Modify rear sight notch

First topic message reminder :

Hello Folks,

My new gun is very nice, but the rear sight notch is not wide enough for me.  How would you go about cutting the notch a bit wider?  I hope to do this without removing the sight from the slide.  Is it feasible?

Thanks, Tom

Thanks gents. OK from Mr Chapman we know a 3/32" width file is out there. For me to order from that manufacturer online I'll need to buy 8 of them. We have a tool store on the other side of town; I'll bring our son and a pair of calipers over there sinceI haven't found an easy button online.

Edit: this looks like a promising alternative:
https://www.mcmaster.com/product/4251A18

I'm sure you'll find something locally, but this one is over-the-top perfect. 2.5mm thick, two safe edges.

https://www.leevalley.com/en-us/shop/tools/sharpening/files-and-hones/70693-auger-bit-file?item=51W0620
https://www.corradishop.com/sharpening-files-c-2_10/auger-bit-riffler-file-p-808

@Jack H - I had never heard of an auger file, what a great tool.

Get an ignition point file from your local auto supply store.

I have a point file sitting on my dwell/tach...but do any pars counter guys even remember what they are?
Another option would be a set of jeweler's files, less than 10 bicks on Amazon.

A chainsaw depth gauge file may be an option that may be available local, though could be too wide. Can also use adhesive back sandpaper on a combination square blade as well.

I have a set of 6 Nicholson hobby files, the part no. is 42030L.  The flat file is safe edge and is about .05" thick.

Not sure if you buy them individually, but they are handy to have.

Some rear sight blades are very hard and Swiss files won’t work so well. I had that problem on a Ruger Security Six. 
Diamond gritted Swiss files can do the trick. Harbor Freight has some inexpensive sets. Can’t remember if they have one in the set with a non-gritted edge.

Thanks guys. I ordered a set of points files that will be here tomorrow. I'm expecting at $8 shipped with tax a pair that they will be garbage and I'll end up visiting the specialty tool store.

I used a round chainsaw file I had in the garage 3/ 32nds I think. It was perfect and I filed it a little deep that gave it a semi-round bottom also. Worked great for me, I swabbed on some Brownells cold bluing for protection then sooted both front and rear. Made it a lot better for sustained fire stages.
 Stan

The $5 ignition points file set on Amazon worked fine, took less than 10 minutes to open my Rock River rear blade notch width from 0.113" to 0.125" (the width of the front blade). A mini "womp" job. Looks better against the wall in dry fire. I'll revisit in a few weeks whether I want to go further. Thanks all