what size bit for housing 18mm MDF from B&Q

[John McM]

If it's not a daft question. 18mm is too small, 3/4" is a bit loose, what does every one else use? or do I have to make do with tapping the fence over?
Many thanks

 

[Gary]

How loose is the 3/4" slot?

3/4" is a shade over 19mm so you may find a 19mm bit is the one to go for else its a fine adjustment with an 18mm bit.

Incidentally when you measure the MDF is it 18mm? Measure the MDF and you'll have the ideal cutter size, I guess it will be 19mm.

 

[Harbo]

You could always do two cuts with a smaller cutter?

Rod

 

[jasonB]

Don't measure or test fit the factory board edge, cut at least 100mm into the board, cheap "contract" grade MDF will be a bit swollen at the edges.

Jason

 

[OPJ]

I find that a 3/4" cutter works well for me.

Alternatively, check out the current issue of British Woodworking - Steve Maskery has made an excellent, fully-adjustable housing jig that'll allow you do rout out any sized housings using a smaller cutter - just use an offcut of the MDF as a spacer to set the jig. :wink:

 

[John McM]

Thickness seems to be a shade over 18mm. 3/4 bit lets panel wobble slightly in housing, might be ok when glued and pinned. Can you get different grades of MDF? I use B&Q for it as it's so cheap. Wealden do an 18.5mm cutter but are out of stock. I'll check out that housing jig anyway. I was jusr curious as to what others do.
Thanks gents.

 

[Argee]

Can you get different grades of MDF?

You certainly can and - like most other materials - you get what you pay for.

Many now use moisture-resistant MDF (MRMDF) because of its much denser construction and its ability to take a sharp profile without difficulty. Particularly useful for kitchen cabinet doors, drawer faces, base cabinets, kickplates, etc., but it is more expensive.

Look at the core of the typical shed's (B&Q, Focus, etc.) MDF, then pop into a timber yard and see the difference - again, for a small premium.

jasonB is more knowlegable than I am, but I think I've covered the basics.

Ray.

 

[mailee]

Although I have not seen the latest British Woodworker it sounds like Steve Maskery has the same jig that I use for my housings. It is easily made and can be adjusted for any thickness of material. I always use this jig as once set up to the thickness of the material it is so quick and accurate. HTH. :wink:

 

[jasonB]

As Ray says there are a lot off different grades and qualities within these grades.

The low price you pay for standard MDF in the sheds is a direct result of the amount of wood pulp that goes into making the board. There is a lot of air in the boards which results in a very "fluffy" cut edge as the fibres are not as tightly compressed. This will become very apparent when you try to paint the boards

For this reason I do not use standard MDF prefering to buy MR MDF usually by Caber though Medite is about the same quality. The slight cost difference is cancelled out by its easier working & finishing qualities.

Medite has a thickness tollerance of +/- 0.15mm on 18mm boards, expect this to be a lot higher on the cheap boards. Also if you buy a bit to fit the current boards there is every chance that the next batch will be different even if B&Q source from the same supplier :!: Thats why I join my carcases with biscuits :wink:

Jason

 

[Niki]

Hi John

You can make this jig....
http://www.woodmagazine.com/woodworking ... -dado-jig/

Another jig....Click on the "Online Extras" to see the video
http://www.shopnotes.com/main/sn76-toc.html

And another video...
http://www.youtube.com/watch?v=giengB-e ... re=related

Regards
niki

 

[Jake]

The MDF in the B&Qs near me is made by Medite.

 

[John McM]

Blimey, cheers chaps. Where do you buy MR-MDF? Do builders merchants have it or somewhere like Howdens?

 

[BradNaylor]

John,

Travis Perkins sell MR MDF - but the quality is not the very best! I buy mine from a specialist sheet materials supplier - there must be one locally.

As for the router cutter - I use an 18.2mm cutter from Trend for exactly this job. It's what its designed for. The fit with 18mm MDF is absolutely perfect!

http://www.trend-uk.com/en/UK/product/4 ... meter.html

Dan

 

[jasonB]

Have a try of Edens, they have a depot on the south coast. Keep MR by Caber, Medite & kronospan.

Jason

 

[John McM]

Brilliant many thanks everyone, lots of alternatives to play with now.