Replies

1. 
   sawdustmaker | Apr 09, 2004 04:35am | #1

   Bob

   I cut most of my 45s on a jig for the table saw. There are many plans available in magazines. If you build one that allows you to cut on both "sides" of the jig, and you cut each joining leg on opposite sides, they will almost always fit perfectly.

1. 
   bobblack | Apr 10, 2004 02:18pm | #7

   thanks for the info, I tried cutting on opposite sides of the blade and it came a little closer but not quite as close as I would like. At least I now know part of the problem is with my blade alignment. I have a trademaster tablesaw and I tried all day to figure out how to align the blade, but the sucker will not move. Guess it's time to bite the bullet and purchase another one. By the way, what would you call the jig you recommended so I can look one up   thankyou and all the other great guys that answered my post, sincerely, bob black.

   p.s. I have two seperate plans for the barrister bookcase and they both indicate installing a spline.so now I'm not sure what to do. Could you comment on that please.

1. 
   BG | Apr 10, 2004 03:56pm | #8

   Bob,

   Please accept the following as my opinion...I could be dead wrong.  Primarily a spline is to provide additional strength and sometimes help with alignment.  Usually a well designed plan will not include unnecessary joinery techniques, however, it's hard for me to imagine that the post of a barrister bookcase where long grain is being glued to long grain would need such additional strength.....I think of the spline more necessary with end grain glue ups such as in boxes with 45's. 

   Cutting  those splines perfectly is another issue.  The best jig I have seen is a ramp at a 45 degree angle to the TS table and 90 degrees to the fense...with a runner that fits into the TS snugly....you may want to make the ramp/runner adjustable so you can slide the ramp in and out....the blade is straight up(90 degrees) when cutting.

2. 
   TomMGTC | Apr 09, 2004 04:45am | #2

   You can probably close up the gap with a burnisher or the shank of a screwdriver. The gap will disapear and the corner will be a little more durable since the edge will be ever so slightly eased. If you want you could also hit it with a steam iron over a towel prior to burnishing. A paper wide gap isn't much. It should close up nicely. 

   Tom

   Douglasville, GA

3. 
   BG | Apr 09, 2004 02:12pm | #3

   bob,

   Recently I completed a project where a higher degree of accuracy was required and came up (from research) with a couple of tricks to consider.  First, with a rip cut 45 like your working with I would not be surprised if the wood moved a bit between cutting and gluing...so it may not be your fault per se.  Second, I read you could take a block plane and take a few passes on the inside of the 45 to tighten up the outside edge a bit.  Third, from Woodworks mag, use a few dots of super glue on the edge of the miter, in addition to the regular glue, and hold the joint together to get a better outcome.  Of course, Tom's idea is great and perhaps the best workaround... 
4. 
   Fingrs | Apr 09, 2004 03:15pm | #4

   I'll show my age and confess that when I saw the title of your post I thought you were referring to records...you know, 45 RPM records. 

   The way I cut 45's, depending on the tool being used is to cut opposing pieces (the ones that make up the miter) on opposite sides of the blade.  This works for a miter saw or radial arm saw, and can be done with the table saw but not quite so easily.

   Assuming your saw table is flat and the fence straight, cutting on either side of the blade when it's set to 45 degrees will give a pretty good 90 degree match, and will compensate if the blade is not vertical.  A sled on the table saw works best, but my method is quick and if it gives you good results, great. 

5. 
   mike4244 | Apr 10, 2004 07:08am | #5

   Bob,your saw has to be in perfect alignment, blade to fence, trunnion at 45*. The stock has to be flat and straight.That being said it helps to have ajointer to clean up the saw cut. The jointer fence also has to be exactly 45*.

   Have you glued up the posts? If not do as another post said and plane the inside of each miter slightly. You may have to thin the splines so they fit loose. Could be the spline is the problem not the cut. Next time dispense with splines, there not needed  with long grain glueups, and many times they hinder rather than help alignment.When planing do not plane the edge of the miter, you just want to relieve the back so you wind up at 90*.

   mike

6. 
   sawdustmaker | Apr 10, 2004 01:21pm | #6

   You can take BG's comment about the plane one step farther with a "shooting board" that lets you hold the piece on a true 45 while "shaving" off the end with a hand plane. I have not used one, but it's on my list of things to build in the shop, along with about three dozen things my wife has asked for over the years.

7. 
   RMillard | Apr 12, 2004 03:42am | #9

   Bob Black,

   I don’t rip my miters on a table saw, but instead on a bandsaw ( I dislike the table saw), but even on a well tuned table saw, I doubt they’d fit together perfectly without a bit of planing.I don't have much faith in jointers ( the power kind) to effect a tight joint, so I'd use a longish hand plane to achieve a proper fit. While I have a Stanley 386 guide, I plane the edges most often by eye. My goal it to get them to fit without any gaps that can’t be closed with slight hand pressure ( it sounds like you are already there) . I find clamping to be the real hurdle. To overcome this obstacle I either glue or clamp a strip of wood to the outside face, parallel to the mitered edge of the pieces to be joined together. These will provide a surface for clamps to have a "purchase" as they are placed across the joint, to pull it tight.. A little experimentation will give the proper set back from the mitered edge, where to place these strips, in order to provide the best clamping action. I normally don’t ever advocate biscuits ( I leave that to Norm, along with making real money at woodworking), but they help to keep joint aligned as it is clamped.

