drill blow outs

[ahoiberg]

does anyone have a suggestion for limiting the blow out on the bottom of a blank with a 10mm drill bit? It seems when i did 7mm ones, i never had the problem but moving up to 10, there's been some decent blow outs at the bottom of the blank being drilled.

one thing i tried was to put a scrap beneath it, this doesn't seem to help. it just seems like the blank gets lifted up slightly when it reaches the scrap piece and the blowout still happens.

perhaps cutting the blank a little longer than need be and trimming off the blown out edge?

any other suggestions would be appreciated.

thanks,
andrew

 

[wood-of-1kind]

Don't drill completely through, stop before the drill exits(blank) fully. Cut the end prior to full penetration with a mitre saw or band saw.

-Peter-[]

 

[huntersilver]

For me, drilling short and cut off with the bandsaw works well.

Also, if you pull up on the drill and let the waste material
exit frequently helps too[]

 

[Rifleman1776]

As said, don't go all the way through. Drill to depth required, or slightly over in the full piece of blank. THEN cut to length.

 

[Pipes]

Key #1 SLOW the drill speed down I use about 550 to 600 rpm's on blanks I am afraid will blow out . ! Speed + presure= heat = blow outs and cracks go in and out a LOT to clear the bit . BE SURE the bit is really good and sharp . That a IMHO cure MOST blow outs and cracking .. But thats my opinon from experiance.

Good luck

 

[ahoiberg]

thanks a bunch for the ideas y'all.

 

[Rmartin]

I always cut my blanks longer than needed, drill, then cut to lenght just a bit longer than the brass tube, then after glue up, I use a barrel trimmer on the drill press just deep enough to make the brass shine.

 

[Ron Mc]

Interesting. I have my drill press at the fastest speed it will go and don't have a problem. Just remember to drill a very little bit at a time and I like to have my shop vac sucking the shavings away from the hole as I am drilling.
What kind of drill bits are you using and what kind of material are you drilling?

 

[leehljp]

Dull and even "fairly" sharp bits are contributing factors to blow out too.