Leigh Dovetails and Dewalt 618 Router


Anyone have experience with this combo. I have a D4R Leigh dovetail
jig and a Dewalt 618 router. Using good PC brass bushings I can not
get a workable halfblind joint in 3/4 sides and 1/2 fronts and backs.
After 8 attempts following every instruction I gave up. The joint
never really changed in fit. It started out tight. Per instructions I
raised the bit "Slightly" about 1/128 and cut new. Same result. I
eventually moved the bit up 1/16, no change.
I reset the fingers. They started out all set tight against each
other. I eventually put a 1/32 between each. Still no change in fit,
it was tight. Tight means the joint will not slide together. Tight
means trying to pound the joint together with a mallet results in the
wood splitting out. (OK that was frustration on # 6)
Finally I started looking at the router. The thing is so loose when
you release the adjustment lock I can adjust height by pulling or
pushing the base and get a 1/64 of an inch slop. Also and more
importent is the side to side concentricty of the bushing to the bit.
It can vary so much that the bit shaft contacts the bush. That can't
be good.
To allow for this I double routed the last two tests, as in hold
router one way, rout... turn router around 180 and rout again. This
method did produce the closest thing to a workable joint but still too
tight.
Anyone else experience anything like this?
OH 7/16 bush and a 128-8 bit starting depth of cut 3/8
Thanks
Larry
Reply to
Bubba Wood
Ok, you mention Joint, singular. If you are trying to correct an ill fitting joint, forget it. You cannot recut a joint. With each adjustment that you make you have to start with new wood. Why? Because the depth adjustments have the opposite effect on mating pieces of wood. One piece may get wider tails which requires narrower pins or visa versa depending on whether you make a deeper or shallower cut. Either way you cannot make previously made tail or pin cuts, narrower.
Because of this blind dovetails are unforgiving on any jig of this style regardless of what router you are using. Every DT bit has its "sweet spot" as to which depth it is going to cut correctly at. You should have scrap pieces of the same type of that you are going to use. Thickness is not really a factor assuming your finger template is resting flat on top of the wood although same thickness is easier to test with. Correct bit depth will be the same for any thickness wood. Make practice cuts until you get the right fit and then record that depth setting for that bit for future DT's. Simply cut the pins and tail off if the fit is not right. DO NOT attempt to "fix" a cut. Start over after making depth adjustments. As you mentioned, if the fit is too tight make a shallower cut. Too loose make a deeper cut.
A few other things to consider. Do not rotate the router when cutting the DT's in case the guide bushings are not perfectly centered to your bit. Be certain that you clean out all the area between the jig fingers when routing. If you unintentionally leave a little extra in there the fit will be too tight.
Reply to
Leon
"Leon" wrote in message
Just as aside in the event the OP missed it.
As you point out, the depth of cut in half-blind router jig cutting determines the fit, and with the Leigh jig you really need to be using an 18 degree dovetail bit for half-blind joints when using 1/2" material for the _fronts and/or backs_ of drawers.
... otherwise the fit will give you fits.
Reply to
Swingman
If you have the plunger in the 618PK, use that. You can eliminate the target depth issue. Plungers can be adjusted in very small depth increments. See the
formatting link
link. ******************
Reply to
pat
I'll keep that in mind. I have never used any other bit size other than the one that I have always used for blind DT's. Because you do not want a blind DT to become a through TD, :~) it makes sense to use a greater angle shallower cutting bit for the blind DT's.
Reply to
Leon
Thanks Leon but no help. Eash test was on fresh wood. I stated the bushing was definatly NOT centered and its position can not accuratly be set from change to change.
Reply to
Bubba Wood
Thanks Pat, I thought of that today. It is a more stable base. I'm sure the problem is the base>bushing>bit centering and the fact that the locking in position on the fixed base is hinky at best.
Larry
Reply to
Bubba Wood
The bushing does not absolutely have to be centered to achieve a proper fit within the tails and pins however if the bushing is not properly centered the mating pieces tend to not align properly on the tops and bottoms of the pieces. Again do not turn or clock the router while cutting. Keep it in one position.
Additionally, you mentioned that you adjusted 1/16", that still may not be enough.
Reply to
Leon
Thanks everyone I figured it out. Not the router or the jig or the bushings. The pin board was cupped. Two light passes through the jointer and new dovetails, everything is fine.
Larry
Reply to
Bubba Wood

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