Does anyone have suggestions for how to make really accurate perpendicular holes in 4x4s for large (1 1/4) dowels?
I'm building a wood swing set for my kids based on one I had as a kid. The play towers at either end are made out of a grid of vertical 4x4 posts with horizontal dowel rungs connecting them. Basically, like a bunch of vertical wood ladders all connected together. The rungs will be only structural element keeping everything together and square, so I want to make them as accurate as possible.
The only idea I've come up with is to use a plunge router with a 1 1/4" bit and build a centering jig for it. I'm hesitant to make the holes with a regular drill, since I'm not sure how to make a good jig for a bit that big and even with a jig, I'm not sure it would be square enough. I have a drill press, but it's in the basement and I can't get the posts down there or bring it up (it's an old floor model that's too heavy to move).
As a side note, I'm planning on using pressure-treated 4x4s and dowels and Titebond 3 to glue them in.
Mac - I have had good success with a large Forstner bit on posts like that.
I put the bit in an electric motor 1/2" drill and stand on the post with
the drill between my feet so I can hap-hazzardly judge the vertical position.
if you have some 4x4 scraps, try it to see if that will work for you.
if you are unstable standing on one post, put 3 or 4 together to make a
wide platform for stability.
.
I was thinking of a guide and started to draw one for you but a quick search yielded this video - (but don't use your chisel upside down like he does :wink
Take a 3 1/2" wide by 1" or greater thick scrap and nail or screw end/side plates on it.
Drill a centered 1 1/4" hole through it using your drill press.
Straddle the 4 X 4 where you need the hole.
Drill away......
John, I'm okay at eyeballing right angles, but I don't think I'm nearly that good yet.
David, I love the guide idea. I've only got one drill though, so I'd have to figure out how to make that piece removable. Also, it's a cordless drill (ryobi), so would drilling 100+ 1 1/4 inch holes wear out the motor?
Woodnthings, I like the simplicity of that jig. Does it do enough to keep the bit squared to the wood so that all of the rungs will be square? Also, does the bit start to eat at the sides of the jig and create wiggle room?
Is there a reason the router idea wouldn't work? Also, am I worrying too much about keeping the holes perfectly perpendicular?
Sorry if I'm asking obvious questions. I'm still pretty much a newbie.
John, I'm okay at eyeballing right angles, but I don't think I'm nearly that good yet.
David, I love the guide idea. I've only got one drill though, so I'd have to figure out how to make that piece removable. Also, it's a cordless drill (ryobi), so would drilling 100+ 1 1/4 inch holes wear out the motor?
Woodnthings, I like the simplicity of that jig. Does it do enough to keep the bit squared to the wood so that all of the rungs will be square? Also, does the bit start to eat at the sides of the jig and create wiggle room?
Is there a reason the router idea wouldn't work? Also, am I worrying too much about keeping the holes perfectly perpendicular?
Sorry if I'm asking obvious questions. I'm still pretty much a newbie.
The Forstner bit doesn't have full length side cutters like a twist drill so it won't warble out the guide hole. It may not survive a hundred holes, but it should work fine for 20 or 30. The Forstner has about a 1/2" side cutter edge, so it will be guided fairly well in a 1 1/2" thick drill guide. The guide is so simple, so just use it with confidence.
:vs_cool:
For what it's worth, here's a basic drawing of what I'm making (sketchup and PDF). I'm probably going to go with a 4x3 grid of posts (not 5x4) and I'll leave out some of the rungs to create some bigger spaces to play in, but this is the general idea.
I'm still not sure if I'm going to bury the ends of the posts or just run some horizontal 4x4s around the outside as a base.
I cannot speak to any of their effectiveness. I'm an eyeball kind of guy and can get pretty darn close- close enough for the several jungle gyms I've built for the grandkids.
Mac - eventually, as your projects grow, so will your list of tools.
now may be the time to visit some pawn shops in your area to
look for a 1/2" VSR electric drill with low RPMs that give high torque.
well worth the investment - especially in this project.
with a hefty electric drill and a sharp Forstner bit, I bet your hand/eye
coordination improves tremendously drilling all those holes freehand.
(and IF you did make a jig, you would probably be ditching it after half a dozen
holes - and going freehand for speed vs accuracy.
it's a Jungle Gym for kids - not a piece of living room furniture - don't overthink it.
looking forward to seeing your project filled with yelling and squealing kids !!
