Minimising chipping when scribing MFC or MFMDF

[RogerS]

I need to scribe a rather convoluted shape on an melamine faced board (MDF I think) to fit round old beams and the like. Racking my brains how to do this with minimal chipout. Straight lines I can clean up with the router (although a decent blade in the Festool does a pretty good job in its' own right)....but curves??

 

[wrightclan]

I need to scribe a rather convoluted shape on an melamine faced board (MDF I think) to fit round old beams and the like. Racking my brains how to do this with minimal chipout. Straight lines I can clean up with the router (although a decent blade in the Festool does a pretty good job in its' own right)....but curves??

Can you scribe to a template of say hardboard? Cut to the scribed line with jigsaw or whatever. Then use the hardboard as a template for a bearing-guided cutter.

Brad

 

[Paul Chapman]

Hi Roger,

You can buy jigsaw blades with downward pointing teeth - would that be any good?

Paul :wink:

 

[Anonymous]

I wouldtry scoring first with a sharp utility knife first then use a good jigsaw. :?

 

[George_N]

I'm with Brad on this one. Make a template of 6 mm MDF, rough cut the melamine with a jigsaw and finish with a router and pattern bit. If that won't get into the tightest corners then Japanese pull saws give a very clean cut if used carefully.

 

[engineer one]

i would guess the answer should be to make templates, and
use those double ended spiral cutters. the up and down spiral
is supposed to stop chip out.

paul :wink:

 

[wrightclan]

i would guess the answer should be to make templates, and
use those double ended spiral cutters. the up and down spiral
is supposed to stop chip out.

paul :wink:

Expensive :shock:

I've had excellent results with standard TCT bits and MFMDF; also on veneered MDF. Never tried it on MFC. Wears on the bits, but nice finish.

Brad

 

[RogerS]

Thanks guys...some great suggestions and I'd not thought about templating it first. Reckon that's the route I'll go down.

 

[engineer one]

roger
i noticed last night that june popular woodworking, the american one,
has an article about template routing, might be useful.
pretty sure you can find it on the web site.

paul :wink:

 

[Scrit]

Roger

As with the others, template first (washer and pencil) then use a freshly sharpened TCT cutter. As soon as they blunt (an that can take less that 50 ft) they can start to chip. TC-RT cutters such as the Wealden (KWO) Versofix are the best bet and are the preferred choice of kitchen fitters working with 40mm thick worktops. Nice thing about TC-RT is that it retains constant diameter when you fit new tips, unlike brazed bits which can be awkward to use with guide bushes as they get smaller every time they're sharpened. If you need to trim further once done, then a belt sander does a respectable job when used on the edges

Scrit

 

[RogerS]

Templating worked a treat and the first time I've tried it.

Found setting the height of the cutter tricky as the thickness of the hardboard template was a bit too thin..dropping the cutter so that it just cleared the bottom of the material left me with very little 'meat' on the template for the bearing to guide against.

Pretty scary doing it as well as I couldn't work out any sensible way of guarding and so having that 1/2" cutter whirring away in the 'open air' focussed the mind somewhat.

The shorter scribe lines I did on the baby bandsaw and the finish was pretty good.