Oil the pin joint?

Hello. I noticed that I am increasingly having a tougher time unfolding my straight razor. Does anyone apply mineral oil to the pin joint to make it rotate better? If so, how do you apply it both outside and inside the scale?

Thank you

Applying mineral oil to a carbon steel blade is always a good practice and it should be done every time you finish shaving, clean the blade and store the razor.
If you are noticing your razor does not rotate like it used to be, it can be there is rust in the pin and hole.
Check it out and if this is the case, you of course need to remove rust.

How do you check if there is rust? On the surface it doesn't look like it's rusting. How do I check places that are covered/hidden?

Also, any recommendation for a mineral oil?

I am afraid you need to remove pins to check it out. If you did not tighten pins up and unfolding the razor seems to be harder, rust can be the case.
You can also use some rust remover liquid, but you should consider they also have a corrosive function and this could damage scales' material.

Take a piece of white paper and slip it in between the scales after you spray them with something like WD-40 which will loosen the rust if there is any...

The white paper will be thin enough to get between the scales and the tang and if there is rust you will know PDQ

Adding to what has already been said, you can try Glen's recommendation with the thin type of dental floss and examine what you see.

Do you clean between the scales after use? Also, I've gotten into the habit after shaving is to wipe down the razor and strop it a few times. Personally, I know its called wet shaving, but to cut down on the cleaning I have to do, I try not to wet my razor if possible.

As per the tightness, I'd consider it more beneficial than looseness...unless it's dreaded rust.

Yes, what they all said.

Sooner or later H2O in some form gets into the pivot. BUT water can't go where oil is. Even if you have rust, oiled rust...can't rust any more.

OVER tightness however can lead to a broken scale, as I did recently after tightening up a pivot (then snap-when i pulled the blade open-dang). But LOOSE is always dangerous.

Look up some of the "bushing" and restore threads to see what happens to a pivot hole after decades of use (and not much oil). I use the same oil as i use on my strop, which is neatsfoot. That way I only "need" one oil and there's cannot be cross-contamination.

Yeah, it's wet-shaving, but keep that razor as dry as possible. If you gotta shower-shave, use a DE.

I cant compare their oil to any other , its the only one I have, bought it with my razor , but so far I think its doing the job. when my scale broke the other day I didn't see any rust ,,, no rust is good news! tc

I use Ballistol spray lubricant on my straight razors after shaving. It's been recommended here on SRP before.

I like it.