   Rob Millard

1. 
   eddiefromaustralia | Apr 12, 2004 04:19am | #10

   Bob,

   I normally shoot mitres to fit - freehand in the vice, using a tablesawn mitre as the starting point.

   You'll need a sharp plane and that's it.

   I agree with the comments about splines/biscuits - they will help with alignment.

   Rob,

   A trick for clamping mitres that we were taught in third year of training.

   Cut apart old upholstery springs with an angle grinder, leaving a spring of approx 340 degrees round.  Sharpen up both ends to a point.  To clamp a mitre, simply open the spring under hand pressure, locate the points of the end of the spring so that spring pressure is across the joint where you want it and then slowly let the spring onto the wood.

   Instant mitre clamps.

   Hope that this makes sense - Festool (Felder?) sell a professional set of these but they cost about USD140- more than scrap springs and about 10 minutes of your time.

   I'll have a quick look see on the internet to see if there's a pictured article/diagramme, if not, I'll post anyway. 

   If what i've said doesn't make sense here, let me know & I'll sketch up a quick diagramme of what I'm saying.

   Cheers,

   eddie

1. 
   Biscardi | Apr 12, 2004 04:35am | #11

   Folks,

   I just had a catastophic failure of a project I made 5 years ago. There were some design  and wood movement problems. The piece also got good and wet several times when the roof at the church leaked- not to make excuses.

   The biggest problem in the piece was that several mitred joints came apart. It is all end grain. Even glue blocked, they wont take much force to fail.

   It is unfortunate that mitred joibts look so good and hold up so poorly.

   Frank

1. 
   ian | Apr 12, 2004 05:19am | #12

   Frank

   you could always use a dovetail key to hold the joint closed, or if real lazy V-nails as used by framers.

   Ian

1. 
   EdHarrison | Apr 13, 2004 03:49pm | #13

   I made some picture frames for my neighbor recently - I'm an amatuer but I did get paid for this, so I guess it was a commission - the front (facing) part of the joint was a 45 degree miter joint and the back part was a bridle joint. Made with a miter box and hand tools. They fit together perfectly, easy to clamp and get square, and plenty of glue surface with the bridle joint part of it. Used a sharp shoulder plane to trim.

   I'm at that point where everything I do with handtools is easier than I expected and everything with machines is harder. Been working with machines for 20 years and hand tools for about 3, so it's bass-ackwards from what you would expect. Maybe I have more of the spirit of discovery going with handtools.

   FWIW. Ed

2. 
   Biscardi | Apr 14, 2004 02:02am | #14

   Ian,

   I am afraid I don't understand. What is a dovetail key?

   Thanks,

   Frank

3. 
   ian | Apr 14, 2004 01:06pm | #16

   Frank

   imagine a bow-tie shaped piece of wood inserted in a matching rebate cut across the back of the joint.

   Ian

2. 
   bobblack | Apr 14, 2004 02:19am | #15

   excellent idea with the spring clamps Eddie. think I'll go to the local dump and see if I can find some  Could be a problem though, our dump has signs up (no picking) haha   bob

3. 
   eddiefromaustralia | Apr 21, 2004 08:56am | #17

   All,

   Came across this picture that shows the clamps in use

   <a href="http://forums.taunton.com/n/mb/View Image

   Cheers,

   eddie

2. 
   LeeEschen | Apr 23, 2004 08:07am | #21

   Please, please, please, don't post in tiny type. Even with my reading glasses on, this post (17265.10) was virtually unreadable. Just post in the default type. There is plenty of room to say anything that needs to be said without shrinking it down to miniscule.

   --

   Lee in Cave Junction, Oregon;

   Gateway to the Oregon Caves

8. 
   WayneL5 | Apr 22, 2004 03:20am | #18

   Another possibility.  Were your joints tight before you glued them?  Are the faces flat, or did they rock?

   Moisture from the glue can swell the wood slightly.  When the glue dries, the wood shrinks and can open a small gap.  A paper width gap is not unreasonable.  If the joints were tight when you clamped them, but didn't open up for a few days later this may be a possibility.

   You may also need to true up the cut face on a jointer.  You wanted another tool, didn't you?

   Another way to make the pieces, which uses more wood and requires a planer and jointer, is to glue your two pieces together flat in an oversize block.  They need to be 1½ times as wide as your finished piece.  After the glue is thoroughly set (a couple of days), cut your square block out of them at a 45° angle.  In other words, cut a diamond out of your oversized square, your diamond being a square of your finished size.  Cut them about 1/8" oversized and finish them on the jointer and planer.

   A nice thing about woodworking is that there are so many ways people solve problems.

1. 
   bobblack | Apr 23, 2004 01:36am | #19

   thanks waynl5, good info is always appreciated. I still haven/t glued them I am deciding if I am going to install the spline the plans call for, bob

9. 
   Steinmetz | Apr 23, 2004 02:37am | #20

   bob, Goggle up COLLINS CLAMPS  A special pair of pliers with spring clamps      Great tool  STEIN.