Renewing pin punches

[browntown]

Stupid question, how does one grind old pin punch tips perfectly flat?

I have some old starretts that I've used and abused and the tips are deformed. I was just going to use the bench grinder but I wasn't sure that I would get a nice flat and perpendicular tip. My other idea was to chuck up the punch in the drill press and push it into a grinding stone or sandpaper.

Am I overthinking this?

 

[Matt018]

hmm a belt sander may be the best choice, I'm not sure, although I look forward to what others say

 

[wornoutoldman]

Bench grinder. Dress it on the side of the wheel.

 

[Kevin54]

If all you have is a bench grinder, stack up some scrap 2x4's at the side of the grinder. Lay the punch on the 2x4's and roll the punch back and forth while dressing the punch on the side of the wheel. Same way if you have a belt sander, roll the punch to get it perfectly flat.

 

[browntown]

you guys are the best

 

[Russian]

Valve grinder.

 

[larry_g]

I chuck up the punch in the hand drill and spin it while running it against the grinder wheel. Make sure that the punch is perpendicular to the grinder shaft so as not to leave a point on the punch. I do not use the side of a grinding wheel as it will weaken the wheel and lead to explosive failure.

lg
no neat sig line

 

[wornoutoldman]

I chuck up the punch in the hand drill and spin it while running it against the grinder wheel. Make sure that the punch is perpendicular to the grinder shaft so as not to leave a point on the punch. I do not use the side of a grinding wheel as it will weaken the wheel and lead to explosive failure.

lg
no neat sig line

Yikes! Do not use my intial suggestion unless your grinder wheel is designed for side grinding! Thanks Larry

 

[Robbie UK]

Drill press for me using an old sharpening stone (the flat knife sharpening kind) to gently grind against.

 

[MechManiac]

I used a bench grinder recently and it worked fairly well. I rotated the piece against the wheel.