perfectly accurate mitres
- Thread starter jimbob
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giday [welcome] to the fog
miters on picture frames are tricky.
the trick is cut oposing sides together so that they match perfectly.
the saw doent need to cut a perfect 45% angle a 0.1/0.2 either way wont matter if you cut one set on one side and the other set on the other side of the blade. any misallighnmet on the angle will be allowed for in the other side.
i have seen sleds for the table saw for cutting miters that work like this.
you could use an mft with qwas dogs
miters on picture frames are tricky.
the trick is cut oposing sides together so that they match perfectly.
the saw doent need to cut a perfect 45% angle a 0.1/0.2 either way wont matter if you cut one set on one side and the other set on the other side of the blade. any misallighnmet on the angle will be allowed for in the other side.
i have seen sleds for the table saw for cutting miters that work like this.
you could use an mft with qwas dogs
mouppe
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This is the method that I have found to be the most reliable.
Take a piece of plywood or MDF about two feet square. Glue and screw a block to it about one inch high running along the length of one side of the plywood or MDF. The inner edge of the block must be a straight edge. Using a square, screw a second block in place at 90 degrees to the first block on another edge of the plywood. The two blocks should be almost touching but leave a small gap. Do not screw it in fully until you are sure it is aligned at exactly 90 degrees. I screw it in sufficiently to hold it in place and then tap it with a hammer to get it exactly right. Then screw it down firmly.
Now you have a 90 degree jig. Clamp it to the MFT so that the cut will be roughly 45 degrees each side. If you are out by a few degrees either way it will not matter as long as the two angles sum up to 90.
Hold one picture frame side tight to one of the blocks and make the cut. Repeat with the second side against the second block.
If you find one side is too long, you can easily trim it with this jig and the angle will remain the same. Just be careful not to run the saw all the way through the plywood base.
Take a piece of plywood or MDF about two feet square. Glue and screw a block to it about one inch high running along the length of one side of the plywood or MDF. The inner edge of the block must be a straight edge. Using a square, screw a second block in place at 90 degrees to the first block on another edge of the plywood. The two blocks should be almost touching but leave a small gap. Do not screw it in fully until you are sure it is aligned at exactly 90 degrees. I screw it in sufficiently to hold it in place and then tap it with a hammer to get it exactly right. Then screw it down firmly.
Now you have a 90 degree jig. Clamp it to the MFT so that the cut will be roughly 45 degrees each side. If you are out by a few degrees either way it will not matter as long as the two angles sum up to 90.
Hold one picture frame side tight to one of the blocks and make the cut. Repeat with the second side against the second block.
If you find one side is too long, you can easily trim it with this jig and the angle will remain the same. Just be careful not to run the saw all the way through the plywood base.
I have lots of experience here, all gained the hard way. Not only do the angles need to be correct, but more importantly the opposing sides must have lengths that are identical. I have had excellent results on the table saw after I purchased the Dubby left and right side sliding tables with stops for the length adjustments. Practice on scrap to get everything right. This system will not let you down.
I have the Lion (or is it Lyon) trimmer with a guillotine type of knife. This is useless as a "saw", but is extremely handy as a "planer" or "shaver" to do some fine tuning.
I have the Lion (or is it Lyon) trimmer with a guillotine type of knife. This is useless as a "saw", but is extremely handy as a "planer" or "shaver" to do some fine tuning.
I messed up the url insertion http://www.in-lineindustries.com/RDMuller said:
fidelfs
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Learn to shoot with a hand plane, you will never see tight miters than ones made with shooting.
Use the Kapex and leave them 1/16 or less bigger and shoot them with a hand plane.
See how they made themin this picture frame video
Creating a perfect mitered joint with a shooting board
Use the Kapex and leave them 1/16 or less bigger and shoot them with a hand plane.
See how they made themin this picture frame video
Creating a perfect mitered joint with a shooting board
Michael Kellough
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Stock miter saws are good enough for stuff you put up on the ceiling or down on the floor but for perfect miters that are going to be closely scrutinized you need something special.
