i have an Oshlun dado blade SDS 0842 – 8″, 42 teeth stacked dado – and am having a tough time getting a flat bottom. The right side of the dado is slightly deeper than the left side – I m trying to make box joints and the uneven bottom bottom is driving me crazy- is there anyway to adjust this ?
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Replies
How wide is the dado you are cutting, and is the difference caused by one or more cutters? What is the difference in the depth of cut? Big? Small?
Try rearranging the cutters by rotating them on the saw arbor. If this doesn't work, take the entire dado set to a sharpener; he may be able to grind all of the teeth so they cut to the same exact depth.
kreuzie
It is brand new - first time use! THe dado is 11/16 wide and the blade is square to the table. I will rotating the position of the chippers and see what happens.
Thanks all for your thoughts
If you are using the dado on a table saw check the alignment of your blade for square to the table if your blade is out of square one side will cut deeper than the other.If you are square its a sharpening problem as already posted.
regards from Melbourne Australia
If you take the dado set in , tell them about the uneven cut and ask them if jointing the set will help before sharpening .Sometimes dull blades can leave less than perfect results also.
dusty
"I m trying to make box joints and the uneven bottom bottom is driving me crazy...." Even if you fix the bottom of the cut, you may still end up with "bat ears" in the corners (I say may, because I didn't find info about the exact configuration of the blades). The Freud Box Joint Cutter set <click> will give you truly flat and non-eared cuts, if you feel like buying another toy....tool. I've used mine for both box joints and cross-grain grooves, it does a sweeeet job.
I agree with Forest.. Maybe something with the TS blade Zero (90) if all the same. Just a guess.
NO bat ears with the Oshlun dado set. Flat as flat can be, Just like the Freud box joint set.Work Safe, Count to 10 when your done for the day !!
Bruce S.
Cool.forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-)
How much "slop" is there in the arbor holes? A 5/8" arbor has a nominal design diameter of 5/8" and a manufacturing tolerance of +/- a few thousandths. The blades and chippers of your dado set have a nominal design diameter slightly larger than 5/8" and also have a manufacturing tolerance.
If your arbor happens to be slightly undersized (on the minus side of the spec) and some (or all) of the dado diameters are on the plus side, there can be enough "slop" to make dead-flat bottoms difficult to get.
I never measured my arbor or my dado blades, but here's what I've noticed.
Forrest 8" dado set. When used on the cheapo 10-yr old Craftsman TS, leaves the dado bottoms as rough as corderoy pants. When same set is used on the cheapo 35+ yr old Craftsman RAS, the dado bottoms are smooth as one could wish.
Bottom line: the dado set is fine, but S&R has slipped a bit in their tool quality over the last 30 yrs or so. ;-)
Mike HennessyPittsburgh, PA
I have no idea what kind of saw the OP has, but my post would be relevent to any brand. All manufacturing involves nominal dimensions with allowable tolerances. Craftsman may (or may not) have somewhat larger tolerances - I really don't know.You mention your experience with a Forrest dado set and Craftsman saws, then take a shot at Craftsman. How does that help the OP?
WHat do you mean by OP?
My saw is a Dewalt table saw - I know the dado blades fit the arbor pretty snug - snug enough that I cannot slide the dado off as a unit I have to remove blade/chippers one at a time.
You are the OP. It stands for Original Poster.
Good luck, GeorgeYou don't stop laughing because you grow old. You grow old because you stop laughing. - Michael Pritchard<!----><!----><!---->
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OP means "Original Poster". My last post was a response to MikeHennessy who seemed more interested in dumping on Craftsman than offering solutions to your problem.That's a pet peeve of mine. It's fairly common here for people to respond to a question by dumping on the OP's tool choices. FWIW (For What It's Worth), I use a Systi-Matic stacked dado set on a 70's era Craftsman table saw and have to stack and unstack my setups one piece at a time too. - lol
That's a pet peeve of mine. It's fairly common here for people to respond to a question by dumping on the OP's tool choices.
OK so we are Humans! I will leave it at that. Except most in here give an opinion based on what THEY do every day. I'd bet NO hate to you as given back to us!
