Top and Back Thickness Before Joining
For my first mandolin build (Crystal Forest flattop plans) I thickness sanded the top and back pieces to nearly final thickness before joining. I'm going to hand plane the next set(s) that I use, and I'm curious about how close to final thickness I should go before joining (using the rope and stick method for gluing).
I can see advantages to thinning as much as I can now in terms of avoiding issues with planing against the grain on a book matched back, but I suppose it's a little more forgiving to leave some material to work down after gluing. I did recently score a Stanley 112 scraper plane which should be useful in final thicknessing.
Thanks. I'm grateful for all that I've learned here already.
Re: Top and Back Thickness Before Joining
If you can sharpen and use that plane well you won’t have any difficulty with either choice.
I would ease the edges of the blade very slightly though.
Re: Top and Back Thickness Before Joining
You mean to round the corners a little? I've come across that before in reading about the scraper planes. Makes sense.
Re: Top and Back Thickness Before Joining
It mostly comes down to how accurately you and your clamping system align the halves. If you can get perfect alignment you only need enough extra thickness (above your final thickness) to clean away glue and sand the wood for finishing. If there is a chance of slight misalignment of the halves a little thicker is in order.
Personally, for flat tops, I usually thickness the halves maybe .010" to .020" thicker that I want my final thickness to be. I use a thickness sander, so the amount of work involved in reducing to final thickness is negligible, so I figure I might as well allow for a little misalignment, though I try for none.
Re: Top and Back Thickness Before Joining
That's great to read. I had good luck with the stick and rope clamping setup so it sounds like I can do pretty much the same. Thanks!
Re: Top and Back Thickness Before Joining
I do no thicknessing at all prior to jointing, then put the jointed top/back through the thickness sander. Also using the string and wedge method of jointing here.
Re: Top and Back Thickness Before Joining
A thickness sander certainly makes things easier. I used a Shopsmith conical disc for thickness sanding on my first build, but it's hard to hold the stock flat while sanding. I thought I'd try my next couple of builds going old school by planing and scraping to thickness. Luckily I'm using relatively straight grained wood this time. I think it will be easier to get close to final thickness with more narrow pieces prior to gluing but wanted a sanity check.