How does on press in small pins straight?

[Winegrower]

Of course that's a 4:1 depth to diameter ratio, maybe the hole wandered? It's a skinny drill. Maybe I was too aggressive in drilling. I didn't ram it in, but it was a slow process. I did use WD40. Perhaps pecking might yield a little better results?

Indeed, pecking is pretty critical with such small diameter flexible drills. I think if you just start drilling down, even slowly, the drill will likely drift off and keep drifting. Pecking more or less resets that tendency. Joe Pie has a good video talking about making deep straight holes, and pecking is an important factor.

 

[WobblyHand]

I'm going to try a slightly bigger drill size for the pin. 1.95mm. The heads of the dowels seem enlarged. Might be I'm trying to displace too much metal for such a small size pin. In any case, I will try out peck drilling.

 

[tq60]

How deep are the drilled holes?

Choke up the drill bit to where only 3/16 or less is protruding from chuck.

Peck drill, then extend another 1/8, Peck and repeat until done.

Sent from my SM-G781V using Tapatalk

 

[WobblyHand]

How deep are the drilled holes?

Choke up the drill bit to where only 3/16 or less is protruding from chuck.

Peck drill, then extend another 1/8, Peck and repeat until done.

Sent from my SM-G781V using Tapatalk

7-8mm deep for a 2mm diameter hole. Good idea for extending the drill that way. I'll try that tomorrow.

 

[machPete99]

Make sure the pins are chamfered or rounded on the ends.

 

[WobblyHand]

Make sure the pins are chamfered or rounded on the ends.

Good idea. I did buy chamfered pins from McMaster. Looked at each pin before insertion to have the better chamfer towards the hole.

I think the hole might be too narrow and perhaps not deep enough. Maybe the displaced metal is filling the hole so it can't be pressed home and then the head of the pin mushrooms. Or I have drill wander. I'll work on it today.

 

[mmcmdl]

Hey Wobbly . Just saw this . One of the things we learned as apprentice tool makers was to grind a small flat on the pins before pressing them in . This lets the air escape from the hole . Not really needed for larger things but this helps with the small stuff .

 

[OTmachine]

PCP, if you are talking about the airgun. PP700SA in 22 cal.

I got that from GTA. Nice air gun. Made some new delrin valve seals for one of the members. I was referring to the pressed in pin acting like a piston in the tight hole not leaving any exit for air when installing pins.

 

[WobblyHand]

Hey Wobbly . Just saw this . One of the things we learned as apprentice tool makers was to grind a small flat on the pins before pressing them in . This lets the air escape from the hole . Not really needed for larger things but this helps with the small stuff .

Thanks for the idea. These pins are pretty small, so I guess I could rub the side against a stone using a finger tip. 2mm diameter and 8mm long pins, not much to hold onto.

 

[WobblyHand]

I got that from GTA. Nice air gun. Made some new delrin valve seals for one of the members. I was referring to the pressed in pin acting like a piston in the tight hole not leaving any exit for air when installing pins.

Good point on the pin trapping air. I'll try making a flat on the pin to let the air out. I could drill further so the holes become through holes, but that's like gun drilling. Afraid that the hole would wander from true due to the high length to diameter ratio.