blade thickness gizmo

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A while back - 2-4 years? - someone posted about a commercial gizmo (made from aluminum) that was used to compensate for blade thickness when cutting half laps, grooves, etc. on a saw.
Basically, one set it to the thickness of the wood for which one was cutting a groove, made one cut, flipped the device and made the next cut, thus outlining the area. "Flipped" because that end had a way to adjust for blade thickness.
Anyone remember the name of the device? Cute little thing but kinda pricey, about $90 IIRC.
Thanks
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On 03/09/2015 10:36 AM, dadiOH wrote:

http://www.bridgecitytools.com/default/km-1-kerfmaker.html
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On 3/9/2015 12:36 PM, dadiOH wrote:

Had to walk out to the shop to check the name and Doug beat me to it.
My unifence fence doesn't seem to allow the kind of accuracy I was hoping to get with the tool because of the slight backlash when locking the fence.
Leon uses his more that I have, with apparently good results.
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Lawsy, so quick! :) Thanks, guys.
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On Monday, March 9, 2015 at 2:03:40 PM UTC-4, dadiOH wrote:

OK, guys, 'splain me sumthin...
Will this device help me with my kitchen door project?
The 1/4" grooves for the panels are cut. The next phase is to cut the stub tenons on the rails. The joints are offset such there will be a ~1/8" reveal on the back of the door and 3/8" on the front. The tenons will be 1/2" in length.
(Maybe I should have cut the tenons first, and then matched the groove to them, but it's too late for that now.)
Will this device help me set up dado so that I will get a perfect tenon? Since I have to do the tenons with 2 separate set-ups due to the offset, frankly, I'm a tad nervous. If I get the first side wrong, I'm screwed.
A device (or a suggestion) for getting perfect offset tenons to fit pre-existing grooves would really help get me back on track.
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No, the kerf maker is only used to cut a grove or dado to the width of the piece it will receive. Bridge City does however also make a tenon maker. http://www.bridgecitytools.com/default/tm-1-tenonmaker-1.html
That said, I don't know it it will solve your issue. Have you tried drawing the set up to see what needs to be cut and where?
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On Monday, March 9, 2015 at 5:43:49 PM UTC-4, Leon wrote:


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No, I don't think that will help.

As I was typing up an explanation of what I thought my problem was, I think I came up with a solution. You know all of this already, but I'll spell it out so you'll know where my head was at.
Let's say I wanted to center my panel in the 3/4" frame. I'd cut a perfectl y centered groove, using the 2 pass, flip-the-board-end-to-end method. Then I'd cut my centered tenon on a rail, making it too big, then sneaking up o n the final thickness by taking a little off both sides until it fit snug i n the groove. Once the blade height was correct, I could cut 10,000 centere d tenons without changing the set-up and they would all fit perfectly.
However, since my groove is not centered (by design), I need 2 blade height s for the tenon: one for the 1/8" shoulder and one for the 3/8" shoulder. T heoretically, I should just be able to set the dado blade to 1/8", cut all 110 1/8" shoulders, then reset the dado to 3/8", flip the boards and cut th e 110 3/8" shoulders. As we all know, theory-created tenons always fit perf ectly, but practice-created tenons might not.
At first I couldn't think of a way to test the blade set ups because of the offset groove, then I came up with this:
If I turn a groove into a rabbet on a spare stile, I will remove the obstru ction and can then test one of the shoulders for a flush fit with the face of the frame. Once I have that height, I can cut that side of the 110 tenon s. Then I can sneak-up on the other side (the 1/8" shoulder) until it fits snug in the groove. Once I have that height, I can finish the 110 tenons an d they'll all be perfect. :-)
This picture explains what I mean. It's seems pretty simple now that I've t hought of it, and it's probably old hat to you guys, but to me, it's all br and new.
http://i440.photobucket.com/albums/qq121/DerbyDad03/OffsetTenon_zpsawdowuog .jpg
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Exactly. :--). Now all you/and I have to do is figure out a way to consistently cut all the tenon pieces to fit even when the rail has an ever so slight bow or a rail from another board that for some reason or another just happens to be 1/128" thicker or thinner than the rest. :-) Oh! One more hint. Always test the fit on the actual end of the stile where the rail will fit. IF you test fit in the groove in the middle of the stile the groove may not be the same width as at the ends. This is pretty common if your stiles are not perfectly flat when cutting a "centered" groove.
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On 3/10/2015 7:09 AM, Leon wrote:

When you paint yourself into this kind of corner, either use a router table and one of the many rail/stile/tenon cutting bits available, or expect to take forever getting the job done satisfactorily.
AKA why we learned to always center our panels when cutting _stub tenon_ doors on the table saw. :)
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On 3/10/2015 9:01 AM, Swingman wrote:

Cutting centered groves on the TS works well if the stock is all consistent in thickness and perfectly flat.
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On Tuesday, March 10, 2015 at 10:01:42 AM UTC-4, Swingman wrote:

ever

her


Yeah, but there is on more factor, something I mentioned in an earlier post related to this project:
When I built a prototype door with a centered panel, neither SWMBO nor I li ke the looked. My brother had his kitchen re-done and he has the offset pan els. We *really* liked that look and are trying to replicate it. We even we nt to the Borg to look at all the shaker style option and the offset panel consistently won.
I'll see what I can do on the TS and if I can't get it to work, I'll try th e router table route. I know it's more work and will take more time, but ti me I've got. :-)
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On 3/10/2015 9:46 AM, DerbyDad03 wrote:

