Tear out

[plymouth pirate]

Evening all.

I'm machining some Sapele veneered MDF and getting tear out.

Tried scoring the underside but must have missed the line by a few thou and still ended up with it. Getting close to not having many more chances.

Thought I could lay some hardboard under the cut but perhaps there is a better way?

Any suggestions gratefully received.

All the best

John.

 

[Steve Maskery]

HI John

By "machining" do you mean sing or routing As you have talked about scoring I shall assume you mean cross-cutting.
Scoring is an excellent approach, but you have to make sure that you don't cut over the line, which destroys the knife edge.

Another option is to tape the cut. Masking tape and gaffer tape work well, but there is the risk of pulling fibres off when you remove the tape.

What sort of blade are you using? The right tooth geometry is crucial with veneered board.

Cheers
steve

 

[plymouth pirate]

Hi, Steve.

Thanks for the reply.

I'm cross cutting across the grain of the veneer on the table saw. It's a Record universal C26+, with the original blade, which I assume is not the best in the world. I'm not experienced enough to know the differences yet, it's a retirement dream, getting into this sort of thing.

Regards

John.

 

[Steve Maskery]

OK
1 What is the diameter of the blade?
2 How many teeth does it have?
S

 

[plymouth pirate]

Hi, Steve

10" and 20

Regards

John

 

[TheTiddles]

There's several things you can try, masking tape being the easiest. To aid it's removal a heat gun on a low setting or a hair dryer is good at softening it. If that fails, which it probably won't, a secondary panel underneath it will definitely sort this. These are the cheap options, the expensive, easiest method, is a zero-clearance insert with a good blade, CMT is your friend here

Aidan

 

[joiner_sim]

The correct sort of blade for cutting veneered MDF will help. But also the masking/gaffa tape idea will also help.

 

[plymouth pirate]

Aiden,
What the hell is CMT?

Rgds
John

 

[Steve Maskery]

Hi John
Your problem lies in the fact that you are using the wrong sort of blade. 20T on a 10" is a rip blade, and you will never get good results on tender delicate veneer with such a bull-in-a-china-shop blade. As a guide, for 10" diameter:
20-24T - Ripping timber
40T - Crosscutting timber
60T- veneered board
80T - plastic laminate.

It's not just the number of teeth that count, the shape of them varies according to the task, too.

CMT is a brand name. Freud also do good blades at fair prices, and they are always my personal blade of choice.

I'm afraid you are going to have to spend some money!
Cheers
Steve

 

[plymouth pirate]

Many thanks, Steve, Aiden and Sim. Appreciate your replies very much.

Will go for a 60/80 tooth blade for a start. I am willing to spend on quality but like I say, I'm still (and probably always will be), an amateur with very little experience.
What would be your recommendation of a good blade manufacturer/supplier?

All the best
John

 

[OPJ]

CMT blades are available from Axminster. As for Freud, you can get them from Rutlands (mail-order only) or Toolstation. There are probably other firms who stock Freud blades as well.

 

[plymouth pirate]

Thanks OPJ. Ordering now.
Regards
John.

 

[crazylilting]

i'm with TheTiddles on this one.

CMT is http://www.cmtuk.com/formachinery.html

Zero clearance insert http://www.eaglelakewoodworking.com...-in-your-Zero-Clearance-table-saw-insert.aspx