I bought a bunch of boxes the other day and it was only when I was using a spade bit to cut a sound hole in the top of one that I realized it was pressboard and not the plywood I expected. The hole came out a little wonky but no matter, the guitar plays just fine.
I went to inspect a few of the other boxes and discovered many of them have pressboard tops too. I was planning to make a few acoustics with fancy cut f-holes using a hand coping saw and my Dremel router bit. That an be challenging even when working with a nice material. Is it even possible to cut pressboard cleanly with these tools? Should I consider different tools? Or just not even bother?
I can always flip them upside down so the wood bottom becomes the sound board.
Hi Ducati, what I would try, and what I do, is to use the type of spade bit (in a drill press preferably ) that has the cutting or scribing "wings" on the outer edge. This scribes the hole before the actual cutting face contacts the material and starts cutting. Before going too far I turnover the top and come in from the other side, and continue right through. I also find it a good idea to clamp the fibre board to a thicker backboard so than the point of the spade bit has a firmer/deeper hole to locate into.
If sawing by hand I would use a fret saw instead of a coping saw. It normally has finer blades and a deeper throat for better access.
Hope this helps, Taff
Although I have not ben making cbg's for very long. I was a carpenter most of my life and have worked with mdf or pressboard quite a bit. I hate to say it but your paddle bits don't have enough bulk to make a hole in PB cleanly. You could try drilling a 1/16th pilot hole then let the drills weight slowly drill through, but you are still going have some tear out. Placing a block of scrapwood underneath will also help. The faster the drills rpm' are the more chatter marks you will have at the holes sides. I would recommend getting a few forstner bits, good quality ones, not harborfreight theirs does not have a good side cutting edge.
Your coping saw will do just fine, it'll cut like butter. Just don't stop to make your turn, you will create preasure on the blade and board causing tear out. As always a light touch and a even preasure will do wonders. 18 or more teeth per inch luck on your batch of boxes.
You may also want to use an exacto knife to score as deep as possible before routing. Just take your time with it. I also on paper lids found that after scoring, a thined down glue or clear coat of some kind will penetrate into the fibers and help bond them together. The problem with the presswood is if you aren't careful, is bigger tear outs(chunks).
I agree with Kool Dog Hooch. Scoring a great way to keep it from chipping/cracking when you cut. Of course, scoring something like an f hole isn't easy, but take your time and that may help.
Sharp Xacto knife.
My preferred way to cut a soundhole in a pressed board top of a Cigar Box is to use the knife to cut the paper holding the pressed board on the box and use it as a template to cut out a new plywood top, drill a soundhole, screw it on to the box and throw the pressed board top in the trash. I know, I'm a smarta**, my wife tells me often.
Then what was the point of buying the box? ;) I build the boxes for many of my guitars but it's way easier and quicker to have a box to start with. Also, I like the tops of a few of these boxes so I want that to be part of the finished guitar.
Hi, I cut mine as described in this thread. Draw the outline rom a template of the desired hole shape, scribe with an exacto knife, drill suitable size holes at the junction of any two lines where they intersect [aids in turning the blade cleanly and easily] cut just inside the line with my fretsaw. I then sand the sawn surface and slightly bevel the outside edge to give the paper a clean look, and in the case of the soundhole in the photo, blacken the inside edges.
Regarding replacing the top / lid of a cigar box. Doing that I know can improve the sound of a guitar when using a less that ideal cigar box, but one could also photocopy the lid, print it out on paper of choice and paste it to the new lid. Thus getting a better sounding box with the same looks as the original.
Still, way too much work. Next time I’ll just buy better boxes!
Hi again, it all depends on the reasons different folks take up this creative pastime. Some to make money, some to have something cheap to play or as a gift for somebody, and some (like me) it's all of the above.
Its a chance for me to keep the grey matter working, creating and solving, designing and experimenting. I don't think about If tasks are quick or slow or hard or easy.......well I'm not real keen on easy.
l believe you get back what you put in.
Very true my friend. I guess this somewhat speaks to my bias here: I bought the boxes to have some quicker, easier builds than the last few where I built the boxes myself. As with many things in life, patience and persistence can always yield good results.