Newbie to Jigs - Router guide bush with collar problem.

[Skeety]

Hi All,

I'm fairly new to routing and have mainly used it in the table, for a garden table restoration i'm doing I needed to remove an old mortice and insert a repair piece in order to give me a secure fixing for a Domino prior to re-assembly.

The ideal solution seemed to be a guide bush and collar to cut out the bad wood and make the insert along with the repair piece.

I made my jig and then had to change it to allow for the offset of the collar (newbie mistake) but tried it on a bit of MDF before cutting the repair holes in the Teak table top. I ended up with a perfect cutout in the MDF with nice rounded corners but the infill piece once the collar was removed has square edges obviously as it was using the internal face of the cutter.

The infill piece is perfect apart it has square edges so doesn't fit perfectly. I'm happy to sand the repair pieces to fit as they won't be seen but wondering how to get a perfect infill that doesn't need sanding and fettling if possible.

I'm using a Trend T11 with a 10mm cutter, 20mm guide bush and a 20-40mm collar. I'll try and add some pics below.

Many thanks for any advice you can offer

Cheers,

Jon.

 

[Skeety]

https://www.dropbox.com/s/dqd7s5xqoah5m ... .02.56.jpg

https://www.dropbox.com/s/5mltdgy25ac4r ... .02.35.jpg

 

[RobinBHM]

If your cutter is 10mm you have a 5mm radius in the corners. Your jig needs to have round corners with a radius larger than this by the same amount as your offset. (I think!!)

 

[woodbrains]

Hello,

Make your template with radiused corners, at least as big as the largest guide collar. You will then rout a recess with round corners and your patch will fit in exactly. It is not the radius of the cutter you need worry about, it is the radius of the collars, bushes. I make patches for covering large Knot holes like this, though use a smaller bush/collar set, in my case 20/10 with a 5 mm cutter.

Mike.

 

[deema]

Just a thought, why not simply cut out a patch, place I top of the table in place, use a marking knife to outline, saw very close to the knife line the piece out and then trim back with a chisel? It should take less time than making the jig?

If I've misunderstood, and your inserting a piece, the routine is the same apart from cutting out the section. After scribing around the patch, use your router to remove the majority of the waste keeping inside the scribed line.finish off with a chisel. Again, should be quicker than making the jig.

 

[custard]

Just a thought, why not simply cut out a patch, place I top of the table in place, use a marking knife to outline, saw very close to the knife line the piece out and then trim back with a chisel? It should take less time than making the jig?

If I've misunderstood, and your inserting a piece, the routine is the same apart from cutting out the section. After scribing around the patch, use your router to remove the majority of the waste keeping inside the scribed line.finish off with a chisel. Again, should be quicker than making the jig.

+1

That's what I'd do. The problem with guide bushes is they make you think you're engaged in wood engineering down to tenths of a thou precision. But unfortunately guide bushes are rarely anywhere near that precise, they're often not perfectly round, they're not fitted concentric to the bit, the router suffers some run out, the bit isn't exactly the diameter it's advertised as being, or the router bit isn't perpendicular to the base, etc, etc. By chucking money and time at the problem you can overcome these, but why bother? Using the infill as a template and scribing around it will give you an excellent fit in a fraction of the time.

 

[woodbrains]

Hello,

For the odd patch, then I would not bother with a router at all. But for repetition, I think they have a place. A little lack of concentricity is easily overcome by simply orientating the router consistently. In other words, do not rotate the router whilst using it in the template, keep the front facing you at all times and any runout will not be a problem. This is not hard to achieve in practice and is good form in general router use.

However, I do think that Domino jointers are less useful, in fact, unless in a production environment. I think the price of these tools is only justifiable in commercial situations. For a small job, handwork is likely the most efficient for both patching and morticing. Since routers are almost ubiquitous, they could be used for both patching and morticing, so why the Dominos at all?

Mike.

 

[sometimewoodworker]

However, I do think that Domino jointers are less useful, in fact, unless in a production environment. I think the price of these tools is only justifiable in commercial situations. For a small job, handwork is likely the most efficient for both patching and morticing. Since routers are almost ubiquitous, they could be used for both patching and morticing, so why the Dominos at all?
Mike.

If you had a Domino I doubt that you would be asking the question. While you certainly can do anything a Domino can with a router and jigs. The time you will spend and the opportunity for mistakes is much greater.

I have no interest in doing by hand the tasks that my Domino does, so without it I wouldn't be making the things I do. When I was at school I did cut mortices by hand, and that was enough for me to know that I didn't enjoy the task. So now I have mortice joints in my items and enjoy the process of making them. For me that is justification enough.