RS Pro CNC MFT Jig Review

[porker]

Hi,
I have just purchased an RS Pro CNC MFT Top Jig and thought a review might be useful to someone. I posted it in Tool Reviews as this isn't a shop made jig. I hope this is OK.

I have been wanting to make an MFT top for ages primarily so that I can cross cut accurately sheet material for built-ins on my house renovation. I have a Festool TS55 which gives me great results but other Festool gear is more than I want to spend as a DIY'er. So, having looked around I discounted Peter Parfitt's excellent Parf Guide System (PGS) as beyond my pocket. I could have bought a replacement top but for around the same price I bought the jig as I like to be able to remake stuff.

I ordered the MDF jig and a set of dogs from their website and Rick confirmed when it had been dispatched. It arrived well protected and packed. The quality of the jig is superb as only a CNC jig would be. It is manufactured from 12mm Medite MRMDF and there are a couple of well fitting plastic 'dogs' included. Reading the instructions the jig is designed to be able to reproduce an MFT top exactly including accurate sizing and mounting holes by routing around the edge of the jig and drilling through the supplied plastic bushes respectively.

As well as the jig you need the material for the top (I used 18mm MRMDF but you could use ply), a 30mm guide bush for your router and a standard 12.7mm straight cutting bit. The guide bush is usually supplied with a new router as standard and the bit is a standard used in jigs for cutting worktops so I had the required kit. Also included is a strip of aluminium tape. This is to 'shim' your guide bush if required to get a nice fit on the dogs. Wrapping the tape around the guide bush will slightly reduce the size of the hole. I routed one hole in a piece of scrap and it was a lovely sliding fit so no need to use this.

So you clamp the jig to your MDF sheet making sure it is parallel to the edge and at least 12mm inboard. You then bore the first row of holes using the router with the guide bush. Once the first row is done, you turn the jig around 180 degrees and use the plastic dogs supplied to locate in the outermost holes of the row that you have just bored. You simply repeat this process moving the jig up to the next set of holes.

How did it go? Well, fine until I noticed a problem - not with the jig but with my router setup. I noticed that the router wasn't boring the hole concentric with the jig. It was obvious by eye it was that bad and seemed fairly constant. Because the jig references off the previous row (you can actually do two rows without moving the jig), any offset will accumulate the error as subsequent holes are bored
This picture shows what I mean by concentricity but strangely is much worse looking in real life. Also the hole looks a big raggy but is actually nice and sharp. So much for the camera never lies.

One item I saw mentioned somewhere is that wear or sloppiness in the plunge rails will also introduce errors as it affects the concentricity of the bit to the guide bush. My issue was simply that the guide bush wasn't concentric with the bit when it was installed. My router is an ancient Erbauer which I bought second hand years ago but it has had a hard life. I think a fixed base router would eliminate this issue. I am thinking of getting a better router (DeWalt, Makita or similar) but wonder if their accuracy is better? In the meantime I will make another as I noticed that I can centre the guide bush - by eye at least - to look far better. One thing I would say is that boring the 77 holes in a standard table took less than 20 minutes so it is a very quick system.

So in summary the jig accuracy is fantastic but your router needs to be able to bore concentrically as any error will be accumulated as you add rows. One last comment, the aluminium dogs are also very well made with an M8 thread for locking down. I will correct my router issues and have another go and am confident I can get an accurate top.

I hope that maybe helps someone who is looking at this system as I have seen a few PGS demos but not so many on this method.

 

[Eric The Viking]

I'm afraid I bottled it:

I've just bought their pre-drilled top and table. The top is probably for places in the house that I can't take the table. They haven't arrived yet, but I've heard nothing but good things of them.

I don't think you are alone in finding the process difficult. It's what put me off.

 

[porker]

I don't think you will be disappointed, the quality of the jig is fantastic so I'm sure their tops are too, just my router let me down.

I moved 3 years ago and only yesterday used my metal lathe for the first time to make a centering tool to get the guide bush er.. centered. Just a bit of aluminium bar turned the same diameter as the inside of the guide bush and reamed in the centre to 1/2". I got a precision ground 1/2" bar from an old printer which I cut a bit off and put in the router collet and used the ally bush to centre up the guide bush. Only issue is that there is not quite enough adjustment on the router so I reckon its still a thou or two out. Been looking at the Hitachi router as a replacement and also saw the Trend unibase but it gets some bad reviews on Screwfix due to poor manufacture. Anyway may have a go at another top at the weekend as I'm sure I should get better results.

 

[siggy_7]

I bought this jig too, and have no complaints about the jig itself. However, I don't like the need to move the router inside the template with the guide bush, since any debris will cause the hole to be under-sized. As a result, I found I had to test each hole individually and re-cut whilst also making a lot of effort to keep the jig clean. I've now turned up a 37.1mm guide bush that snugly fits the jig, with the intention of using a trusted 20mm bit to cut the holes the next time I use it. I'll make sure the bush is concentric with the collet, but even if it isn't provided I'm careful to hold the router in the same orientation for every hole then it shouldn't make a difference.