Replies

1. 
   gpwest | May 15, 2003 08:05am | #1

   Ralph,

     Did you dry clamp the project together first, before cutting the biscuit slots, to test the fit?  Also, what size is the project?

    It is for the problems you describe that I avoid using biscuits in miter joints: the biscuits add strength, but they also increase the chances for a sloppy fit.

       GP

1. 
   user-168285 | May 16, 2003 02:51pm | #11

   Yes I agree that the biscuits are not the best way to support a miter. I usually spline the miters. However these were molded on the outside edge and a spline would not work. I had enough meat on the inside to use a biscuit and tried that. The work piece is 15 by 25. I am going to check for loose runners on the gauge and then add some sand paper to stop movement. Then I will probably make a sled for miters. My shop is full of sleds for this and that. I was going to look for more gauges and dedicate two for miters. I wonder if I could dedicate one miter for right hand use and then simply flip the board or turn it around for the other miter? I will sort this problem out. Thankyou for your help.

1. 
   corners | May 16, 2003 05:12pm | #12

   I think we stayed with a table saw because that was the original question. Chop saws can be good - I cut most of mine with a chop saw - but modern chop saws have some problems. For example put a piece of 3/4 inch thick wood on the chop saw table and lower the blade. At the beginning of the cut the blade is entering and leaving the wood through the top of the board - lots of chance for tear out and chipping. The geometry of the saw is designed as a compromise to allow the saw to cut 2x6's with a 10 inch blade. Put a couple of 2x4's against the fence and another on the table to move the workpiece up and away from the table and fence - now lower the blade and the teeth enter the top of the workpiece and leave through the back - far less chance of tearout and chipping. This is the way a real miter saw is designed. However you won't be able to cut stock wider than about 3 inches depending on the saw. Work up a setup to suit the work you need to do - be imaginative, tools are a fun game!

   With the table saw sled I like the workpieces to angle away from me. This puts the entry of cut closer to the supports and makes for less turning moment to twist the workpiece. But it depends on the stock you are cutting. 

   Speaking of chop saws, I'm off right now to pick up a new Makita LS1013. I was given a gift certificate and if I add a few bucks...

   My old chop saw is going to have it's fence removed and a table with 22.5 degree supports added for those 8 sided frames.

   PS - I cut most all of my miters on a dedicated double blade, double motor miter saw which is fixed at 45 degrees - that's all it does. I can cut and join a 4 sided frame in less than 5 minutes.

1. 
   Jeff | May 16, 2003 11:53pm | #15

   Corners

   Never seen one.

   Who makes it?

   Jeff

1. 
   corners | May 17, 2003 04:31am | #16

   There are a dozen or so companies making double miter cutoff saws - 2 in the US are

   http://www.ctdsaw.com/

   and

   http://www.pistorius.com/

2. 
   Jeff | May 17, 2003 02:51pm | #19

   Thanks Corners

   Now I know what your talking about.

   I had something different pictured in my mind.

   Jeff

2. 
   SgianDubh | May 15, 2003 08:20am | #2

   Where are the gaps? Are they on the inside of the mitre, or on the outside? Are they on one face, or both faces? Are you making one corner, two corners, three corners, or a four sided frame? And if it's the latter, do you only find the problem at, and after, assembly time? Slainte.

   Website                                   The poster formerly known as Sgian Dubh.

1. 
   Steinmetz | May 16, 2003 12:37am | #3

   Try to 'spline the miters with a contrasting hardwood.  Add a length of straight 1x3 to your miter guage. Set miter guage to exactly 45 degrees to the left cUT OFF EXTRA WOOD.

   Buy another miter guage and repeat for right hand cut.  Once both are set up, don't re-adjust, but do glue on a strip of medium coarse belt sander material to the 1x3's. (but not within 1/8th in of the end (To protect the blade.

   I have two 'dedicated' miter guages such as these and don't need wood filler.

   Most mitering problems are caused by slipping workpieces (Sand belt stops that)  another cause is blade is not perfectly vertical (Set at 90 degrees)

   Most importantly,is the blades paralelism.

   It must be exactly paralell to the tables miter groove

   A good trick to insure accuracy is to make some sample test angles from dry hard wood to reach the side of blade and the front of miter guage. 90/ 60/45/22&1/2/

3. 
   forestgirl | May 16, 2003 03:37am | #4

   In my limited experience, once you get past "tuning" the saw and testing cuts (2 45's = 1 90), movement is certainly the most frequent culprit.  Once I built an auxiliary fence for my miter gauge and stuck sandpaper onto it, my miter problems pretty much disappeared as long as I'm sure to hold the stock perfectly still going past the blade.

