Stupid question on guide bush offset

[ireland]

I have a hinge jig that requires a 16mm guide bush and a 12mm bit, Festool don't make a 16mm bush but they do a 17mm so my stupid question is what bit would I use with that? I think 13mm am I right?

 

[nickao]

That seems correct to me off the top of my head. Test it out on scrap anyway to make sure. My first thought was 12.5 mm, but I do think 13mm is correct.

Nick

 

[nickao]

No question is a stupid, I always get mixed up when using the bushings unless I draw it out.

Nickao

 

[ireland]

Thanks Nickao

 

[tangoack]

1/2 major diameter minus 1/2 minor diameter= offset

 

[Jim Becker]

Where you may get some contention is at the corners since the 13mm cutter has a larger radius than the 12mm specified. It's not just about offset...

 

[woodshopdemos]

Jims right, but if you are having to use a chisel to square corners, then this should not be a problem. On the other hand, if you are using hinges with rounded corners, they probably are of the lesser diameter and not an easy chisel job. A 12mm gouge would do it it but at that point, it will be easier to find the correct adapter and router bit.

 

[ireland]

Thanks Guys,

I square the corners up with a corner chisel.
1/2 of 16 = 8
1/2 of 12 = 6
8 - 6 = 2
but surley the offset is 4 ?
1/2 of 17 = 8.5
1/2 of 13 = 6.5
8.5 - 6.5 = 2
Ah I get it now sorry

 

[Troll]

I think you are using a Trend hinge jig, am I right?  I have exactly the same set up with the Festool router OF 1010 and 17mm guide bush.  All you need to do is to increase the spacing on the jig by 1mm - If I remember correct Trend gives you a 4mm spacer which you use in conjunction with the actual hinge to set up the jig.  I ditched this and use a 5mm spacer (I use a 5mm drill bit) to compensate for the 1mm larger guide bush.  Set up works absolutely fine and has done for a couple of years.

Changing the router bit might be more difficult as the jig uses a special reach router bit.

As an alternative you can use a Trend Unibase which will fix to the Festool Router allowing any Trend guide bush to be fitted.

Troll

 

[ireland]

Thanks Troll

I never even tought of that and yes its the trend jig. I ordered a base of trend about 3 months ago, it has to be drilled and they still haven't done it, nor confirmed when it will be done. I have a unibase on a diffierent router and I don't like it, when you get one drilled specialy, the edge of the base is the same distance to the edge of the bit all round.