LumberJocks

DRilling holes in end grain of plywood.

  • Advertise with us

« back to Woodworking Skill Share forum

Forum topic by MrRon posted 356 days ago 1169 views 0 times favorited 11 replies Add to Favorites Watch
View MrRon's profile

MrRon

2403 posts in 1746 days


356 days ago

Topic tags/keywords: question

I build large scale locomotive models. They can get quite large, like 5’ long x 15” wide x 16” tall. I build them following metal working techniques, but out of wood mostly. I have a situation where I want to drill 1/8” holes parallel to the plies of 1/2” (12 mm) Baltic Birch plywood (11 ply). The holes will go through 1/4” thickness , but centered and parallel (not perpendicular) to the plies. Machine screws will go in the holes to tie it to something else. This is something that I would normally use a metal for, but due to the size of the material, a metal would be too costly. The bolted joint won’t see any great stress. I could use glue, but I want it to be able to be disassembled. Do you see any problem with drilling those holes as I’ve depicted?


11 replies so far

View 404 - Not Found's profile

404 - Not Found

2544 posts in 1472 days


#1 posted 356 days ago

I don’t see any problem with what you are proposing, especially since the BB ply is void free. The wise thing to do would be try it on a scrap piece first and see how well it works.

View DS's profile

DS

2081 posts in 923 days


#2 posted 356 days ago

The drill bit will want to wander before it gets started. The plys will influence the bit some.
Best to use some kind of jig, or clamp your work into a drill press setup to get the holes drilled just where you want them.

A smaller diameter pilot hole will help a larger bit stay on course too.

My $0.02

-- "Hard work is not defined by the difficulty of the task as much as a person's desire to perform it.", DS251

View Loren's profile

Loren

6770 posts in 2151 days


#3 posted 356 days ago

Best way to do it is use a bushing to control flexing of the
bit so it drills on center.

Have you considered threaded inserts?

A threaded insert is bigger so you can use a larger, stiffer
brad point drill which will stay on center better than a little
wiggly 1/8” drill.

View DS's profile

DS

2081 posts in 923 days


#4 posted 356 days ago

Threaded inserts are slick—and a true machine thread.

-- "Hard work is not defined by the difficulty of the task as much as a person's desire to perform it.", DS251

View MrRon's profile

MrRon

2403 posts in 1746 days


#5 posted 356 days ago

Thanks for the replies. I had thought about threaded inserts, but I can go either way; insert or screw and nut. I will experiment and see which works best. I’m thinking an insert would tend to split apart the plies; looking at a 6-32 threaded insert with an OD of 1/4”. There wouldn’t be much meat left. I made a mistake. 12 mm BB is only 9 ply.

View Loren's profile

Loren

6770 posts in 2151 days


#6 posted 356 days ago

Also, check out cross dowels (barrel nuts).

View casual1carpenter's profile

casual1carpenter

353 posts in 978 days


#7 posted 356 days ago

Not sure about this myself but I wonder why no one suggested coating the drilled hole with CA glue to sort of harden the area that will form {accept} threads?

View Dan Lyke's profile

Dan Lyke

1455 posts in 2628 days


#8 posted 356 days ago

Completely different wood, completely different project, but this weekend we won the Bodega Bay Fisherman's Festival Wooden Boat Challenge with a boat where the seams were joined by drilling and screwing into the center-ply of cheap 3/8” construction ply.

I’d use a proper-sized taper bit and you should have no problems when the center ply is end-grain, it’ll be a challenge when the center ply is side-grain.

-- Dan Lyke, Petaluma California, http://www.flutterby.net/User:DanLyke

View Lee Barker's profile

Lee Barker

2161 posts in 1353 days


#9 posted 356 days ago

I like Loren’s barrel nuts idea. That allows for a little oversize holes, in case the bit wanders, but positive attachment. Brilliant.

Kindly,

Lee

-- "...in his brain, which is as dry as the remainder biscuit after a voyage, he hath strange places cramm'd with observation, the which he vents in mangled forms." --Shakespeare, "As You Like It"

View MrRon's profile

MrRon

2403 posts in 1746 days


#10 posted 355 days ago

Here is a sketch showing what I want to do. This detail takes place in 18 places on the model. The model is of an electric loco used by the New York Central RR. I posted this because barrel nuts won’t in this case. The CA glue is an idea that I can try. The BB is for the frame of the loco which measures approximately 6×50. Alum would be too expensive to use.

View MrRon's profile

MrRon

2403 posts in 1746 days


#11 posted 355 days ago

Dan Lyke, Thanks for the pictures; sure looks like fun. I lived in San Rafael from 1966 to 1998 and used to boat on the Bay area waterways. It got to be too expensive for me, so here I am in beautiful Vancleave, South Mississippi.

Have your say...

You must be signed in to reply.

DISCLAIMER: Any posts on LJ are posted by individuals acting in their own right and do not necessarily reflect the views of LJ. LJ will not be held liable for the actions of any user.

Latest Projects | Latest Blog Entries | Latest Forum Topics

HomeRefurbers.com

Latest Projects | Latest Blog Entries | Latest Forum Topics

GardenTenders.com :: gardening showcase