Any tips for getting a good jointed edge on a router table? I'm struggling.

[scubadoo]

No matter what i do i always end up with a slightly concave joint and i can see the gap appear against the fence when i'm about halfway through. I'm using the Jessem Rout-R-Fence with the supplied aluminium shims on the outfeed, the Jessem stock guides and feather boards on the outfeed. Is that the right way to do it?

I set the outfeed to be in line with the cutter. What does a concave joint mean in terms of the cutter being too proud or not in line?
I know i could fine tune with a plane but I'd like to get it closer on the table if possible.

Any tips or can anyone see anything that could be causing issues?
Cheers
Dave

 

[Spectric]

I do not use a featherboard on the outfeed fence when the fences are offset. Is your fence set so the cutter is inline with the outfeed fence ?

 

[scubadoo]

I do not use a featherboard on the outfeed fence when the fences are offset. Is your fence set so the cutter is inline with the outfeed fence ?

Do you push it against the outfeed fence? Would you use the stock guides?

Yes the cutter is aligned with the outfeed fence - as close as I can get it. Just had a thought - a top bearing cutter should make it easier to align the fence to the bearing rather than guessing where the outer most bit of the cutter is?

 

[Spectric]

My trim cutters all have a top bearing which makes alignment to the outfeed fence much easier.

 

[scubadoo]

My trim cutters all have a top bearing which makes alignment to the outfeed fence much easier.

Thanks @Spectric.

Would you use any featherboards or the stock guides or just hands?

 

[peter-harrison]

I think it will be the relationship between the outfeed fence and the cutter. Using the bearing and a straight edge is easy but it does rely on the bearing being exactly the same diameter as the cutter which is not as common as you might think. If you use a straight edge on the outfeed fence and bring it up to the cutter, when you turn the cutter does it really engage with the straight edge or just kiss it? Or not touch it at all? What you want is the middle one of those options- anything else will cause problems.
The infeed fence is not important for this- all it does is set how much you take off with each pass.

 

[scubadoo]

I think it will be the relationship between the outfeed fence and the cutter. Using the bearing and a straight edge is easy but it does rely on the bearing being exactly the same diameter as the cutter which is not as common as you might think. If you use a straight edge on the outfeed fence and bring it up to the cutter, when you turn the cutter does it really engage with the straight edge or just kiss it? Or not touch it at all? What you want is the middle one of those options- anything else will cause problems.
The infeed fence is not important for this- all it does is set how much you take off with each pass.

Thanks Peter. I'm trying to set it up so that the cutter just kisses the straight edge as you suggest.

Just did a test joint and it's better but still slightly concave. Using a Jessem stock guide on the outfeed fence.

 

[toolsntat]

It may be you have the infeed fence out of line with the outfeed.
Does the gap also eventually appear on the infeed?

Those top rollers, do they toe in as they should?
Cheers, Andy

 

[scubadoo]

It may be you have the infeed fence out of line with the outfeed.
Does the gap also eventually appear on the infeed?

Those top rollers, do they toe in as they should?
Cheers, Andy

The outfeed fence is offset by the aluminium inserts that came with the fenceThe gap does not appear on the infeed fence. The rollers do toe in.

I'll check alignment of the outfeed fence to the infeed fence, thanks.

*edit* fences seem to be in alignment.

 

[Fitzroy]

I have had problems on by surface place with getting a concave of tapering cut, it's the same cut when I think about it and all about alignment of the cutting edge to the outfeed table. The way I do it in on the surface planer is adjust the outfeed table fractionally above the knives then when you try to push an edge through it will hang up on the outfeed table, I then drop the height until the work piece clears the outfeed, enabling me to get the outfeed height level with the cutting plane.

 

[Fitzroy]

I have had problems on by surface place with getting a concave of tapering cut, it's the same cut when I think about it and all about alignment of the cutting edge to the outfeed table. The way I do it in on the surface planer is adjust the outfeed table fractionally above the knives then when you try to push an edge through it will hang up on the outfeed table, I then drop the height until the work piece clears the outfeed, enabling me to get the outfeed height level with the cutting plane.

once you've made the initial cut on the leading edge of the work piece you can turn off the spinning flesh masher whilst you adjust the outfeed table.

 

[toolsntat]

*edit* fences seem to be in alignment.

Okay, you can do a little experimental adjustment to see if it changes things.
Pop a two fold of paper behind the infeed fence at the second fastener and see what difference you get, if any.
It's worth remembering that you are in fact using a surface planer and as with those the infeed and outfeed need perfect alignment.
EDIT looks like you have 3 fasteners..... so 0 behind 1, 1 behind 2 and 2 behind 3

Cheers, Andy

 

[scubadoo]

Okay, you can do a little experimental adjustment to see if it changes things.
Pop a two fold of paper behind the infeed fence at the second fastener and see what difference you get, if any.
It's worth remembering that you are in fact using a surface planer and as with those the infeed and outfeed need perfect alignment.
EDIT looks like you have 3 fasteners..... so 0 behind 1, 1 behind 2 and 2 behind 3

Cheers, Andy

Ok, just tried that and i end up with a slightly convex bump in the last 1/3 of the board

 

[recipio]

I wonder if the cutter is fractionally proud of the outfeed fence. You would reach a pivot point about half way through the cut as the cut now rides on the outfeed fence creating a miniscule gap at the infeed end. The rollers will force the piece on to the infeed side machining a tad too much timber. Just a thought and using a bearing for alignment with a steel rule should correct the problem. Of course you could win the lotto and buy a Jessem TA fence to make microadjustments.

 

[scubadoo]

EDIT looks like you have 3 fasteners..... so 0 behind 1, 1 behind 2 and 2 behind 3

Cheers, Andy

Just tried that and i get a gap at the leading edge.

When i removed the fence pieces i notice there were some fragments of phenolic from the fence edge and screw holes which may have been messing with the fence so I've sanding those flush.

 

[toolsntat]

Ok, just tried that and i end up with a slightly convex bump in the last 1/3 of the board

Try a pass without the first roller.
Cheers, Andy

 

[scubadoo]

IOf course you win the lotto and buy a Jessem TA fence to make microadjustments.

My micro adjustment is a tap with a deadblow hammer!

 

[scubadoo]

Try a pass without the first roller.
Cheers, Andy

do you mean the stock guide? at the moment i'm just using the one on the outfeed side.

 

[toolsntat]

Just tried that and i get a gap at the leading edge.

do you mean the stock guide? at the moment i'm just using the one on the outfeed side.

Yes, the wheeled guide .
A small adjustment of whole fence may have it about right ?

 

[johnnyb]

I usually think that operation is awkward to acheive tbh. perfect alignment is not easily arrived at.
if I can I ditch the commercial fence and just clamp a straight piece across both faces with a tiny opening for the cutter. then attach a known straight edge to the work someway. pass this across a fat cutter preferably a compression bit. tbh with a known straight edge the fence can be dispensed with altogether.