Drilling small holes in plywood and thin ply cutting bits

[denmanmarine]

Hi all,

I was looking to get a recommendation for a bit to drill small holes in plywood. Hole sizes will be 2 or 3mm, sometimes 1-200 per sheet and thickness of material varying from 3mm to 12mm.

Before everyone says I should have got the pneumatic drill option with the PRS Alpha,my budget didn't go that far.

Any suggestions?

Also I have watched the shopbot video on cutting ply and the compression bits seem to to be the tool of choice for ply but what about thin plywoods from 3-12mm? It would seem that the compression bit would not work as intended in thinner stuff. Any recommendations for cutting thin okoume ply?

Thanks in advance.

Andrew

[bleeth]

Use a drill bit and turn the rotation speed down to 12-18 hundred. In other words-make your tool emulate a drill press. Depending on a couple factors you may need to peck drill as you can't have your bit getting too hot. Through drilling 12mm ply with a router bit spinning at high speed can easily start a fire. You will need a collett to match the bit or a bit holder that will hold the bit and fit your collett. If you are stuck with a router bit, use a down-cutter, low speed, and multiple pecks. Don't leave it unattended. Pause after a few holes and check the bit. If it is hot then you are spinning too fast or plunging too slow.

For thin ply a downcutter is best. The cleaner your spoilboard and better your holddown is the cleaner the bottom cuts will look.

[Bob Eustace]

Andrew have a look at brad point carbide drills. Amana have these for around $18 a throw. As Dave pointed out you will need to budget for another collet. These are usually 8mm in these sizes. I run the spindle at 6,000 and use peck drill. The forum put me straight on running these as I was super worried about balance with the bit flat on the shank! In case Dave has gone to bed I think he meant to say upcut for drilling. There is one guy here who super glues a drill into a bit of 1/2" brass and runs at the slowest speed. I have not tried this. The brad bits though never seem to wear out with "accidents" the only thing killing them!

[knight_toolworks]

you mean like the parts below? 1/8" bb ply cut with a 1/16" downcut bit and drilled with a 1/16" bit no tabs.
as for drilling I get circuit board drill bits they are solid carbide and cost about 5.00 each with a 1/8" shaft. I have drilled 10s of thousands of holes with a bit and never broke one. They drill clean and in one pass and at 8k plastic aluminum (go a bit slower) wood and whatever. they don't clog or need peck drilling unless going the full depth of the bit and they don't seem to get dull. one time I drilled 50,000 holes in lexan with no problem on one bit. mcmaster car sells them
I cut these parts at 1ips 10k rpm in a single pass sometimes I get 14 hours out of a bit sometimes 4 you never know. but they usually go a long time.

http://i154.photobucket.com/albums/s266/knighttoolworks/posting/null_zps70863062.jpg (http://s154.photobucket.com/user/knighttoolworks/media/posting/null_zps70863062.jpg.html)

[j_richardson]

I need to do a similar thing, though I'm making a vacuum table and want to drill 1/8" diameter holes. I have 1/4" and 1/2" collets for the ShopBot, which is a PRS with a spindle. The McMaster circuit board drills have a 1/8" shanks. Where can I get a collet to accept this shank size. Or is there an adjustable collet available? Or is there a drill bit available with 1/4" collet and 1/8" drill dia.? I really need to branch out so that I can use other diameter cutters, like 3/8", or whatever I need to do the job.

[bleeth]

Mcmaster also has collets (both ER25 and ER20) that will hold a 1/8" bit.
For best accuracy and least runout spend a few extra bucks and get the higher quality ones and not the "wow I found some really cheap ones on e-bay" variety.

[scottp55]

Monday "drilled" 500 holes in C-90 torrefied ash using a profile toolpath inside the line with a .003 offset on a .25" hole using a spiral ramp to a depth of .35". Used a .117 upspiral fishtail end mill from PreciseBITS, 1.1,1,14K. Cut very fast, no splintering,clean sidewalls, leaves a .02 "dome" at bottom of cut because of the bit design. This wood powders a little but was getting good chips,good chip ejection and the bit was cool after 350 holes in (10 minutes? not at that computer). Might do it different if doing different wood or ply. Anybody, I'm a newbie and just liked the fact that it took half the time of peck drilling and could adjust the diameter of the cribbage peg hole as the pegs are wood and tolerances were horrible on different batches.
Worried about spindle, anything wrong with this approach?

[scottp55]

oops .125" diameter hole.

[j_richardson]

Mcmaster also has collets (both ER25 and ER20) that will hold a 1/8" bit.
For best accuracy and least runout spend a few extra bucks and get the higher quality ones and not the "wow I found some really cheap ones on e-bay" variety.

Thanks. I checked McMaster and see only ER16, ER32, and ER100. Maybe they no longer carry the 20 or 25 (?). On the web I found Tormach for $12.75, Lyndex for $34.00 (at Amazon), and MSC for $38.18. I'm really ignorant about collets, so I don't know what to look for.

[dlcw]

Hi all,

I was looking to get a recommendation for a bit to drill small holes in plywood. Hole sizes will be 2 or 3mm, sometimes 1-200 per sheet and thickness of material varying from 3mm to 12mm.

Before everyone says I should have got the pneumatic drill option with the PRS Alpha,my budget didn't go that far.

Any suggestions?

Also I have watched the shopbot video on cutting ply and the compression bits seem to to be the tool of choice for ply but what about thin plywoods from 3-12mm? It would seem that the compression bit would not work as intended in thinner stuff. Any recommendations for cutting thin okoume ply?

Thanks in advance.

Andrew


Andrew,

I regularly drill holes in plywood, melamine, MDF and solid wood. I use boring bits not standard rill bits. Set the spindle speed to 6000rpm and plunge to 1ips. I don't use the pecking process because the boring bits have nice open flutes which allow chips to clear nicely. I drill partial holes as well as through holes and have been very happy with the results. Super clean, top and bottom.

[Bob Eustace]

Thanks. I checked McMaster and see only ER16, ER32, and ER100. Maybe they no longer carry the 20 or 25 (?). On the web I found Tormach for $12.75, Lyndex for $34.00 (at Amazon), and MSC for $38.18. I'm really ignorant about collets, so I don't know what to look for.

Jed, forum member Gary Beckworth sells these at competive prices and top quality. Also has Onsrud bits.

[bleeth]

Sorry about that. Techniks brand is reliable. Instead of ordering through Amazon make up a lit of some other bits you need and call Ballew direct. They give discount for multiple piece sales. Their guy on the phone will help you do what is needed to get the discount.
Enco is also good, as well as the suggestion to deal with Gary Beckwith. Forget the 12 buck one-that's likely cheap chinese and could result in more runout than you would like.

[wberminio]

I would also get Widgetworks pressure foot for cutting thin ply.
No need for a hold down-just tape the edges.

[j_richardson]

Jed, forum member Gary Beckworth sells these at competive prices and top quality. Also has Onsrud bits.

Thanks, Bob and Dave!