First build... come laugh at my mistakes. - Page 4

charles Tauber · #46 02-18-2021, 12:02 PM

Quote:

Originally Posted by DickHutchings

There's no better feeling than just running it through the drum sander, in one side and come out the other all done! I use 60 grit and run at the fastest speed the Intelesense will run. It still gums up a little but I have a roll that I can cut my own from and it's pretty quick to change it out when running rosewoods through it.

Perhaps, I should make this a separate discussion, but...

I've not been thrilled with the Delta drum sander I have. I like it better than my homemade one, but it isn't great.

I use 80 grit sandpaper on it. I find that it leaves very deep striations in the sanded surface, regardless of grit used. The sanded surface, regardless of grit, is nowhere near a finished surface. I have to sand and/or scrape the striations out, which takes 20 minute to 1/2 hour, at least. The striations are deep.

It takes me about 20 minutes to remove the old sandpaper and install new sandpaper - and that is using pre-cut strips. The last set of ziricote that I sanded with it gummed up the sandpaper so badly, so quickly, as to be a waste of time and sandpaper and deeply burned the wood: I ended up hand-planing it.

Do you have better success with your sander? Specifically, do you get a truly finished, sanded surface out the other end, or do you have to follow-up with sanding and scraping? Is mine just a lousy machine, or is that the nature of the beast?

warfrat73 · #47 02-18-2021, 12:30 PM

Quote:

Originally Posted by cobalt60

Sorry if you mentioned this already: I'd suggest jointing that back now, so that your thicknessing process also serves to even out any jointing imperfections.

Already joined before I started in on it.

cobalt60 · #48 02-18-2021, 03:25 PM

Regarding sanders, I'll state what might be obvious to some: There is a huge difference between "wide belt" vs "drum" sanders, and that difference is magnified as the width increases.

The proliferation of drum sanders (esp. the PerforMax and Jet models) seem to have standardized them as the non-production-house standard. In my opinion and experience, drums are a significant downgrade from wide-belt, particularly for the work done by luthiers. Wide belts have equal or better thickness accuracy, much better heat control, much better dust collection, much better anti-clogging properties, much better grit changing process, ... maybe more? Now that I'm typing this, I cannot think of a single reason I'd choose a drum if both machines were sitting right in front of me, tuned-up and ready to use.

Trouble is price and space, but a used & older wide belt can sometimes approach a new drum's price, and the size increase is mostly vertical.

Final consideration, though: A lot of those benefits are moot if you have patience and are removing 0.1mm per pass anyway

DickHutchings · #49 02-19-2021, 08:10 AM

My experience is the same as far as the finished surface. I don't even try for a finished surface, only thickness and I leave enough to quickly sand out with my random orbit sander. For the inside, I didn't try to get it perfect but remove the majority after the box is closed. I should get some 100 grit for my drum, it only takes a couple of minutes to swap it out using pre-cut paper. I wonder if that would clean it up.

warfrat73 · #50 02-24-2021, 09:06 PM

Well, I have the top and back to spec (or, as close as I'm going to get). I took to the back with a bit more assertiveness, and did my best to clean up the tear out with a scraper and RO sander. There are still a few little scars on the inside surface, but they're pretty minor.

Was having a bit of a hard time cutting the curves with the bandsaw, need to just take my time and make multiple cut, or pick up a narrower blade.

Also, on further inspection, the blade on my No 5 plane was pretty far off of square, that likely wasn't helping. Put some time into fixing that

Next up I'll set in on the sides.

ruby50 · #51 02-27-2021, 09:33 AM

I have a cabinetmaker friend a walk away and he has a 48", 20Hp, oscillating belt sander. The feed belt has a 3 HP motor. He does large slabs on it, and he charges me $20 to do whatever I want. He uses 2 grits of paper to get my stuff ready for 220 hand sanding - takes less than 60 seconds to switch belts. It is a stitch to watch .055 ukulele sides come through this massive machine. Maybe someone like this near you

Ed M

warfrat73 · #52 03-02-2021, 11:04 AM

Well, I mostly finished up my work board mold thingy.

