liegh D1600 and chipout

[old_picker]

i done a few jobs now using through dovetails and am having a lot of trouble with chipout whch makes a prety untidy looking joint -

out of the 5 projects 4 have been in pine which i thought was the major contibutor to the problem - my most recent was cut from US oak and i reckon its as bad as what i had with the pine

i read up and carefully cut the tails and pins in the pattern outlined in the pretty cpmprehensive manual and its way short of perfect-
i would like to be able to cut dovetails so i dont have to use any woodfiller at all -

anybody have any suggestions??

[Stevenp]

Hi Ray, I have the 1600 and have had no problems with chipout. The only thing I can think of is make sure the support board is hard up against your workpiece to stop the bit from "Bursting" out the back.
Hope this helps , Cheers Steven:cool:

[Rattrap]

Hi Ray,
I use backing boards where possible to help cut down on chipouts. Also make sure your router bit is as sharp as u can get it. I'm not familar with any of the leigh type jigs, but i have done alot of dovetails on the woodrat - kind of similar. Where possible try to make climb cuts to minimise chipout. I've also used a blade to cut the wood fibers prior to cutting the dovetails where chipout is a problem.
I'm not sure how some of these fixes might apply to the type of jig u have there but hope it helps some.

[BobR]

I also have the 1600. If your chip out is at the back of the piece being cut then, as Stevenp says, make sure that the backing piece is firm against the board being cut. If the chipout is at the front make sure that you are doing the back routing before you move into the cut fully. This is only a very light cut to clean up the edge. Also pay attention to the diagram that shows to move the cutter into, across, and out of the area to be removed. It is also easy to have the router itself tip a little without realising it is happening. Hope this helps.

[old_picker]

its mainly cutting the pins so i cant do anything except push the router bit through the material - i am using a backing board for the pins -

the tails cut pretty clean so its chipout on the pins
i am using scrap pine as the backing board

to scribe cut the pins i would need to measure all the angles etc ?
lay out the whole job with a scalpel?

[rayintheuk]

its mainly cutting the pins so i cant do anything except push the router bit through the material - i am using a backing board for the pins -
It sounds like you're only having a problem when using the straight cutter, not the dovetail bit. If that's the case, then either the bit is not as sharp or new as it could be, or you're being too aggressive as you break through.

I tend to use a side to side motion, easing off the pressure as I near the backing board. I've not experienced chip-out in several years of using my Leigh (D4).

Ray

[old_picker]

It sounds like you're only having a problem when using the straight cutter, not the dovetail bit. If that's the case, then either the bit is not as sharp or new as it could be, or you're being too aggressive as you break through.

I tend to use a side to side motion, easing off the pressure as I near the backing board. I've not experienced chip-out in several years of using my Leigh (D4).

Ray

mmm i get confused wih the pin tail thing
its the the dovetal cutter not the straight cutter i am having trouble with
theres no opportunity to use a sideways motion as it can only go straight into the material the chipout is occuring at the rear as the cutter exits

do you change the backing board with each new piee of material?
i have been using the same backing board for the whole job
i change it with each job

should i use a denser material a backing board ?
i have been using radiata offcuts

[Rattrap]

As long as the cutter is cutting into fresh uncut timber then theres no need to replace the backing board. I've used radiata pine before as backing board with no probs. Check or resharpen your dovetail bit & make sure that your good timber is clamped up hard against your backing board. They are the only 2 reasons that i can think of to allow rear breakout.

[Stevenp]

As long as the cutter is cutting into fresh uncut timber then theres no need to replace the backing board. I've used radiata pine before as backing board with no probs. Check or resharpen your dovetail bit & make sure that your good timber is clamped up hard against your backing board. They are the only 2 reasons that i can think of to allow rear breakout.

:iagree: Each cut needs to be into "Fresh" uncut backer support board.

[rayintheuk]

Totally agree with Rattrap's and Stevenp's post above. Bit needs to be new or sharpened correctly. Just clamp tightly and ease off the pressure as you break through. I've found that you can control the breakthrough well if you hold one handle still and "rotate" the other one forward, rather than push equally on both.

