the bond and then the bolt threads out. I've never had to drill a pedal bolt though so I might be incorrect. Just be sure the drill doesnt mess up the threads of your crank arm.

SalsaShark

Just to make sure, you are looking at the back of the installed pedal spindle when you insert the allen wrench. So the drive side pedal would need the allen screw to turn clockwise to remove the pedal when looking down the tool at the "inside" of the crank arm, where the tool is inserted into the threaded spindle. Non drive side would turn counter-clockwise with the allen to remove the pedal.

Amt0571

Yes, I tried to unscrew it in the correct direction. Trust me. It's not the first pedal I removed.

In fact at the LBS they tried in front of me and couldn't move it either. That's the reason I left it there and I'm waiting for them to call with the results while hoping for the best.

Amt0571

Good news from the LBS. They managed to remove the pedal with a vise after applying lots of penetrating oil. A little bit of the thread stripped, but nothing significant and it holds a new pedal without issues.

Great!

WizardOfBoz

That guy is Jason Marburger. Originally a welder in a steel mill, the guy was inventive and came up with some products. Site is interesting: www.fireballtool.com. Marburger apparently has had some success: his R&D shop is 5000 square feet and he has some pretty amazing stuff. Shop tour is .
Three ameliorating factors on braking that Prentiss. First, Marburger built his own custom vise that is stronger than the Prentiss. See .
Second, he actually repaired the Prentiss. Or, rather (since he's a creative guy) he improved it. Purists won't like it, but its a pretty amazing job, making a ~75 yo vise better than new. The third factor is that the vise had been broken and repaired before, so it wasn't pristine.
See here:

WizardOfBoz

Thanks for reporting back. You'd be surprised (or maybe not) at the number of folks who write in for help and then never report how the problem was solved. Your being considerate and closing the loop is appreciated.

halb 

We were all waiting. Is he gonna' get that pedal off?

Amt0571

Lots of people spent their time to try to help me. It's the least I can do. I have yet to see the extent of the stripped thread though. They told me it holds a pedal ok, but better not to replace pedals often.

Based on the pic they sent me, it seems that on the inner side of the crank, around 1/5 or 1/4 of the thread is missing, but the rest is intact. Difficult to appreciate in a picture though.

WizardOfBoz

The general rule is that, for like metals (steel pedal axle in a steel crank arm), one diameter of thread engagement gives you most of the strength you need. Put another way, any more than one diameter engagement doesn't add much strength. But if your crank is alloy, the loss of threads is of more concern.

For a fine, vintage crank (like a Campy Nuovo Record from the 70s) its sometimes worth trying to repair threads using things like thread inserts (you drill out the original hole to a larger diameter, tap threads in the bigger hole, with the same pitch (threads per inch) as the original, and put a coiled spring in the hole. The spring is made from diamond shaped wire and so the outside of the spring screws into your new, larger hole, and the inside of the spring has the same diameter as the original hole). Not worth it for most cranks. But if the balloon goes up, it sounds like you've sourced replacement crank arms anyway.

Here's a pic of one type of thread insert. In these, once the insert is screwed into the crank, the four prongs would be driven down to lock the insert in the crank.