I to didn't see it as trying to dump on someones tools. The Craftsman/Ridgid situation is a known problem but not necessarily known by everyone including everyone at Sears or Ridgid.I have been through this problem with a 1997 Craftsman top of the line contractors saw costing $900 I now have my Dad's 1957 40 year old Craftsman contractor saw used all these years in a cabinet shop gee guess what the arbor is the same size 5/8" diameter for the full length from the flange to the end of the shaft just exactly what the 1997 saw was not. Ridgid came out with a fix for this problem a new shaft. When I talked to Sears they sent me a replacement shaft with the same problem & tried to tell me that there wasn't anything wrong with it. I returned the shaft & gave the saw away just to get rid of it.I had the saw about 9 years & then I purchased a 1940 Unisaw for $200 & reconditioned it total cost for purchase & reconditioning $900.I now have a real good 69 year old saw I later received my Dad's saw which will go with this saw when I move into a bigger shop.I also have my Dad's 6" & 8" stacked HSS dado sets & on the Unisaw the 8" will cut a flat dado & both sets will cut flat dado's on Dad's old Craftsman. I cannot speak for the OP saw or dado set but it doesn't hurt to let this problem be known from time to time so if someone is looking for a contractors saw they will know what to look for. Because there are good Craftsman Contractors saws out there.Edited 2/8/2009 12:40 am ET by Originalbart
Edited 2/8/2009 12:41 am ET by Originalbart
I have a mid-1990's vintage Craftsman TS which performs quite well in every respect save one -- whatever chipper is next to the inside blade is quite likely to be off-center from the rest of the stack. I'm using the Freud dado set which normally make nice smooth cuts.Turns out that the problem is one in the original manufacture of the arbor. Just at the base of the threads, just to the right of where the arbor usually mounts the blade, there is an undersized gap. As a reformed machinist it looks to me like a manufacturing or design error. Whatever the cause, the result is that a regular blade mounts fine, but anything mounted in the next 1/100 of an inch or so has the wobbles. It probably passed muster because whoever made decisions about what goes out the door forgot about dado sets.Anyway I have been able to work around by shoving in a handful of shims to get past the undersized part of the shaft. I then bury the right side of the stack in a sacrificial fence to get the width I want. Anything not at the end of the piece undergoes trial by router.Yeah, I'm keeping the Craftsman, but I haven't bought from Sears for several years.
Turns out that the problem is one in the original manufacture of the arbor. Just at the base of the threads, just to the right of where the arbor usually mounts the blade, there is an undersized gap.
I could be wrong but I 'think' the original RIDGID saw had the same problem.. I have a RIDGID (works for me) but never use a Dado blade on it.
Actually I did not see it as dumping on the brand, more as an observation that things have changed over the years. Could be useful info to the OP.
................................................
Men will never be free until the last king is strangled with the entrails of the last priest.~ Denis Diderot
Your reading, sir, is a bit more insightful than my writing! ;-)
I was not dumping on Craftsman -- I have two Craftsman saws that I use regularly and, if they were junk, I'd junk 'em! Fact is, they suit my purposes just fine. I was simply pointing out the difference in the performance of one dado set on two different machines, of similar type/price point, but manufactured in different decades, with the newer machine suffering from looser tolerances than the older. The usefulness to the OP is that it demonstrates that, IME, the problem is probably with the arbor, not the blade.
OP may have different machines (probably does -- he didn't say he had a Craftsman, tho' you seem to assume he does since you say I dumped on his choice of tools) and does have a different blade. But the theory still applies.
I did not offer any solution for an arbor that's undersized 'cause I don't know of any, short of upgrading to a saw somewhat higher on the quality spectrum. As for me, if I want smooth-bottomed box joints, I need to clean 'em up by hand (there I go again, extolling hand tools and dumping on power tools. DOH!), or choose a different joint since my tooling, apparently like the OP's, simply isn't up to the task of perfect box joints. Not a "dump", just a recognition of the reality that my $700 saw should not be, and is not, expected to perform as accurately as a $2-5,000 saw. They don't charge those extra bucks just for the paint color, after all. ;-)
Mike HennessyPittsburgh, PA
Personal experience here: My 8" Forrest Dado King works equally well with flat bottom box joints on my old '85 model CraftsmanTS and new '08 Grizzly TS. This may be a satement of the obvious, so I hope that no one takes offense, but are your cutters on the right sides of the stack?
