Hi!
Ive been “lurking” for a while and reading allot.
I decided to make a torsion table to get my confidence up a bit. I am trying to Rip Full Size 2/4 MDF in a full length strip 3″ wide. I have wife and son and daughter units as needed to help. But I thought I would go with using an additional sheet of MFD and a Guide/Straight Edge and run my CS along it, Clamped in place?
The results are crap! Of my as much as a 32.. ( would not buy lumber this rippled), I am doing the best I can see keeping the saw against the Guide I set and cut two that are horrible. So before I wast any other MFD I am hoping the gods here have some better ideas.
I am hoping that there is a “better mouse trap” that I have not thought of… I was thinking of making a Guide for the CS some kind of a CS JIG? that will ride against the MDF guide truer?
Any help would be appreciated… I got an old Black and Decker CS. and am including a Pic of it and the Guide set up.
Thanks!
Rich
Edited 9/20/2008 5:12 pm ET by RichClark
Replies
It is a good idea to use a guide strip.
Some of the guides on the market are in two pieces. May not be straight plus they may flex a little. You didn't say what you are using for a guide.
A better idea, would be to rip a three or so inch wide strip off of your spare mdf sheet. Before you rip it mark the factory edge. After you rip it off. use the factory edge as the edge you run your CS against, the edge should be straighter than some guides and the three inch width should help it not to flex. The good thing is you can be as inaccurate with your strip cut as need be as long as you use the factory edge to guide with.
It is also good to set up a system to support those big sheets as you cut them. Some folks use a sheet of 2 inch idgid foam insulation and lay it on the garage floor the foam thickness will keep you from cutting into the floor, and the blade wont be hurt cutting thru the foam.
Another thing people sometimes overlook is that a CS is not a precision tool. Sometimes they lead a rough and tumble life. Make sure the edge of the base that u guide with is parallel to the blade use a combination squarre to check. Also if you saw is really old the bearings may have enough play in them to yeild a wavy cut. if you can wiggle the blade excessively back and forth perpendicular to its plane of cut you are probably getting a wavy cut.
If you are already guiding with mdf, then check the straightness of your guide edge. occasionally they are wavy from the factory.
Hope this helps.
Webby
Edited 9/20/2008 5:59 pm ET by webby
An infuriating problem that I have had happen when cutting sheet goods with a cs is for the plate of the cs to slip under whatever I am using as a guide. That is due to having only the far ends of the guilde clamped and then applying pressure against the cs/guide. The good thing is, if and when your torsion table is finished, you will have a better surface for cutting the sheet goods.
What I have tried with a little better success is to drive short screws into the guide to hold it steady.
Make sure you have a good ( fresh) blade.
More cutting problems arise from dull blades than any other factor.
Not sure what you mean when you say your cut is off by 1/32" or more. But I'll assume you mean you have a wavy cut. I've found that using a circular saw to get good cuts even with a guide requires a combination of hand placement on the saw, foot placement, posture, and a steady even stroke while making the cut. As others have mentioned a good blade is very important and so is a good saw. If the bearings are shot you'll get alot of runout which will result in a crummy cut. If you have the $$ and are serious about this hobby Festool is the way to go if you can't afford a tablesaw yet. The guide system and the smoothness of the saw make good cuts virtually goof proof.
If I had to do it with the means you have available I'd cut freehand with the circular saw, just eyeballing it about 1/8" past the line. Then use a long straight edge, preferably an aluminum or steel rule, and use a router with a straight bit to trim off the excess to get a perfect line. The router will leave a nice edge on MDF and cutting just a little (as opposed to going straight for the router) will give you almost no chatter or opposing forces to struggle against.
David Ring
http://www.touchwood.co.il/?id=1&lang=e
Thanks for the help.I have a Table Saw although not as wiz-bang as some. Its a 10" Ryobi T3000 with a Forester Woodworker II blade on it. I just have issues trying to wrestle the 4x8 sheet of MDF up on it to make that long of a run through it.I have a panel jig but not anything to run the long end through. I am making this Tension table 7x3'. It will be easy to set up a to cut the 3' slats and smaller crosspieces. I just thought it would be easier to cut the really long sides with a CS and guide but I think I am having the run out issue that was mentioned by "webby" that saw is a old friend but I never use it for this kind of work and It may just be to worn out.Once I get the shop squared away I will have proper extensions feeding and coming off the TS but right now I am trying to make a stable platform to make the rest of the stuff on.I do have some "rollered" run out's that I can use to support the sheet into and out of the TS and Ill set this up and give it a shot.Again thanks for the input, I appreciate it.Rich
If you have a Tsaw just cut the peices a little oversize then run them thru the tablesaw with your helpers to 'catch' for you. It is safer to do that than wrestling a big sheet.
The mdf I have bought is usually an inch bigger in each direction so you have a little material to sacrifice when cutting bigger.Webby
How many 3" pieces do you need?
If 3, cut off 9 3/4" and run the factory edge against your TS fence and repeat 2 more times.
Handling the narrow 8 foot strip should be no problem.
Remember to feed with slight diagonal pressure towards the fence.
The grid is cut and completed. I also attached the bottom and flush trimmed it.Using pieces of a lot of answers I did the following.Used a "factory" edge on another piece of MFD and "trimmed" (the one I tried to use and ruined) with a flush trim bit and my router.
Then I riped it freehand with my CS with the dimensions x2 with an 1/2 inch of slop (for the run out problem) and then ran the long piece through the TS and made two perfect (8'x 3 inch) sides for the table! I then measured and ruff cut 2 (3'x 16 inch) for the 10 (3' x 3 inch) width pieces and (one 3'x 22 inch) for 7 more(3'x3")that I cut into 4ths to be the interior spacers(27 total + a spare)The cool thing was that I just re squared the long 3" piece factory-edged to another after each rough cut and then I was done in no time.I want to THANK EVERYONE again for all the advise! I feel I have
acquired a new way of looking at accuracy with this tip and feel a lot more confident in what I am doing (instead of anguishing over how to do this).The bottom was added late yesterday also and nailed up. I used the factory edges of the MDF to square it and over cut the other 2 sides
and trimmed them with the flush bit as well.. It looks sweet!Rich
Edited 9/22/2008 11:04 am ET by RichClark
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