Cutting a grove on the edge of rails and stiles off center is just a little more trouble than centered and so is cutting the stub tenons.
Instead of making a pass and flipping the board and making another pass for the groves you simply run all pieces through one time, adjust the fence, and run them through again in the same direction. Done. Use a scrap for set up.
The stub tenons are basically done the same way, cut one side on both ends first and on a scrap, adjust dado blade height and check on the scrap, then cut the opposite side of the rail on both sides. Done.
I can't see how there would be any advantage to using a straight bit on a router table vs. a dado blade on a TS unless using Rail and Stile router bits which tend to fit together regardless because there is no adjustment other than height location.
The big issue with both the TS and router table methods is if the wood is not exactly the same thickness or if the wood is not perfectly flat. It should be obvious why different thickness brings up an issue but if the wood is not flat it will cause tenons to be shallow on the bottom side if the wood bows up in the middle. If the wood is not dead flat against the work surface at the cutter the cut is going to be off.
You are looking for a perfect fit on these type joints, even being off 1/256" will result in a less than desirable fit. If the joints do not hold together with out glue they are probably too loose and if you have to use a hammer to close the joint they are too tight.
Also, as I have brought up in the past, the quality of your blades or cutters can affect your results. Yeah the cheaper dado blades and regular blades can get the job done. The better blades result in less tear out. Tear out can wrap around the end of a board and raise it causing a slight gap between the table surface and the face of the board. Even excess dust on the table surface or board surface can cause problems.
Now having said that these joints typically still work if a bit less than perfect. Mine are not all perfect for reasons I have listed and the relative moisture content of a board can throw off thickness enough to cause an inconsistency in board thickness. But add wood glue to a loose fit joint and the wood tends to swell and the fit becomes better.
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On Tuesday, March 10, 2015 at 11:28:51 AM UTC-4, Leon wrote:

n ever

other

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post related to this project:

I like the looked. My brother had his kitchen re-done and he has the offset panels. We *really* liked that look and are trying to replicate it. We eve n went to the Borg to look at all the shaker style option and the offset pa nel consistently won.

y the router table route. I know it's more work and will take more time, bu t time I've got. :-)


Actually, I was recently gifted an Amana dado set. With the set I was able to cut the 1/4" groove in a single pass. The groove fits the 1/4" MDF that I will be using perfectly. Note: the 1/4" MDF from HD is not 1/4" (7/32-ish ) The 1/4" MDF from the lumber yard where I bought the poplar is 1/4" and f its the dado set grooves perfectly.

I think the method described in this picture is the same as what you are sa ying in your text. As they used to say on my high school essay exams, pleas e compare and contrast.
http://i440.photobucket.com/albums/qq121/DerbyDad03/OffsetTenon_zpsawdowuog .jpg




I assume the Amana set is one of the "better blades".


That's my hope: Maybe not perfect, but tight enough to work and to last. Th e fact that they will be painted should allow for slightly less than perfec t to suffice from a visual perspective, anyway.
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DerbyDad03 wrote:

I know you are filled with angs tbut it will be easier than you think and all will work well. Face it: cabinet doors - (MOST cabinet doors) - aren't stressed beyond opening and closing. If the tongue goes in the groove without major rattling and if you use glue, they will hold together.
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On Tuesday, March 10, 2015 at 3:52:44 PM UTC-4, dadiOH wrote:

Thanks for the encouragement. I'll never know how this will turn out unless I actually put blade to wood and I also know that things rarely turn out as bad as we think they will.
Besides, this isn't rocket surgery. It's just wood and wood can be re-bought and re-cut if things go terribly bad. I'm bound to get *some* of them right. For the others, well, spring is coming and the fire pit is beginning to thaw out. ;-)
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The mark of a craftsman is being able to fix his mistakes...
John
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On 3/10/2015 3:38 PM, DerbyDad03 wrote:

When it come to making doors, methods can be cussed and discussed, but the two most important elements have little to do with methods:
Stock _selection_ (knowing which wood to use for doors, along with the way it was cut from the log, both key to stock that is less likely to warp, bow or twist).
And stock _preparation_ (consistency in thickness and flatness), are the two mandatory elements to successfully building doors (and the reason why we own jointers and planers).
More so than most any other woodworking endeavor, and much more so than the method used.
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On 3/10/2015 12:08 PM, DerbyDad03 wrote:

Snip

Your results and how long it performs well will be the indicator. Amana is certainly a good brand but like most brands there are varying degrees of quality.

Slightly snug with out glue is what you are shooting for. I have certainly had my share of questionable joints that were on the loose side but none have failed. Because looser fitting joints don't fit tightly to begin with the joints typically need more cleanup and sanding after glue up.
It pays to be anal. ;~)
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On Tuesday, March 10, 2015 at 4:01:18 PM UTC-4, Leon wrote:

Oh, trust me...I know about anal. That's why this is taking me so long.
Ya know, I still have some West Systems epoxy and 404 filler from my Derby racing days. If the tenons don't fit I'll just lop 'em off and make new ones out of epoxy. ;-)
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On 3/10/2015 3:31 PM, DerbyDad03 wrote:

You will be fine, just practice on same thickness and wood scraps. There is not much more you can do after you have the set up fine tuned.
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