Disc sander question about trueing up…
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Hi everyone.Thanks for all the insightful responses in the “How long to leave clamps on glue-ups” thread.
I commonly make mitered frames out of 3″ wide oak.It is harder than heck with my tablesaw miter jig(similar to Gary Rogowski’s in the quicktime video) to get perfect joints off the saw.I try to clamp out the error by tightening the heck out of my steel band clamp.It works to some extent but they still aren’t perfect(once stained the mitered joint stands out,ideally it should disappear to some degree).
I’ve made a shooting jig complete with a Krenov style handplane I also made.I still can not get a perfect mitered joint.The plane rocks,imperceptively,and pre-empts getting a perfect fit.
I have decided to splurge a couple of hundred bucks on a disc grinder to true these miters up.It seems like a cinch from the magazine articles out there I have seen.I also like to experiment around with metal to some degree so I am sure I can use the disc grinder for other things also.
My questions are has anyone any experience using these grinders for such trueing up.Do they really work well in this application?Any suggestions or tips?
Also other than the obvious advantage of size does a 12″ disc grinder give better results than the more commonly available 6″ and 9″ ones.Obviously a 12″ disc turning at the same rpm motor speed will have greater speed at the edges of the disc than the smaller discs.Is that in certain circumstances advantageous.Thanks tons as always Roland.
Replies
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You will get better results with a mitre saw and a good blade.
Jack
*Roland -Have you made a sled for your table saw?Also consider getting a 10" plate for the TS onto which you can stick PSA sandpaper on both sides.
*Mike,yes I have a sled.It is like the one in the video by Mr.Rogowski FWW used to show here.I am aware of those grinder type inserts one can purchase for the table saw,however,I'm hoping eventually for a production type set-up.I hate doing set-ups.I suppose I'm lazy like that. Perhaps a miter saw,like suggested,is indeed the way to go.It is just that I wouldn't have much use for a miter saw other than miters.A grinder,in my particular workspace with my habits,would I think be more versatile.Thanks tons all.Roland.
*Don't the pro's shops use a slicer? Saw it then slice off 1/64".
*Hi Roland,Miters can be frustrating. What are you using to set up your 45° angle with? Any decent TS should be able to produce an accurate miter, I know talk is cheap..... it took me all day once to cut out a simple picture frame! For setting up 45° jigs I like to use a 45° drafting square, I believe they maybe called a 90-45-45. Don't give up! This is partly why woodworking is so fun, it's a @#$%^&* challenge.....Dale
*I prefer a sanded 45 º joint, no splintering and you get to sneak up on a perfect fit.... but most of the smaller disc sanders will need some tuning to get this level of precision.... consider building one. I had a machine shop turn a 16" x 1/2" piece of aluminum, mounted it to a piece of 1" shaft, couple of pillow blocks and some "left over ply" and a motor and I have an indespensible tool.
*No offense to anyone here but after spending most my life in pattern shops, I can tell you there is no easier way to get good fitting miters than a disc sander. As mentioned, the machine must be in good tune. Also as mentioned, this allows you to sneak up on the fit. The nice part about it is you can cut the joint on a bandsaw first and you don't get any splintering on the bottom side as you often do with table saws, chop saws and the like. I have used the Lion Trimmer before and found that it must be scary sharp, and you need a superman grip to keep stuff from slipping. For all you doubting Tomas's out there, try it for a while, you may be surprised.
*Thanks everyone for the excellent input. Trialnut I am sold.Sign me up.That is all I wanted to hear.I have doubts about those choppers or guillotine like setups being able to handle oak(thick and wide stock at that) alot without getting dull quickly.Frame shops,I would wager(I have never worked in one though)chop or nibble away at mostly painted pine or painted poplar.To a cutting blade I would say that is a heap easier load. Any hints about sneaking up on a perfect fit?I am thinking cutting the miters on the tablesaw first and then a couple of swipes at the disc for each cut.Would that process be easy enough to do by rote,i.e., without checking, or would one need to constantly check fit with the frame clamped up square.Thanks for your and everone else's input.Roland.
