Festool 1400 and Leigh Dovetail Jig - Tearout (My Fault)

[Neill]

I have an older Leigh Jig, the D-4.  I have not used it for about 9 years.  I decided to reacquaint myself with it this week.  I had always used either my Porter Cable 690 or DeWalt 621 with it.  No problems noted.

Well I tried using it with my 1400.  In no way am I saying that the router was at fault, but I just need some help in determining what I was doing wrong.

The first tail board I cut was 3/4" African mahogany.  I set the router speed at 6.  It absolutely tore the first set of tails up.  I lowered the speed to 3 and it did a little better on the second set.

I then tried cutting tails in 3/4" pine.  With the router set at 6, it cut both ends of the tail board fairly well.

I know the problem is with me.  I think I was somewhat apprehensive about the whole process and may have been forcing the cut.  I don't think it was the sharpness of the dovetail bit since I have not used it that much.  Could the type of material have contributed the this gosh awful tearout?

Unfortunately, I did not get the chance to try it again last night.  Hopefully one of you experts can provide some guidance.

Thanks in advance.

Neill

 

[tbellemare]

I'm not expert at dovetails, Neill, but you might try taking a shallow scoring pass across the whole jig before plunging all the way in.

Tom

 

[Rob-GB]

Neill, let's go back to basics [wink].

When cutting dovetails by hand, the time honoured process starts with marking out, usually with the use of a marking knife and a cutting guage.
Both of these not only mark the cut lines but also give the saw a line to follow. The underlined cutting guage is possibly more important as it scores the cross grain part of the joint, preventing tearout while marking the line of cut parallel to the end of the piece.

What Tom said is correct, use a light scoring pass in the timber, when using a router and jig. This will mimic all the tedious marking out/scribing I mention above, the jig will have done all the pseudo marking out in your set up of it. Thats what it is for, to expedite the process.

I sometimes think that to go directly to machined solutions to woodworking tasks, prevents a foundation of 'why' things are done.

Hope this helps, Rob.

 

[Neill]

Tom & Rob,

Thank you so much for the great advice and for taking the time to respond.  I watched a WoodWhisperer video about the Leigh D4R yesterday before I made my cuts.  He said the exact same thing about the scoring cuts so I was aware of that.  I did not bother yesterday because I was just practicing and was willing to accept some tearout on my practice boards.

I guess I wasn't clear enough in my first post.  I am not talking about some broken wood fibers, I am talking about the tails being really chewed up.  [eek]

As I said, I approach using a dovetail jig with much apprehension.  You are balancing a piece of equipment in your hand with as much power as a small lawnmower and guiding this odd shaped piece of metal through a maze of extruded aluminum fingers, all the while with sawdust blasting you in the body and face.  So much to think about...

Will the bit clear the collar?  Is the cutting depth correct?  Is your material square in the jig?  Do you like the pattern?  Keep the router flat on the fingers>  Etc., etc., etc.

All I can say is that when you get it right,  WOW!

Neill

 

[Rob-GB]

tails completely chewed up!

Feed speed or dull cutter are the main culprits, though the grain direction/pattern in some timbers can have a large influence. That is, I'm sorry to say, an experience taught lesson.

Review what you did and look at the timber parts, see anything odd? Short grain or something?

Rob.

 

[DavidCBaker]

Neill,

You can see the remnants of a scoring pass (toward the left) in this photo:

 

[Mac]

As I said, I approach using a dovetail jig with much apprehension.  You are balancing a piece of equipment in your hand with as much power as a small lawnmower and guiding this odd shaped piece of metal through a maze of extruded aluminum fingers, all the while with sawdust blasting you in the body and face.  So much to think about...

Will the bit clear the collar?  Is the cutting depth correct?  Is your material square in the jig?  Do you like the pattern?  Keep the router flat on the fingers>  Etc., etc., etc.

This is why I've always been hesitant to even try too...maybe I just need to bite the bullet though and give it a go!
Let us know how it goes if you try it again Neill, my friend.

Take care,
Rick

 

[Neill]

Rick,

While you were responding, I sent you an e-mail.

Neill

 

[Mac]

Thanks Neill. Check your inbox.

R.

 

[justinmcf]

hi neill.

i use the of1400 and the leigh d4r.

i leave the speed at 6 and it works beautifully.

i suggest you slow down your feed rate.

it can take me 5 or 6 passes to completely cut out one dovetail using the d4r.

make sure you use a backing board behind your work piece as this will prevent chip out as the dove tail cutter removes the last piece of material.

justin.