(that could care less if the holes and dowels were perfectly aligned - or not).
looking closely at your initial design, I would suggest you go over/under the
dowels vs going through them at the intersections.
this is my "Go To" drill for anything that needs some extra UUuumphh that
a battery drill can not provide. the side handle is CRUCIAL to safe operation.
glue ?
personally, I would use stainless screws to hold it together.
kids grow up and outgrow such things.
if you ever wanted to take it apart, glue would make it pretty difficult.
or - when the time comes - chop it up for firewood.
I'm a bit late to this, but when I need perfectly straight holes I either use my drill press, or a drill guide like this. I've had one for years. It doesn't get used much, but when it does it's usually the only thing that will do the job. If I'm boring posts and have more than one hole to drill, I make a jig from wood to saddle the work and attach this drill guide to it. Perfectly straight or perfect angled holes every time. There are two sizes of these. This is the larger one.
I’d second John’s idea about assembling it with SS screws. If you do use dowels, make sure they’re up to the task. Some can rot in a hurry out in the elements.
Getting all the holes to align with full length dowels may be a challenge. You may want to consider shorter dowels that butt up in the 4x4s. If you went with screws, it would mean double the number.
Our kids are 3 and 1 1/2 (and we might decide to have another), so hopefully it's going to get many, many years of use before they're done with it. At that point I think I'd rather chop the dowels with a reciprocating saw than unscrew all of them.
My plan was to have each rung be a separate dowel and sink each one an inch or so into the post, rather than trying to go all the way through and run one continuous dowel. I should have clarified that earlier.
It sounds like everyone is on board with using a drill versus a router, but just for my own curiosity and general education, why would you not use a router?
Our kids are 3 and 1 1/2 (and we might decide to have another), so hopefully it's going to get many, many years of use before they're done with it. At that point I think I'd rather chop the dowels with a reciprocating saw than unscrew all of them.
My plan was to have each rung be a separate dowel and sink each one an inch or so into the post, rather than trying to go all the way through and run one continuous dowel. I should have clarified that earlier.
It sounds like everyone is on board with using a drill versus a router, but just for my own curiosity and general education, why would you not use a router?
A plunge router has a flat base, so that gets you perpendicular right away! :smile2:
https://www.amazon.com/uxcell-Cutti...s=1.25+planing+bit&qid=1582728092&s=hi&sr=1-6
Then with an end cutting bit, in 1 1/4" diameter .... you can plunge in to a predermined depth with a stop set and make your holes. The use of two small wood scraps or aluminum angles bolted to the base for edge guide will center the router's base on the 4 X 4 easily.
I was just looking at forums talking about what wood to use and stumbled across a photo of someone building what I'm talking about. It even looks like it probably was taken way back around the same time I was a kid. I think you all already got the gist, but couldn't help sharing this find.
Lookee there, them holes ain't all that straight! :surprise2:
I guess a large mallet will fix a few degrees of mis-alignment? I would still try to make them as perpendicular as possible and if that meant using a jig, OK, then. :|
The problem with most if not all electric drills, and I own around 15 of them, is that there is no straight line on the motor housing you can use as a vertical reference. All you have is your drill bit and if that's a Forstner, it ain't very long. :sad2: So you end up guestimating what is vertical/perpendicular that that's even more difficult when drilling horizonally, just my opinion. Those small, round bubble levels might work for the end of the housing, I donno, I've never tried one?
I'll get one out and see where I could "mount" it that wouldn't interfere with cooling or get easily knocked off.
Get yourself a 1/2" drill and a Forstner bit and go to work, after a couple holes you will have figured out how to line it up and by the time you are half done you will be an expert. 😀
Easy for a guy out in BC to say......:wink:
I think our OP is looking for more precision as in "fine woodworking" approaches. Those of us with more confidence/experience would probably just "get after it" as you say. I don't blame him for looking at different approaches because who knows, we may stumble on something that's a clever and accurate solution. :surprise2:
Simplest jig would be the one suggested in post #4 by woodnthings, use a 1 1/2" thick board, that will be high enough so you can eyeball the drill bit shank to keep it centred in the pilot hole so the hole is straight if using a Forstner bit.
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