Router or Biscuit joiner for shelving unit

[Game of Throw-ins]

Hello everybody.
I'm new to the forums and I'd like to ask the advice of people on here. I'm going to be building a shelving/desk unit out of 18mm MDF and would like some advice on joining. (Picture attached)

I've been planning on making housings (or dados/trenches depending on your naming preferences) for most of the horizontal joins and screws wherever i can. I'm getting all the MDF cut to size down the road from me but cutting the grooves i'm leaving to myself. I was thinking 18mm wide by 4mm or 3mm deep.

I'm going to have to buy the tool for making the joints and don't want to spend more than around 100 quid. And here start my questions:

1: the machine -

I was thinking about the Bosch POF 1200 router with an 18mm straight cutting bit. I know green Bosch is for DIY'ers but not really sure how rubbish that makes it. Any other suggestions for a half decent cheap router?

Or i could go with a biscuit joiner. Although all the brands that i've heard of are out of my price range. I'm hesitant to go for some off-brand machine thats 4 times cheaper like Einhell or Holzmann. Not sure i want the cheapest of Chinese plastic being the only thing between me and a metal blade spinning at 10000 rpm.


2: Technique -

Is a 4mm groove too much? This thing is going to weigh a ton so i kind of WANT to go overkill on the joints.

Is an 18mm cut too tight for 18mm MDF? I know i could cut the groove, making tape the fence and take another pass, but i'm going to have a lot of these things to cut and sticking and peeling off masking tape for each one would be a pain. I've seen 19mm bits with a 1/4' shaft too but would they be too loose?

I'm planning on gluing with an acrylic based glue rather than PVA so the glue sets nice and hard.

Any advice will be appreciated.

 

[paulrockliffe]

It's a risk to assume your 18mm router bit and the 18mm MDF boards are the same width. There's a lot of stuff out there that is quoted in mm but is made by imperial machines, so often the mm dimensions are slightly out. I don't know about MDF making machines, but a lot of my 18mm sheets are closer to 19mm.

What I use for housings is a pair of T-squares that act as a router stop. I use a half inch cutter and set the T-squares far enough apart that the router can be moved enough left to right so that running the router down one T-square, then against the other leaves a housing to match the MDF.

I clamp the T-squares to each other because I haven't got round to adding some slots and bolts. This lets you repeat the width of housing once you've set it up once.

Test cut and fine tune the setup and you can get very tight housings pretty easily and repeatable.

 

[paulrockliffe]

Alternative approach is to use a router collar and a suitably wide slot cut through a piece of ply or MDF to achieve the same result. A better option if you're going to repeat the cut a lot and you can easily make an accurately dimensioned slot. The first method is easier to setup through trial and error, but if you have a router table and fence you can nibble the slot gradually to get the dimensions exact.

 

[Graham Orm]

Here ya go. https://www.youtube.com/watch?v=WIRptl0OlvE or https://www.youtube.com/watch?v=7j4vGS4HY-8

Router rather than biscuits.

The Bosch will be fine.

Edit: Just done a very quick search, can't make out if it's half inch drive or quarter? You need half inch drive for an 18mm bit. If you use the jig shown in the video you can get away with a smaller bit, but I'd still go for half inch drive, it gives you more options in the future.

PS Welcome to the forum. :wink:

 

[Game of Throw-ins]

Thanks for those videos, but it looks like im going to have to go for somekind of hybrid solution for a jig - kind of like what paulrockliffe is suggesting.- I've not got the tools to make the jig precise enough, no tablesaw, no mitresaw, no workshop

The bosch can take a 1/4 inch shaft. But i have seen 18/19mm bits with a 1/4 inch shaft, im assuming that you reckon they'll put too much strain on the router?

And unfortunately the 1/2 inch drive routers i've seen on the internet fall into 2 categories: Makita, Dewolt expensiveness or Silverline cheapness. Not had good experiences with cheapo powertools. (apart from an Aldi power screwdriver which to be fair to it seems indestructible for 20 quid)

 

[mseries]

I recommend you make a jig like in the first video, I use one. You can use any size router cutter that's smaller than the width of your housing. For a 19mm housing a 12mm or 1/2" cutter will suffice. Take several shallow passes and don't attempt to push too hard. Let the cutter do the cutting.

 

[Graham Orm]

I would suggest that you do some homework on the cheaper half inch routers. Search for reviews of them and buy the best option. You will upgrade later when you can afford.....or desire overcomes finances. You will be able to make the jig using your router alone using a straight edge and bearing guided straight cutters.

https://www.youtube.com/watch?v=FQImTCJbo3c

 

[deema]

Biscuits are excellent for making this type of unit, the traditional approach would have been to use dowels, and a very cheap Record (I think it's a 145) dowel jig from an auction site is an excellent investment and is very, very useful for all sorts of stuff.

You can consider lipping the shelves front and possibly back that will add strength and help to reduce any sagging. It also makes a nice finish to the shelves and vertices. You can obtain a couple of router bits that will make adding lipping very simple, as it aligns the lipping and the MDF through a tongue and groove / chamfer that forms an incredibly strong joint. You can make the lipping thicker both front to back and depth if you need extra strength. By making the lipping thicker it can provide a nice overhand under which you can add an LED lighting strip to add illumination to any / all of the shelves as a feature.

 

[Shultzy]

If you are going to put edging or lippings on the front you could use a 6mm loose tenon which will not put a strain on 1/4" router bits. Personally I would use biscuits, very easy to do. A have a cheap Clarke which has lasted, but then again I use it infrequently.