As Richard and Allen say if you are going to use on one general purpose saw you need to make a jig that will allow you to cut the parts while they are in the relationship they will be in when assembled.
The jig Richard describes can be modified to fit on a miter saw or if you add runners it can slide on a table saw.
Also as mentioned guillotine trimmers are used for final trimming of saw cut miters. The precision of the guillotine is jig enough that you can use a stock miter saw for the initial cut. Following along from the shearing knife idea you go back to the original way of trimming miters, using a hand plane on a shooting board with dog ear for miters.
This is the best set I know of, read about it here.If interested you can buy it here. You might not need the accessory donkey ear for shooting simple miters. Depends on how large the cross section of the frame stock is.
While I was typing this some more replies came in, sorry for the redundancy.
As Richard and Allen say if you are going to use on one general purpose saw you need to make a jig that will allow you to cut the parts while they are in the relationship they will be in when assembled.
The jig Richard describes can be modified to fit on a miter saw or if you add runners it can slide on a table saw.
Also as mentioned guillotine trimmers are used for final trimming of saw cut miters. The precision of the guillotine is jig enough that you can use a stock miter saw for the initial cut. Following along from the shearing knife idea you go back to the original way of trimming miters, using a hand plane on a shooting board with dog ear for miters.
This is the best set I know of, read about it here.If interested you can buy it here. You might not need the accessory donkey ear for shooting simple miters. Depends on how large the cross section of the frame stock is.
While I was typing this some more replies came in, sorry for the redundancy.
mouppe
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I have a mitred shooting board, but I have found it to be less accurate than the jig I described (when I use it, not speaking in general terms).
The fence on a shooting board needs to be exactly 45 degrees, and sometimes the wood moves or the fence is slightly off etc. If the reference sides of the picture frame are not straight, you will not get a good result.
With the jig, you only need to ensure that the two blocks are square to each other, even if one cut is not 45. One could be 50 and the other 40 for example.
I made four of the jigs and use them as clamping blocks when I glue up. I also stick a domino in each corner to help with the horizontal alignment and to provide long grain glue surface.
The fence on a shooting board needs to be exactly 45 degrees, and sometimes the wood moves or the fence is slightly off etc. If the reference sides of the picture frame are not straight, you will not get a good result.
With the jig, you only need to ensure that the two blocks are square to each other, even if one cut is not 45. One could be 50 and the other 40 for example.
I made four of the jigs and use them as clamping blocks when I glue up. I also stick a domino in each corner to help with the horizontal alignment and to provide long grain glue surface.
Michael Kellough
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Richard, I use a jig that slides on the table saw, similar to the one you described. Works very well.
junk731
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Table sawn miters from Fine Woodworking.
http://www.finewoodworking.com/SkillsAndTechniques/SkillsAndTechniquesArticle.aspx?id=5188
John
http://www.finewoodworking.com/SkillsAndTechniques/SkillsAndTechniquesArticle.aspx?id=5188
John
pugilato
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I modified a jig I saw in FWW for the MFT3, install it using Quas dogs and clamps, and cut the 45's with the TS55 and a miter saw. The nice thing about the jig is that it lets you cut each opposing side to the same exact length without having to measure the actual framing material. I am including photos of the jig (it needs to be improved, and will not work on sides
Richard Leon said:
A jig like Richard describes for the MFT or the table saw jig that Michael uses are probably the cheapest way to get dead accuracy on picture frames. EDIT: Dead accuracy doesn't mean exactly 45 degrees each half -- one side could be ~44 and the other side ~46 but a perfect fit when joined.
I have Tico's excellent shooting board that I use often but there is a problem when doing picture frame material that doesn't lend itself to laying on it's back to shoot the mating 45.
If you do a lot of frames the Lion trimmers are hard to beat however I understand the quality of the Lion trimmer has fallen off: http://www.lionmitertrimmer.com/demo.htm Old ones do turn up on e-bay occasionally. Lee Valley also sells one: http://www.leevalley.com/US/wood/page.aspx?cat=1,42884&p=32922
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