*Roland,I don't use my disc sander for accurate miters since I can usually accomplish them with my sled fixture or my Lion trimmer. However, I do own a Delta 12inch disc/6inch belt sanding machine. This I use primarily for dressing metal, as you indicated you would like to do. I find it indispensible. At least, I really don't know what I would do to replace it's function. I can get accurate miters in steel and brass using this machine, so I can't think of why it wouldn't work in wood. Also, as trialnut said, pattern makers use them (my father was one of these guys, he had two 20inch discs) and get great results (although perhaps it is not "pure woodworking"). The sander/grinder is a very valuable addition to my shop and I recommend it highly. Oh yea, if you grind metal on one of these, the dust will make your wood very nasty. And, grinding steel produces sparks. I've started a couple of fires in a shop-vac using it. Be careful.
*Jeff"not pure woodworking"? now I'm insulted ;~)RolandWe usually scribe an accurate line with a knife (X-acto w/ #11 blade works good) then sand to the line. If you watch the line as you are sanding, when you reach the edge of the knife cut you will see the wood "erode" and can adjust to be dead on to the center of the cut. That would be very hard to do with a pencil line but is quite easy with a knife line. Take some pine and scribe some lines on it. Darken these lines with a pencil sharpened to a flat point, and practice till you feel comfortable with the process. Then try it on some miters. The secret is in careful and accurate layout. Once you have done it a while it becomes second nature and you will be adjusting very little.Have fun with it.Rich
*Jeff and Trialnut thanks again for the input. Jeff are the miters you cut 3/4 or 7/8" thick?I didn't think those guillotine trimmers were capable of wide and thick stock.Most people make frames out of 1/2 and 5/8 thick stock,however I have to make thicker ones.The thinner frames I think lack substance... being less substantial somewhat. Trialnut pattternmakers may not do alot of joinery,however,in my book if you can make gears and sundried stuff out of wood you can do about anything with the material. I got it in my head awhile back to make myself a pair of shoes.Shoes,in general,are very cheap but the type I like,handmade in Italy ain't cheap.I've sewn leather before,no problem,so I figured all I needed to do was rough out a last on my bandsaw and then rasp it to final shape...afterwards stretch some soaked leather over it,and voila a $300 pair of Cole-Haan Moc-toe loafers. I didn't succeed,or haven't yet.It has been in limbo quite some time.Making a last,something a patternmaker would have no problem with,is unbelievable complicated I think.Patternmaking takes tons of skill with a bandsaw and rasp.Roland.
*Roland,I haven't used the trimmer all that much even though I've owned it for quite some time. However, I recently installed an ash handrail 3/4" high by 2-1/4" wide and used the trimmer. It cut very smoothly and accurately. One beauty of this cutter is on site trimming with no dust.
*In reading these comments, I see that one critical item has been omitted. The angular joints may be perfect,but if the opposing sides of the frame members are not EXACTLY the same length,at least one of the joints will fail to clamp up.¬¬¬¬¬¬¬¬¬PAT¬¬¬¬¬¬¬¬¬¬¬
*MajorYou beat me to it. I was just about to add that very important bit of info. If at all possible sand or trim both sides together. Tape them or somehow fasten them together so they will be exactly the same size when done. Do the same with the top and bottom. This example would be for a picture frame or something similar. This is one of the first things I learned as a patternmaker. Make them together, they will be the same. If you can't work both pieces together, then set stops.Roland, Let us know how this works out for you.Rich
*I've used all the above methods on wood and metal and the sled method with a good crosscut blade should do it all in one step for wood. I spent a number if years as a tech for woodmachines and I had this one commercial frame shop I would go to every once in a while to tune up their saws. Their shear cut miter trimmer was sitting in the back gathering dust once they went with the saw method. A Pistorius double miter saw for the 45 degrees and a commercial set up for the radial arm saw for octagons which is essentially the same idea as a sled except you move the saw instead of the material. Tear out was no problem as all the stock was prefinished and was up to 8" wide.http://www.pistorius.com/amiter.htmlAll the above mentioned methods work but I found the sled to be a simple one step method that guaranteed perfect fits. I used to have a Lion trimmer and a huge one like thishttp://woodcentral.com/shots/shot116.shtmland I got rid of both of the trimmers once I had a nice sled that worked.The Major is right on with the comment about the length. If you go with the miter shear you should set up a length gauge if you want true production.
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