Biscuit joints - beginners question

[kingcod]

I am disappointed with the biscuit joint I ahev made so far. I have the correct size set on my jointer (20), and have been joining MDF. The problem is I cant get the joints to come together flush - I always seem to end up with a gap between 1 and 5 mm. I am gluing straight into the joint, inserting biscuits, then marrying up the other piece. Tapping into place with a mallet seems to do no good not does clamping down.

Am I missing something? I sense the biscuits are either too big or the jointer is not cutting deep enough. Whats the trick?

 

[MickCheese]

Do you have a 3.5mm blade or a 4mm blade in your jointer.

Not all biscuits are the same thickness.

My jointer was not properly set from the factory. Cut a slot, put a biscuit in dry and draw a line along it, it should be a little over half deep. If not adjust the blade protrusion.

Mick

 

[big soft moose]

also if you are gluing up one side before the other the application of glue to the first side can cause the biscuit to swell meaning that it is a poor fit on the second joint.

try a dry fit before you glue anything - if that fits fine then this is the problem - and if so the solution is to apply the glue to both sides at the same time and clamp up while the glue is still wet.

 

[woodbloke]

You don't say what make of biscuit jointer you're using - Rob

 

[xy mosian]

The first time I used a biscuit jointer I had the same problem.
It turned out I was not lining up the two halves of the joint.

xy

 

[kingcod]

You don't say what make of biscuit jointer you're using - Rob

Its a Clarke from Machine Mart

 

[moz]

If the slots are aligning correctly but you cannot close the joint, the blade is not cutting deep enough. As well as the biscuit size selector, there is always a fine adjustment screw which, from the sound of it, has not been adjusted very well. On yours, the screw can be accessed using a pozidrive screwdriver inserted into the hole to the right of the motor (see illustration http://www.machinemart.co.uk/download/BJ600.pdf - page 9 fig. 1)

John

 

[Karl]

1-5mm is a big gap. When you insert a biscuit into one half of the joint, does it go more than half way in? If not, there is the problem.

You could try setting your cutting depth to "Max" if it has one, and see if that works.

It sounds to me as though you may be trying to get No 20 biscuits in a No 10 slot.

Cheers

Karl

 

[Benchwayze]

I had the same problem when I first used a BJ. I had to adjust the depth of cut a fraction deeper than the setting on the jointer, to allow expansion room for the glue. If the biscuits, are thicker than usual then it's a case of cutting every slot twice, and moving the blade across a smidgeon for the second round of cuts.

Whatever you do, don't try 'waggling' the cutter. That only works well with drills!

I never much had this problem mind. Usually it's just the odd biscuit that is too tight! I just bin them.

Hope your Clarke serves you well until you're in a position to buy something better. Mine did!

HTH
John

 

[woodbloke]

You don't say what make of biscuit jointer you're using - Rob

Its a Clarke from Machine Mart

The reason for asking is that there are probably adjustments on the machine to alter the depth of cut and there evidently are, as others have indicated. I know nothing about the Clarke machine so can't really advise on why the depth of cut is too shallow. I use a Lamello which doesn't suffer from these sorts of problems...if you're in the position to change your Clarke at some time in the future, then the Swiss machines come highly recommended - Rob

 

[OPJ]

I've just been reading the .pdf manual on the Clark jointer and, if you look at page nine (Fine Depth Adjustment), it tells you everything you need to know about increasing the depth of cut. All you really need is a pozi screwdriver.... Probably a no.2 although, it isn't mentioned.

 

[laird]

Which Clarke ? There's the yellow one which has a solid fence and the blue one which is altogether more delicate.

 

[kingcod]

The model is a Clarke BJ300. I see it has no fine depth adjustment listed in the manual unlike the meatier BJ600.

The depth of cut is 10mm for a 20 biscuit - and it is supposed to be 12.3mm - hence all my problems I think.

There is a small screw at the back of the machine (its part No 57 in the manual) but I wonder if that is just a backstop adjuster - it doesn't say.[/url]

 

[Argee]

I don't understand - page 6 of the manual you linked to deals with the fine adjuster and shows it clearly, as does item 53 in the exploded parts diagram on page 12?

Ray

 

[kingcod]

Ray - this adjustment is only between the 3 sizes of biscuit so does not adjust within the size setting. The setting for the size 20 biscuit is out by about 2MM.

 

[Neil]

There is a small screw at the back of the machine (its part No 57 in the manual) but I wonder if that is just a backstop adjuster - it doesn't say.

Going off the exploded parts diagram, it looks to me as though this is where you need to make the adjustment - just back the screw out by 2.3mm and then re-lock.

Cheers,
Neil

 

[moz]

I think Neil has it. But I can't see a locking nut so probably the spring 56 keeps it in tension, i.e. just back the screw out a little and that's all you need to do.

John

 

[kingcod]

I had an initial look at it - locked in very tight, and its a very small screw. My small screwdriver was just about to give in, even with some WD40 and I didn't want to damage the screw itself. I am guessing this was factory fitted to stay in place - hence its not referred to as an adjuster in the manual.

As an interim I am using undersized 10 and 00 biscuits in a 20 slot, but thats not going to be my long term solution. I've a mind to take it back to Machine Mart though its been about 8 months since I bought it and I doubt I still have the receipt.

 

[laird]

Have you tried simply 'phoning Machine Mart's technical support ? (the number's in the manual).