   My miter gauge has adjustments to snug the bar into the slot -- this is another source of movement, and it really has to be eliminated.  As far as sanding goes, I know alot of WWers touch up their miters with a sander, but it's always caused me more problems than it solved.  More practice, or a better machine I guess.

   Is it safe to assume that your stock is flat and square? 

   forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl   ;-)

1. 
   user-168285 | May 16, 2003 05:08am | #7

   Thanks for the tip on the movement of the wood as it passes the blade. I thought of this and then canceled that thought out. However the sand paper sounds like that is what I need. Along with one of the other suggestions is that I purchase a couple of extra miter slides. I can then apply the sand paper and set the miters up for left and right and when I get them set. Don't use them for anything else. Yes, I agree that the sanding is a problem. It caused me more problems anyway. My project is a base for a wine rack for the home that requires the base to be mitered. The size of the base is 15 by 25 inches. I have a 45 and 90 degree plastic lay out tool that I got at the office supply store in the city. I am not certain how accurate that is either. At the present time I use a right hand miter gauge and when I need to cut the other miter I flip the board over and run it back through. I suspect that is not a good idea either. Since I posted this note. I have had several responses and each has something that I can use. The only bug-a-boo that I have ever ran into in wood working is the 45 degree miters and they have given me fits. Nothing looks to novice as to see a nice piece of furniture with gapped miters that have been filled. Thank you for the help.

   My name is ralph [email protected]

2. 
   user-168285 | May 16, 2003 05:13am | #8

   Hello,

   Thankyou for the response to my miter problems. I will check for slop in the miter gauge slot. I need to get me some extra miter gauges that I can dedicate to miter work. Add some sand paper. Eliminate the disc sanding for the really does open up pandorra's box.

1. 
   corners | May 16, 2003 06:12am | #9

   Skip the miter guages and make a 45 degree sled. Have it run tightly with 2 miter slot runners. Make sure the top surface of it is precisely parallel to the table saw surface. Make sure the back side of your workpiece is dead flat and has no twist. If there is any twist in any piece you may be able to join the first 3 corners but the last won't line up. Make the fences against which you position the workpiece adjustable at first and screw them down tight when you have a good cut. Install some suitable Destaco type clamps to make sure the workpiece doesn't move. Use blades to suit miter cuts - not thin kerf because of deflection. And cut at a very uniform feed rate because the very nature of cutting at a 45 degree angle deflects the blade away from the obtuse side of the workpiece as the acute side gives way.

   And if all else fails visit a skilled picture framer and have your cuts made. The framer should be using a double miter cutoff saw - 2 blades - 2 motors - 1 cut. Just put the piece on the table and step on the pedal - then go join it soon before the humidity changes and the miter swells more at the thick part than the thin part.  From the wood movement point of view a miter is not always the best choice.

   The experience of more than million miter joints.

1. 
   BG | May 16, 2003 01:32pm | #10

   Corners,

   Good information, thanks.  One or two questions, I'm going to make a new sled with some MDF that will utilize two runners.  Which way should the 45 angle face, to cut from the inside of the stock out or outside of the stock in? (hope that makes sense)... I've seen sleds going both ways and does either way minimize tear out?  Also, blades?  and suggestions?

   Interestingly, no one is suggesting the chop saw as an option, is there a reason?

   thanks 

2. 
   forestgirl | May 16, 2003 06:37pm | #13

   A question and a suggestion for a possible alternative.

   Question:  Do you know the various tests for checking 90* and 45* cuts in your stock?  While the drafting triangles and such are indispensable, the geometric testing of cuts is also.  You haven't mentioned whether you use the tests or not, but I don't want to assume you don't know how to do them (For instance, 45* miter, flip one piece and form 90* corner, test with square.)  When you're doing miters, you need to check for 90* to fence, 90* to table, and 45* to miter sled.  Different test for each thing.  Let us know if you need these described.

   Alternative:  Buying extra miter gauges is certainly a good idea -- the thought has certainly crossed my mind -- but you can also buy one very, very good miter gauge to which you can add sub-fences with sandpaper and zero-clearance slots as an alternative.  I use an Incra 1000 (~$89).  Once it's set to 90* to blade and table, it's flawless, the miter bar adjusts for a snug fit, and I have a sub-fences that I add for miter cuts and other zero-clearance needs.  The sub-fence has 90* cuts in it, and 45* in each direction, nice layer of sandpaper and mounts and dismounts quickly in the miter gauge's slots. forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl   ;-)

1. 
   corners | May 16, 2003 11:39pm | #14

   Of course what counts is that the 2 angles add up to 90. Doesn't matter if one cut is 44 degrees as long as the other is 46 you'll still get a perfect 90. So when you make a sled make sure the 2 sides equal 90.

