Box Joints tearout

[Thornburn]

I have successfully used my LS positioner to make box joints before but am having trouble with the latest effort.

I am using the BOXD pattern on 6mm thick highly figured maple and a 1/4" Whiteside bit that is new. As you can see in the photos I am gettin the end torn out and some of the edges of the joint. It tends to only happen on the front piece of wood and so I placed a thin piece of sacrifical wood in front and behind to stop this but it seemed to have little effect.

Should I put I thicker piece of wood in front and if so what sort of thickness would you suggest?

Thanks

Thornburn

[underused]

Hi Thornburn,

umm..What speed are you running the router at? Maybe a change of speed might help?
Are you getting the sacrifical front board tight, up against the maple?
On the first, end cuts, you can creep up on them. set the fence so as just to score the edge on the first cut, then slowly in.
Dont force the cut through, take it nice and easy through the sacrifcal board, steadily continuing through the maple boards.
If that doesnt work, bugger, Im stuck:-

[Big Shed]

Haven't used my LS yet so can't give suggestions from experience. However, the end bits seem rather narrow, have you tried a different template where the end bits finish up slightly wider?

Have only had my LS since Wednesday and am still building the router table.

[Gumby]

rather than change templates to make the end finger a bit wider, just widen the initial stock a bit. It will give you a bit more timber for that last finger to hold on with.

As others said, watch your router bit speed but more importantly, the speed you feed the timber to the router. If you have a look at my video on the Gifkins jig (see Video section of the forums), I go through the process of scoring the cut first and creeping into it as you go.

[Thornburn]

Thanks Underused - I am running the router on the middle setting - Trition 3/4 hp. I think my problem lies in my sacrifical board - its only 3mm offcuts - think maybe I should make it at least 6-10mm and its also not super tight against the maple.

Gumby - good call with the width idea - I'll try it - & I'll view your video!

I'll also slow up my feed rate and see what happens.

Unfortunately now I'm away with work for 2 weeks so I will try these ideas when I get home.

Thanks

Thornburn

[TexasWoodRat]

Thanks Underused - I am running the router on the middle setting - Trition 3/4 hp.


Those joints look small enough to be running the router at maximum RPMs to me.



I think my problem lies in my sacrifical board - its only 3mm offcuts - think maybe I should make it at least 6-10mm and its also not super tight against the maple.


6mm would definitely be better but it could be 60mm and not do any good if it's not tight. Use a parallel clamp and get it down close to the top of the fingers and crank it down tight.

[Thornburn]

Thanks Texas,

I am using a parallel clamp but its probably not close or tight enough. I'll let you know
Cheers
Thornburn

[Thornburn]

Thanks guys

I tightened up on the clamp over the sacrifical board and it worked well!! Still got a bit of a "blow out" on the sides but I think that Gumby is right and all I have to do is widen the board somewhat and then cut it down. Anyway I'm pleased with the progress thus far.

The maple is so figured that it seems to "gouge out" chunks easily. Will keep you posted

Cheers
Thornburn

[Thornburn]

Hi folks
I just wanted to show the final results for the box that I was making at the start of this thread. I have posted this elsewhere (Woodwork pics) but wanted to also add it here to show the wonderful accuracy of the Incra LS system.

Again thanks for your advice on the tearout, I learn a little each time I pick up a tool !!

Thornburn

[Gumby]

I learn a little each time I pick up a tool !!



Don't we all. :)


Well done. :wink:

[munruben]

I just wanted to show the final results for the box that I was making at the start of this thread.
Excellent:2tsup:

[Gwhat]

G'day all,

These 8 posts just shows what this forum is all about, sharing ideas, finding solutions and best of all showing off the finished product.

From a practical point of view, I think that we tend to be a bit conservative on router speed which of course is directly responsible for the quality of cut. I think that all but the 5/8" bits in the Incra template set can run at full bore, subject to doing a few test cuts with the actual timber being used. Spacing of pins is always important to avoid likely problem areas.

Regards

The Woodworker

[martink]

I currently use CMT bits. I bought the Incra set because I've always been happy with them. It's inly when using the Incra jig did I actually check to see if a 3/8th bit really was a 3/8th bit...unfortunately not! Now I can shapen a router bit, bit cannot re-size one - if the whiteside bits are the size they say on the can I'm switching camps!

Ciao,

M.

[Mike Wingate]

I remove the waste at both the ends very gradually. Make sure that the cutters are sharp and there is enough power to cut. I have uprated my router by 200 watts. Everything makes a difference.

[chrisb691]

Mike, this is a 2 year old thread you've managed to dig up. :D

[Mike Wingate]

Yes but it was not here when I last looked in 1999. It is new to me and I have had a similar experience with my Incra jig. Taking just small cuts off the ends, rather than blast it all off solved my problem. I will try to keep more up to date.