Ray

[old_picker]

ok now i have some new techniques to try thanks for the intrest

i am building amplifier and speaker cabinets and some of the projects are 500 x 600 x300 not huge but big enough for me to get into all sorts of trouble

[mat]

Ray

A common problem is not having the backing board clamped tightly. I noticed even on the Leigh DVD that the backing board was pushed backwards during one of the cuts. If this happens you lose the backing board protection for tearout. There is a section in the hints and tips section about tearout but for the dovetail cutter the cure is basically the backing board and sharp cutters.

I use a spiral upcut instead of the straight bit for the other cuts and it works extremely well.

Are you using the original 8mm shank cutters?

[old_picker]

yes i am using the cutters as suplied
would like to get some decent cmt or carbitool cutters but i doubt they have this size shank -

i am nor sure how good the Leigh cutters are - mine havent done much work at all

[mat]

Carbitool have a suitable 8mm solid carbide spiral upcut but no dovetail bits with 8mm shanks, neither does CMT. Lee Valley sells some 8mm shanked bits that are suitable but my sources tell me they are made in the same Taiwanese Factory as the genuine Leigh bits.

Another though, are your backing boards thick enough to cover the whole dovetail cut from top to bottom? From memory break out is most likely at the top ie right at the end of the piece being cut.



THATS 1000:o

[old_picker]

mm thats a thought
if the depth of the backing board was less it would mean the base of the cut may be exposed

[mat]

Is that where you are getting the tear out?

[old_picker]

Is that where you are getting the tear out?
pretty much yes - worse at the bottom and its tearing splinters that will go to the top of the cut

[rayintheuk]

IME, Leigh's cutters are of good quality. The backer board must cover the entire height of the cut, otherwise you can get problems. I still suspect that the backer is not clamped close enough, or tightly enough. You need to break through on the left-hand side of the cut (when viewed from the front), then complete it by moving the router to your right. There should be videos of this somewhere, but I'm in a bit of a rush right now.

Ray.

[martink]

pretty much yes - worse at the bottom and its tearing splinters that will go to the top of the cut

Hey Old Picker,

The problem appears to be that the backer board is thinner then the depth of the dovetail, use at least a backer board the same thickness. Also make sure that the backer board covers then entire cut when your are setting the jig up - raise the fingers if necessary (this should become obvious when you fit the thicker backing board.

Also as others have mentioned, use the backer board once then trim it flush with your tablesaw/dropsaw/handsaw to make expose a nice flat face again before doing another cut.

The only other thing I can think of is drop the speed of your bit down a bit and move a little slower, this can also help.

Ciao,

M.

[BobR]

Just to add a little confusion. I don't find it necessary to have a new backing board for each cut. Once the first one is made you have created a zero clearance backer. This provides sufficient support for subsequent cuts. Anyway, works for me.

[Rattrap]

Following on from what bob just posted, it also cuts down on wear on your dovetail bit.

[lesmeyer]

I confer with Bob and Rattrap. A new backer is only required when changes are made to the spacing, depth etc.
Les

[Scally]

I have had the same problem with some timbers.

All the advice given should minimise your problem.

I prefer mdf as a backing boards because it gives a neat cut. That should give good support all around the dovetail.

I probably over tighten everything and even add extra clamps on tough pieces of timber. Router dovetails is an aggressive cut and I have managed to get the board to move slightly. It doesn't make a nice joint!!

My preference is to use the variable speed router and back it off a setting. Then take the cut steadily and let the cutter do the work.

I like the 8mm Leigh cutters. The quality seems good to me.

On a piece of really dry and cracked Zebrano, I added a board to the front as well as the back for extra support. It worked well. I had minimal chipping on either side of the cut.

[Rattrap]

When cutting out dovetails & finger joints i like to, where practical, hog out the bulk of the material on the tablesaw before i cut with the router bit. Takes so much pressure off the router bit especally dovetail bits giving u a cleaner cut with much less chance the bit will push the timber around as u cut.