And I started in thicknessing the sides. It's going a bit smoother than the back. Spent some more time working on blade geometry, and it seems to be doing pretty well. Working diagonally on the side plate seems to be the ticket. Am able to remove a fair amount without any big tear out, but it's still slow going.

I'm aiming for about .09" on the sides. I think that's about right for Bubinga. But that's a lot of wood to remove starting from .2". Just need to cultivate patience.

kmanuele · #53 03-02-2021, 01:33 PM

Quote:

Originally Posted by cobalt60

Sorry if you mentioned this already: I'd suggest jointing that back now, so that your thicknessing process also serves to even out any jointing imperfections.

The only downside is that a wide belt sander would need to be twice as wide (basically a 24" instead of a 12" or "industrial not home-hobby size").

Or a two step process: thickness each half to remove most of the wood and clean up all (4) surfaces. The sander will make both halves the same thickness, which is the best place to start when jointing.

With open-end (cantilevered) types of drum sanders (like a SuperMax), you can run wider pieces through in two passes. If the machine is adjusted correctly, there is very little deviation in thickness than cannot be fixed easily and quickly if necessary (I've only done this once, but it worked as claimed).

Kevin

kmanuele · #54 03-02-2021, 07:48 PM

Quote:

Originally Posted by DickHutchings

My experience is the same as far as the finished surface. I don't even try for a finished surface, only thickness and I leave enough to quickly sand out with my random orbit sander. For the inside, I didn't try to get it perfect but remove the majority after the box is closed. I should get some 100 grit for my drum, it only takes a couple of minutes to swap it out using pre-cut paper. I wonder if that would clean it up.

I keep 120 grit in my SuperMax almost all the time. It is aggressive enough, and leaves an almost-finished surface. I go to 80 grit or lower only when I need to remove a lot of wood, mostly for non-guitar projects -- though not happy with the finish. Likely unavoidable without an oscillating drum.

Have not had good luck with oily woods. Course grits, light cuts, high speed conveyor seem to help a bit, as does angling the piece to distribute heat over the width of the drum. I suspect the drum speed in this tool is just too high for these kinds of wood.

Kevin

DickHutchings · #55 03-03-2021, 02:23 PM

120 grit?? I can't imagine. Mine came with 80 grit and it will never go back on. You must be thicknessing non-oily woods like maple or something. I find the 60 grit gets me in the ballpark. Like was said above, full speed light cuts and fresh paper.

warfrat73 · #56 03-05-2021, 10:36 PM

Well, managed to get the sides thinned. And in a surprise development, managed to get the second one done in less than an hour. The extra time spent working on the plane helped.

Will get to bending soon.

Pretty good size pile of shavings.

warfrat73 · #57 03-07-2021, 08:16 PM

Welp, one of the sides was coming along ok... this was not that side.

charles Tauber · #58 03-07-2021, 09:35 PM

How thick is the broken side?

warfrat73 · #59 03-08-2021, 08:27 AM

It's at about .09". I guess I should have gone thinner. Hindsight... oh well.

I'm mostly bummed because I spent so much time on the back. I'm a bit torn between ordering another cheap Bubinga set just for the sides, and going to the EIR that I have on standby.

warfrat73 · #60 03-08-2021, 09:40 AM

Ok, so I"m probably not going to go buy another set of bubinga right now. At some point, well into working on the back, it occurred to me that maybe I should do the sides first in case I break one... live and learn.

The EIR set I have has a bit of an issue that I need to straighten out. One of the plates came pretty dished... I managed to get that mostly taking care of. But there's still a little bit of a bend in one spot that keeps the two back plates from wanting to line up right, it's pretty minor, and I think a bit of weight when gluing them up would probably address it, but it's making jointing a bit tough.

I sprayed down the offending area, sitcked and weighted it and it's been sitting over night. Hopefully that'll take care of it.