1. 
   forestgirl | May 17, 2003 05:50am | #17

   True, true.  There's that "right angle miter gauge" gizmo that in the Woodcraft and Rockler catalogs.  Cut the first miter on one side, the second on the other side and even if it's a fraction of a degree out of alignment, it should add up to 90*.  I dunno, though, the bar looks kinda cheap in the pictures.

   Seems like it would be easy enough to make one in the shop that attaches to one's own miter gauge.forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl   ;-)

2. 
   user-168285 | May 17, 2003 08:14am | #18

   hello,

   I also bought an incra miter V27 today for 55 bucks. I hope that does the job for me. I would appreciate the explanation about how to check the different angles. 45 and also 90 to the fence and what ever else you think that I might need to know. I check for the 45 but probably not like you do. Please help me. As I said I don't have to do to many miters but as of lately I have ran into a couple that has flat fooled me. The miter gauge that I purchased today is lazer cut and most anything that you get from Incra is top of the line.

   Once again, thank you for your time.

   Ralph

1. 
   forestgirl | May 17, 2003 06:37pm | #20

   Hi Ralph, I just took a look at the V27 -- it's a new product from Incra, and features the same head as the 1000 but with no extruded aluminum fence.  It is an excellent piece of equipment (I love mine, can you tell?).

   First of all, chances are you're going to need to make a fence to attach to it, and for miters I'd make one that extends past the saw blade so that you can cut a zero-clearance slot in it.  That way, when you cut your miters, the cut in the stock is backed up on both sides by the fence and will not splinter as you leave the cut.  Your fence needs to be flat and perfectly square to the saw table.  Face it with sandpaper up to the point of the saw kerf.

   I've been trying to find an illustrated article for you to reference for the tune-up cuts, but no luck so far.  It's a little hard to just describe them, but here goes:

   Assuming for the time being that you saw blade is a perfect 90* to the table and parallel to the miter slot, you need to first test your Incra gauge to make sure it is a perfect 90* to the blade.  Lay a piece of stock, say 1/2" thick x 2" or more wide, face down on the table and cross-cut it.  Lay the 2 pieces side-by-side just as they came off the blade, and then roll one over to the "backside" and push the ends together (like you're trying to re-assemble them, keeping the wood in a straight line).  There should be a perfect match-up with no gap between them.  Any gap you see is twice the size of your error in set-up.

   OK, once you get that set you can go to the 45* setting and test for that.  Get several pieces of stock lined up that are the same size.  I use at least 3/4" thick by 1.5" or wider.  Cut a 45* in a piece of stock, leaving 2 pieces at least 8 or 9" long each.  Flip one of the pieces over so that you can match it up with the first piece to form a 90* angle.  Mush them up together and check for 90* and look for any gaps (look at both sides!).  See this article, page 2. 

   If you need to check the saw blade for squareness to the table, you perform a test like the first one above (miter gauge at 90*), but instead of having the wood face down on the table, you put the edge of the stock down, presenting a tall face to the blade.  Roll one piece over and "re-assemble" -- again any gap is equal to twice the saw blade's deviation from 90* to the table.

   You might benefit from a good tablesaw book, as the illustrations are very helpful.  I'll go out to the shop and check mine (Kelly Mehler, I think) and see if it has all these tests.  Others Knotheads will have suggestions too, I'm sure.

   I'm off and away for a rare weekend away from home, but will check in tonight.  Good luck!

   forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl   ;-)

   Edited 5/17/2003 11:38:33 AM ET by forestgirl

   Edited 5/17/2003 11:39:56 AM ET by forestgirl

4. 
   RW | May 16, 2003 04:33am | #5

   for little things (base, crown, not carcasses) http://www.collinstool.com, check out the spring clamps.

   Your disk sander thing throws me. Cut correctly, sanding shouldn't be needed. Another thing for smaller work would be a miter trimmer. Think guillotine that goes sideways. Pictureframers use them, and I see variations thereof in cabinet shops from time to time. But those are costly; I'd expect about 3 bills for a good quality version on the low side.

   "The child is grown / The dream is gone / And I have become / Comfortably numb "      lyrics by Roger Waters

5. 
   migraine | May 16, 2003 04:38am | #6

   It doesn't make any difference on how perfect the joint is if the parts are not the exact lenght needed.  Also, try to buy one of those adjustable drafting triangle that are sold at a drafting supply house or a good office supply store.  Stick with "Stadler" or another German company.