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how to cleanly trim 1/8" off of a panel edge ???
I just cut two baffle blanks out of 3/4" thick MDF. Due to an error of about +/- 1/16", one is now 1/8" different than the other. The anal retentive part of me wants to make both the same width without losing much material. I would just pass it thru my table saw but 1/8" is just about the blade kerf so that is a no go. Because my fence can only open to about 20.5" and these need to be cut to about 23" wide I cannot do it from the "other" side. Perhaps I should just trim off 1/4" and 1/4"+1/8" from the two pieces, thus making them the same width but sacrificing 1/4". This might just result in two new widths that are again not the same. That's the sort of carpenter skills I possess...
OTOH am I thinking of the wrong tool for the job here? Should I just accept the flaw and move on? Panels will never be right next to each other...
Anyway this has come up before and I always wondered what the best approach to solving this problem would be. So please chime in with your creative ideas.
Comments
Stick your two boards together with carpet tape, use router trim bit and trim the one panel down to match the other. Just like cutting any template, the smaller baffle is the template.
For baffles I usually leave the baffle dimension slightly large from the get-go, then trim the baffle to the cabinet edge once the cabinet is complete. That way the baffle is always sized to the exact cabinet shape without having to worry about a cabinet that is slightly out of square or 1mm off the intended size.
I often cut panels large and trim them down with the router flush bit after glueup. However, if this is one of the panels that has another panel glued on top of the end then they do need to be exact size to begin with.
I like the above router idea better... but a clamped straight edge and circular saw could work too
I do as mentioned above or use a straight edge clamped down and then use router….
That's a great idea. I do have a flush trim bit. The panel thickness (3/4") should be enough for me to support the bearing on the lower panel while the upper one is being trimmed away. Once the wildfire smoke clears out and I can go outside again I will give it a try.
Just to be clear, this is a flat panel for an OB speaker baffle. There are no "sides" to flush trim to, and there is no cabinet.
Charlie no one would ever notice a 1/8 of an inch difference in baffle width
You are probably right. It might be noticeable when the baffles are placed into the rest of the loudspeaker due to some tight clearances, so I would like to even them up just in case.
If you have a 1/8" rabbit bit and a flush trim bit, you can make a pass with the rabbit bit removing 1/8" as deep as possible and then come back and finish the leftover with the flush trim.
As Decibel said, except I use the thicker 3M double sided tape. It'll give you a bit of space to get a putty knife in to pry the panels apart. Also you don't need much tape, with the 3/4" wide tape, four pieces an inch long spaced in a bit from each corner will be fine.
Trick for removal of the tape is to use your thumb to press and roll the tape off the board rather than trying to peel it off.
Agreed, provided quality double sided tape is used - less is better. Ask me how I know
For double sided tape I use the window insulation tape that is used on the film insulation kits. I find it on sale cheap in the spring.
PSA about PSA (pressure sensitive adhesive) apply more force for better adhesion. I often clap the tape together before routing.
I have some VERY sticky double sided carpet tape that will actually damage MDF. I put blue painters tape on both boards and use the carpet tape on the masking tape. Holds tight but removes easily
No need for extreme pressure with the 3M stuff. This can make removal more difficult. Also test on a scrap piece of wood as some tapes will pull the wood fibers up.
OK, the job is done now. Thanks for all the suggestions.