Biscuit Joiner or Dowels

[Derek Cohen (Perth Oz)]

I am going to disagree with all you wrote. There are many myths about the strength of mitre joints. Here is some reliable research:



Are you sure that you shouldn't be looking at a more serious mechanical joint like a dovetail?

Mate, he is just starting out in furniture making. While you are at it, suggest mitred through dovetails

As it happens, I have done these many times. Here is one with rounded dovetails ...

The mitres of this rebuilt turntable and its base have no splines ...

Regards from Perth

Derek

 

[Brdy]

To the OP - not having seen your designs I can't comment fully, but I assume that your mitres are structural to some degree - without knowing what loads they'll have to resist.

A biscuit is more of a locator than a profound structural joint. It increases glue area slightly but has limited resistance to tensile and racking strains. Are you sure that you shouldn't be looking at a more serious mechanical joint like a dovetail?

Thanks for the info.

I am basically looking to start with pine as it’s cheap and I can practice on it. Eventually I would like to use oak so am looking to practice neat and tidy jobs on pine first.

Please see the photo attached in regards to the type of joint I’m looking to achieve on coffee tables, side tables and bedside tables.

 

[Spectric]

Dowels are a long defunct system. They're used in chipboard, and thats about the sum of their usefulness.
Difficult to align, they dont make a strong joint as the hole is nearly always sloppy. In all, dowels are best left where they are.

Have to disagree, if that was the case then why does Jessem make a very good dowel jig and @Peter Sefton bothers to sell them knowing woodworkers workshop only tend to sell quality products. Both my Dowelmax and this jessem jig deliver precise alignment unlike my domino that uses a sloppy setting to allow joints to close. The dowels need to be fluted otherwise they cannot be driven in as the glue hydraulic's and if using MDF then the sides burst out unless clamped so no loose dowel holes. Then onto strength, you have to use the right method for the given application so most jointing methods are good and bad depending where used, look at these dowel joints made with a dowelmax and 10mm dowels, the Jessem can do them with 12mm dowels and no issues with alignment.

There are plenty of sites that discuss the virtues of every joint imaginable and they all have there place, dowels being functional, dovetails good looking and M&T traditional but many woodworkers just want a decent strong joint without any fuss.

 

[rogxwhit]

Thanks for the info.

I am basically looking to start with pine as it’s cheap and I can practice on it. Eventually I would like to use oak so am looking to practice neat and tidy jobs on pine first.

Please see the photo attached in regards to the type of joint I’m looking to achieve on coffee tables, side tables and bedside tables.

Ok, so it's quite structural. Imagine someone accidentally kicking one of the ends at floor level - that'd be quite some stress on the joint. In one of the pics I can see a rail under the top that would connect the ends and give reinforcement. Something like that could be a key to the whole thing working ...

 

[Brdy]

Ok, so it's quite structural. Imagine someone accidentally kicking one of the ends at floor level - that'd be quite some stress on the joint. In one of the pics I can see a rail under the top that would connect the ends and give reinforcement. Something like that could be a key to the whole thing working ...

My apologies the picture wasn’t a great example. I do intend to do a complete 360 degree structure of some sort, but was just showing a picture of the edge, if I made a coffee table it would have a support at the bottom linking the 2 legs.

 

[XTiffy]

I am with Derek Cohen on this one, I have built a great deal of veneered furniture and after many trials settled on a glued mitre joint, I have never had a joint fail and I have a mdf computer bureau (that I made) still in use after more than 20 years. Also don't agree with negative comments on dowel joints Mafell make a great dual doweler that is extremely accurate. I have one and will be selling it soon. Problems with knees (on the waiting list for both knees joints to be repaced) mean I can't stand for any reasonable period in the workshop so have to be realistic!

 

[Spectric]

Hi @XTiffy How do you cut the mitre on the two pieces? Also do you use anything like biscuits or dowels to reinforce, and ever considered the lock mitre joint ?

 

[Reffc]

With modern glues I think it's less important to reinforce some mitred joints as long as it's not a high stress application with cantilever forces acting on one or both sides. I've used plain mitre joints in plywood without any reinforcement and all have been fine and none have so far failed. The lock mitre joint is excellent but it can be a real faff setting the lock cutter accurately in the router table. I did try it a few times and it took a lot of trial and effort despite using an accurate depth gauge to set it exactly. Others may be more practised!

 

[Spectric]

Hi @Reffc you hear that a lot where the glue is stronger than the wood, the problem is accepting that so I reckon many including myself go further than may really be needed. With lock mitre cutters I use these to set them up

https://www.infinitytools.co.uk/accessories/lock-mitre-jig/

 

[Reffc]

Thanks Roy, that's a great spot and I may well give these a go myself. Yes, I tend to go belts and braces on most joints myself but admit the mitres I use are generally for very small enclosures and not under much stress.

 

[Spectric]

The other thing the lock mitre is good for is joining boards, run one through face up and the other face down and a larger glue area and instant alignment.

 

[XTiffy]

For veneered MDF (which I mostly used), I would cut mitres on a sliding table saw, with tilted blade always used scraps to check settings. I have tried lock mitre router cutters but the material has to be perfectly flat and uniform in thickness for them to work so only ever used them with solid stock that could be sanded at the mitre joint.