Biscuit Joint Question

[DaveL]

OK so I did not need the biscuit jointer, but it was on special offer 8) from Screwfix, so I ordered the Ferm FBJ710 and a bag of 100 biscuits of each of the three sizes.
It arrived a few weeks before Christmas and now I am making something that I could use biscuit joints on
In the best workshop :!: practise I made a test joint in the off cuts from the project. I have never use a biscuit jointer before, hence the question:

How deep should the slots be for a '0' biscuit?

In my test cut with the depth stop set for '0' biscuits, the slots are 12mm deep, but 0 biscuit is only just over 15mm wide. This seems to me that the slots are too deep. In fact the 10 biscuits that I have are just under 20mm wide and I feel that they 'fit' the slot better.

There is an adjustable stop on the side of the jointer, but before I lay into it with a spanner I thought I would ask for your advice.

So advise away :!:

Thanks, DaveL

 

[bobthejoiner]

davel
the idea behind the buiscut joint is that the buiscut when inserted with glue expands to gain a tight "fit" so the stops for the various sizes is very relevant ie if you cut for an number 0 and then fit a number 10 the buiscut may expand too much and split your timber. It is also a good idea not to keep your buiscuts in your garage/workshop as they are very hydroscopic ie take up any moisture from the atmosphere and this swells them prior to fitting . I keep mine in the house in a dry atmosphere.


hope this goes some way to help you .
Cheers BTJ

 

[DaveL]

Hi BTJ,

Thanks for your comments.
I know that the biscuits absorb moisture from the air so I have put them in sealable jars, with little bags of silica gel that I had .

The bisciuts fit the slot for their thickness, but the 0 biscuit when pushed home in the slot only has 3mm sticking out to mate in the other half of the joint.
I have searched on the net and found this page:-
http://www.huntfamily.com/metz/joinereval.htm
This chap suggests that to check the depth of plunge is correct for the biscuit, you insert a biscuit, mark a line on it, rotate the biscuit 180 degrees, re-insert it the and mark another line. He sets his up with 1/16" gap between the lines, so I tried this with my setup.
With a slot cut with the jointer set for 0 biscuits
0 biscuit has a 9mm (3/8") gap :shock:
10 biscuit has a 5mm (3/16") gap :?
20 biscuit has a 1mm (1/32") gap

So I am going to wind the stop out by 3mm and check again. Just need to find the small spanners now :!:

DaveL
off to play with newest toy :lol: , I mean use the newest tool

 

[Charley]

Hi Dave,

I might be to late but, I've just looked in my biscuit jointer manual and its says;

A #0 biscuit needs a 8mm deep groove..


Hope this helps

 

[DaveL]

Hi Charley,

Thanks, that confirms my feelings.
I have just set the jointer to cut a 8.5mm slot, not wanting to go to tight an split anything, so I could take it down a bit more. At least I know where the spanners are now!
I looked in the manual for the Ferm and it just gives a max depth setting, it was set much deeper.
I am not suprised that I have needed to adjust the thing, it did only cost £39.99 .

Regards,

DaveL

 

[sawdustalley]

I have the same biscuit joiner. I got it for £80 last christmas

I've never used No. 0 biscuits, they are too small and pointless in my opinion. I guess there good for mitred frames etc...

Never had any trouble with it. I did snap the handle off (My fault) and screwfix replaced it with no problems 8) - I've used No 10 & 20 biscuits with no trouble.