Router non concentric guide bush allowance

[Secret_Sipper]

Due to learning how to use one and needing g one for the project In undertaking, rather than buying a large expensive unit I opted for a more DIY approach until I get more experienced. Yes I bought a lidl pof 1200 router.
Having got this a Christmas from my parents I've only just got round to trying it out.
I'm an engineer by trade so thought I'd make sure it was concentric to the spindle.
I put a square up against the bush and base then measured from the spindle edge to the square in 4 corners.
Using a Vernier calliper I got 2 sides at 7mm and 2 sides at 6.5mm.
To look at it, it does look slightly off but I don't know if that's just a slight optical illusion, hence measuring it.

Would you say that's acceptable given its price? And in a sense, I could mark the sides the same and only use these to cut with. I couldn't tell you what's at fault but I don't think it's the guide bush.

Cheers

 

[big-all]

as an aside the last time i saw them on sale they where metric as in 12/6mm rather than imperial 1/4 1/2 inch
what uses are you planning to use the router for ??
apart from worktops and signs i never use guide bushes most applications use a bearing fence or strait edge

 

[Secret_Sipper]

They are advertised as metric but with the collets they will make up the difference. 12.7mm = 1/2 6.3 = 1/4
At the moment I'm just learning and used 6mm hardboard I have left over from the cupboard back I took out to put the guide bush up against on the MDF template I'm making.
I've already bought a trend template profiler 1/4 but haven't used it just yet.
If I use it for anything else, it will be a bonus

 

[big-all]

to be honest on most applications 0.5mm wont make any difference
you can probably make it more accurate by enlarging/elongating the holes
it may be worth trying to plunge unevenly or differently to see if it effects the plunged cutter position

 

[foxhole]

You haven't told us the price?

 

[big-all]

£50 if i remember rightly although i think the last time they where£40

 

[Secret_Sipper]

It was technically a Christmas present but the only reason why I know the price is because she asked me what I wanted!
It was £29.99 last November so I couldn't justify spending 89 quid on the erbauer ones at screwfix or even a smaller Bosch/Makita palm routers.
To put it into perspective the profiler bit was £15

 

[big-all]

at 1200w you need to treat it as a 1/4" that can do heavy duty or a 1/2" router that can only do lighter duty as in 50% more passes than recommended with a 1/2" router or if a cutter needs to use one pass like a raised panel or door frame cutter then its under powered so cant be used

 

[Secret_Sipper]

Excatly

Im under no illusion it's to learn with only. If I use it more than I think I will. I'll actually buy one that is heavier duty than the lidl cheapo
For the MDF I've been using the 5mm step gauge but I think whilst cutting the oak, I'll resort to smaller cuts

 

[Deleted member 174758]

They are advertised as metric but with the collets they will make up the difference. 12.7mm = 1/2 6.3 = 1/4

OH NO IT DOESN'T! A 12mm collet simply will not accommodate a 1/2in (12.7mm) shank router cutter without deformation, similarly a 6mm collet won't accommodate a 1/4in (6.35mm) cutter shank - standard shank sizes on British cutters are 1/2in and 1/4in - European standards are 6, 8 and 12mm in the main. Go the other way and many cheaper collets don't have enough slits to ensure that they grip an undersize cutter shank adequately and without inducing run-out (which in turn causes vibration), so a 1/4in ccollet won't grip a 6mm shank cutter properly and I for one don't want to have a cutter ejecting itself in my vicinity at 24,000rpm. ER32 collets on engineering stuff are large enough to have a sufficient number of slits to give flexibility and therefore can accommodate a range of sizes - a router collet with 3 or 4 slits isn't that forgiving. That's the difference

Guide bush mountings should be concentric with the router collet, but often aren't on lower cost routers. the solution is to get/make a cone-shaped centring mandrel, like this one from Wealden Tool:

and use that to centre the guide bush before fixing it. If needs be the guide bush can be fixed in place with domed-head cap screws (if space pemits - this works on my DW625). The cutter is inserted afterwards. 0.5mm may not sound much but it starts to be a problem when you are fitting certain hardware useing jig, guide bush and cutter, e.g. door lock face plates, hinges, flush bolts, etc

 

[big-all]

just shows you i should have read it fully i seen that answer as it comes with 1/2 and 1/4 inch collets and didnt notice it was just the 6 and 12mm with the expectation it would deform to take a larger cutter which off course it wont

 

[Secret_Sipper]

Looking back at that I'd probably agree with the statement for the 1/2 collets as it's quite large jump up between the metric and imperial equivalent, so apologies and well picked up on.

For the 1/4, I'm not so sure 0.35mm (0.014") will be an issue but I take your comments on board being far more experienced than myself.
Luckily for me, the router I'm using is a 6/8mm collet size and I'll give the 1/4 cutter a go.
The guide bush assembly are on counter sunk pozi screws. On mine, I don't think I'd get away with putting button heads in but it's a tight call. Unless I swapped the base with something alitte thicker?

 

[big-all]

i personally would look to use a say 3.5mm drill bit or whatever the radius is and drill the corners this off course will need a seperate purpose built jig
how do you plan to affix the jig for the router ??
it will have to be well affixed to compensate for the router weight and sideways "drag" off the cutter

you also have to keep in mind the depth off the lip on the guide bush as the jig thickness will will have to be as thick as the visible lip

 

[Secret_Sipper]

Yea. The depth still has to be relative to the guide bush lip...

Hmm. might have to make the button heads fit after all!

Cheers

 

[Deleted member 174758]

Almost all woodworking router collets are the same in one respect: the lower end has slits to allow a small amount of undersize variation in the diameter of the cutter shank whilst the top end has no slits and is therefore incompressible. With a 6mm hole drilled through the middle +/- 0.05mm you normally can't get a 6.35mm shank into the hole (bearing in mind that the shank needs to be fully held within the collet). Also worth considering that collets in most engineering kit is being run at a few hundred to maybe 3000 or 4000rpm - woodworking routers spin at 22 to 30k rpm

If nothing else you can always make up a thicker sub base in thicker Tufnol, polycarbonate or acrylic - even 12mm MDF will often do for a one-off job (or for that matter 12mm h/w ply)