I double checked the cutters and they were right. I also rearranged the chippers - out of 4 "1/8' chippers apparently two are longer than the others - I get deeper cuts where I moved them to.
Any chance of sending it back, or contacting Oshlun about the discrepancy? Even at a bargain price, it's not right to be selling defective sets unless it's disclosed in advance.
Interesting experiences - I assumed, with few exceptions, that saw arbors and dado blades would be pretty consistent. I appreciate the thoughts. I will repost what I learn - thank you all
Edited 2/6/2009 6:00 am ET by kre8ted
I gave up on the finger joints and used a through dovetail jig. The dovetails came out very nicely - I appreciate everyone's posts. Now a new problem with the same project:
I am making a toy box and want to put my grandson's name on it. Can anyone give me some tips on inlaid letters? The toy box is made out of ash, 34*20*20 with through dovetails. I want the lettering to fit the style but while the through dovetails look really good I am struggling with the style of lettering to use for his name and how to do the inlays.
For the lettering, use your computer and look at the different fonts to spell out his name. I have used this in the past and it can give good results.
I have been playing around with the fonts so that can work. Do you have any ideas on making templates, do you just do the inlay by hand or do you recommend no inlay?
I've only done this once before, so take it for what it's worth:
Print the text or other artwork on a piece of paper.
Attach the paper in position on the wood with spray adhesive or rubber cement.
Knife through the paper into the wood to mark the outlines.
Remove the pattern, and then carve out the waste with chisels, gouges, etc. Remember that it's the sides of the cavities that matter; the bottoms don't have to be perfect. Just ensure that they're all 1/16" deep or thereabouts.
Make more copies of the pattern and attach them to your inlay wood. Start with stock that's about 1/8" thick.
Cut the inlay pieces a little oversize, then trim to fit. It pays to be picky here; if you screw up a piece by cutting it too small, it's easy to start over on a new one. Cutting a slight bevel edge on the inlay pieces helps ensure a tight fit.
Glue the inlays in with epoxy or other gap-filling adhesive. Clamp them in place by putting another board on top (with some waxed paper in between!) and weighing the sandwich down with bricks or whatever.
Plane, scrape and/or sand flush.
Most importantly, practice on scrap first; don't use your real project for education.
-Steve
As someone else mentioned if you have slop on the arbor that could be an issue. If not, my brother took his set to a machine shop and had them match ground. Myself, I have a set but whip out the router mostly now.
If it moves, tax it. If it keeps moving, regulate it.
And if it stops moving, subsidize it.
What is the manufacturer of your saw? Craftsman and early Ridgid tablesaws have a type of arbor that prevents a dado from cutting a flat bottom.
I don't think I'm helping, but I got the Freud Dado and it cut flawlessly. The bottom is perfectly square. I just install and use it, not adjustment needed. I also have other brand dadoes, but I only found Freud work best.
Q
Note that most stacked dado sets use an alternating top bevevl grind (ATB) on the outside cutters (that grind reduces tearout). Any set that has an ATB grind will leave minor grooves at the outer edge of the cut (aka "bat ears")....it's often very minor, but none are truly flat that use the grind. To minimize the effect of the bat ears, some sets include a flat raker that is slightly shorter than the tops of the ATB teeth, but bat ears still exist to some degree. Only a flat top grind (FTG) will leave a perfectly flat bottom, but will also typically have more tearout in ply, melamine, crosscutting hardwoods, etc.
What you describe sounds like more of a problem than most bat ears pose. How solid is your throat insert? If it's flexing, it could definitely cause problems with the cut. I also assume the workpiece has a flat face? I'll second the suggestion to rearrange some of the chippers to see if you can isolate the problem to a single chipper. If the problem stays regardless of the chipper arrangement, then the problem is likely something other than the dado set.
Edited 2/6/2009 2:23 pm ET by Knotscott
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