 

[bonesbr549]

I have your set up and used the 690 as well.  I set up the strait bit in the 690 and the DT bit in the 1400.   I've not had the issues you experience and i'm running at full speed.   I use a backer board usually MDF and since mainly I use it for drawers I'm cutting maple(pretty hard), but I did make my nieces cedar chest (d4r) and no issues in red oak (and it splinters a lot) I've also done cherry without issues.   Now I do use a scoring device (Tite-mark from lie-nielsen) and run it around my pieces to break the fibers and it helps a lot and when you look and see the faint cut line on the finished product it adds to the look of the hand cut dovetail.    Another suggestion I cut my pieces (sides and backs and fronts) extra extra long and make a few test cuts with actual pieces cutting off the practice each time till I get her zero'd in and then cut the remaining to final length score the line and have at it.  It ain't failed me yet.   I still go back and watch the videos each time.  I use to use pine and poplar to test but it don't simulate the real thing.   I  can't remember who suggested leaving them extra long to practice with the real mccoy and just whack it off .  Works though.  I've never had to go to many shots before it's perfect.   Two routers helps on speed.   Love the 1400.   Have a good one.    

PS I almost forgot, one of the best things I did was get the VRS attachement.  It adds balance and stability like you would not believe and helps remendously with the DC. 

 

[Neill]

Thanks to everyone who took the time to respond to my query.  What makes this site so great is the worldwide membership who unselfishly are willing to share their knowledge and experience with everyone.

I am not giving up.  I know that I can do it.  I did it before.  I will try everyone's great suggestions and overcome my anxiety.  I will try to slow my feed rate, use a backer board, and a scoring line. The scoring line appears to be more important than I thought.

I also like Bones' idea of using a longer board to perfect the cut. But first, I need to get my overall technique down.

Bones, I just recently found out about the VRS since it was not available when I bought my D4 many years ago.  I will probably spring for it since it is supposed to help significantly with the dust collection and router stability.  At about $100, it seems like a bargain.  I am just glad that Leigh built a version that fits their older jig models.

With the holiday weekend coming up I will have some time to work some in my shop. Hopefully no fireworks will come from there.

Neill

 

[mattfc]

I tend to do a very light climb pass first, and then in general just take it slow, lots of light passes (depending on how close you have your jig fingers set at, if you have enough room I route the middle first, and work out slowly to the jig fingers), never have had a problem doing it this way. Also what made a big difference for me was switching to spiral upcut bits for the pins.. but I guess from your post its the taisl rather than the pins you are struggling with.

Another thing I do (I might well get shot for saying this from a safety perspective), it to put a full face visor on (e.g like for lathe work) and hve the jig higer, so I can see the bit, and guide the router looking both at the template, and the cutter to make sure I don't chomp too much off.

 

[Neill]

Matt,

Thank you. Very nice post. Most appreciated. Yes I had trouble with the tails because I did them first. If I had done the pins first, they probably would have been the problem.  I have not gotten to the pins yet.

I am confident, with the excellent advice I have gotten here, I will get it right.

Neill

 

[mattfc]

Ok.. good luck and let us know how you get on.. (p.s. forgot to mention that I have the VRS.. extraction is always going to be a little hit and miss, but the added support is great). Just take it little by little and slowly, this will always be quicker than having to start again on a new piece. Also you might want to use some PTFE spray on the template fingers, as one thing I did struggle with a little sometimes was the friction between the router base and the jig, which just makes it that little bit harder to smoothly control router movements.

Here is what I last used my jig for

http://festoolownersgroup.com/member-projects/walnut-toy-chest/

 

[Neill]

Thanks again to everyone.  I guess I can't say it enough what a great place this is to be.

By jove, I think I got it.  Rob was correct about the direction of the grain.

I tried everything suggested and still the tail on my African mahogany was ripped to pieces by the dovetail bit.  The pine I had cut the other day was relatively OK.  So I got to thinking what was different.  It suddenly hit me.  These were practice pieces from cutoffs.  The pine's grain was vertical to the jig as you would ordinarily cut a dovetail.  The mahogany was running horizontally to the jig.

I never thought about the grain having an effect because I guess I never tried to cut dovetails across the grain before.  I'm sure there are, but I cannot think of a situation where you would want to cut a cross grain dovetail.

To make a long story a little shorter, I recut the mahogany tails and pins going the right way, and it all worked.

Neill

P. S.  Matt, what a magnificent chest.  Very nice work.  I think I commented on it when you originally posted.  I also got the tip about "lubricating" the base plate and fingers from a WoodWhisperer video.  Still, a great tip.

 

[Rob-GB]

Neill, I am glad you took the time to reflect on what you had done differently, it was how I learnt that jigs, while making repetetive tasks faster, they are still not smarter. [wink] When we play with wood, regardless of the species, we need to take a moment to 'read' the grain. This helps not only in the machining process but has great aesthetic value too.

As for cross grain dovetails David did some that worked out here:- http://festoolownersgroup.com/member-projects/first-attempt-at-dovetailing/
2nd post, third picture.

Regards Rob.