MPVic
Member
Wondered if anyone has utilized slightly larger, letter size bits to allow for painted blanks. For instance for 7mm tubes, the letter "K" bit should give a bit more room for paint.
Drill bit for painted blanks
- Thread starter MPVic
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Woodchipper
Member
I drill with the recommended bit and have no problems.
Of the 1000's of tubes AND barrels that I painted (use canned spray paint), that has happened to me about 10 times if that. Not that I am any expert. I have not used large bits to eliminate the rare issue. I have used very, very very slightly narrower bits to achieve a more snug fit. It didn't work-out well. I don't have an answer that woudl not create too much slop.
Woodchipper
Member
I use a cotton swab (Q tip to some) and acrylic craft paint for the inside of the blank.
ed4copies
Local Chapter Manager
If you use spray paint, you are unlikely to need to change the size of the hole.
If you use a "brush on", you MAY need to increase it. There is no standard for how much larger than the tube the hole is.
So, if you need to increase, keep a chart nearby. In some cases, you can increase by 5 or 6 thousandths, in other cases the next larger bit is over ten thousandths (.01) larger and may be sloppy. (For example, the cap on a churchill and cambridge has very little material left when drilling as directions state--if you make the hole larger, you are VERY LIKELY to blow out the cap!! DAMHIKT!!!)
One such chart, that is printable, is here: https://crafter.fastenal.com/static-assets/pdfs/9701309_TapDrillPoster.pdf
I have several copies of this type chart in my shop and office to answer questions about tolerances.
FWIW,
Ed
If you use a "brush on", you MAY need to increase it. There is no standard for how much larger than the tube the hole is.
So, if you need to increase, keep a chart nearby. In some cases, you can increase by 5 or 6 thousandths, in other cases the next larger bit is over ten thousandths (.01) larger and may be sloppy. (For example, the cap on a churchill and cambridge has very little material left when drilling as directions state--if you make the hole larger, you are VERY LIKELY to blow out the cap!! DAMHIKT!!!)
One such chart, that is printable, is here: https://crafter.fastenal.com/static-assets/pdfs/9701309_TapDrillPoster.pdf
I have several copies of this type chart in my shop and office to answer questions about tolerances.
FWIW,
Ed
egnald
Member
I typically have the drills that are one or two steps up and down from the specified drill and I do on occasion use them when I plan on, as Ed says, "brush on" inside the blank. I too use a chart that shows the drill sizes, but I also made one up of my own, specifically related to pen tube drills for various kits. I also cut and paste from my chart into custom instruction sheets or "quick reference" sheets along with my notes for many of my favorite kits. - Dave
PS I think there may also be a drill bit reference chart or two that Wayne has put in the Resources on IAP.
PS I think there may also be a drill bit reference chart or two that Wayne has put in the Resources on IAP.