Router bit advice

[Russ59]

Please be gentle, I'm learning :lol:

I need to make a series of 10mm mortises, 30mm deep. I have already cut the tenons to 30mm
I thought I had a 10mm router bit but was mistaken #-o so I started drilling and cutting them by hand but I need the easier option :wink: I will be doing them on my router table.
I will go and buy a bit tomorrow but with my router only being a 1/4" shank, all the 10mm bits I can see on the net are 25.4mm long (a tad too short).
To get my depth with one of these bits (extra 5mm) can I have the bit sticking out of my router slightly? i.e not pushed all the way in.
Surely if its tightened well, which it should be anyway, it should suffice.
Or should I just trim 5mm off all my tenons?

Russ

 

[marcros]

The bit will be longer than that anyway- the 25.4mm is the length of the cutting part.

 

[James-1986]

The shank is smaller than the diameter of the cutter you are using so the only restriction you have is the 'plunging stroke' of the router and the length of the router bit I've got a 1/4" 10mm cutter from wealden which is 58mm long.

As a rule of thumb 3/4 of the shank should be in the collet, though I've had it hanging out further plenty of times. If you bore out a large amount of the waste with a drill it will be a lot less work for the router which is good practice when you're using small cutters and routers.

 

[Woodmonkey]

If it's a blind mortise I find it easier to use a plunge router with a fence rather than doing it on the router table. This way you can just do a series of plunge cuts along the mortise then a cleanup pass to finish.

 

[blackrodd]

If it's a blind mortise I find it easier to use a plunge router with a fence rather than doing it on the router table. This way you can just do a series of plunge cuts along the mortise then a cleanup pass to finish.

+1 for above, very much safer.
This should be in the router instruction booklet.
I have just measured a 1/4" bit and as previously posted, the bit is 55mm in total,
and the tungsten cutting part is 24mm, which should be ample in the collet.
You can always slip the collet on the bit, flush with the end and do the nut up tight and measure the
maximum projection with the router fully plunged and locked,
But always use the minimum of projection, as in you're handbook.

Regards Rodders

 

[andersonec]

Cut 10mm off your tennons...

Andy

 

[wcndave]

For a snug fit I recommend making the mortise first. Then you can take super fine shavings off rough tenons with hand tools to get a perfect custom fit.

 

[siggy_7]

If you bore out a large amount of the waste with a drill it will be a lot less work for the router which is good practice when you're using small cutters and routers.

This is good advice, particularly if using 1/4" shank cutters. I find it quicker to make a series of full depth plunge cuts with the router, as the fence/jig is already set up for the job, and then clean the mortice out with a side to side motion. Plunging to remove the majority of the wood first puts much less load on the router and the bit, it's the bearings and bending loads in the cutter that are generated by high lateral forces that cause problems.

 

[Steve Maskery]

For a snug fit I recommend making the mortise first.

+1
Ok, It's too late for you now, we know, but it might be something to bear in mind in the future.

 

[wcndave]

For a snug fit I recommend making the mortise first.

+1
Ok, It's too late for you now, we know, but it might be something to bear in mind in the future.

Ah, Steve, when I said "snug", what I really meant of course was a Goldilocks fit!

 

[Steve Maskery]

LOL!
And what's all this nonsense about keep taking a bit off until it is right, eh? Whatever happened to Right First Time Every Time?

 

[wcndave]

YOU plus one'd it!

now I know when you do it on bandsaw / table saw, you get it to within a few thou, and then take a shaving where needed!

you can take it off, you can't put it on again!

hence do the mortise first.

that way, I always get my mortise right. First time. Every time.

 

[Steve Maskery]

YOU plus one'd it!

LOL! I meant cutting the mortice before the tenon

now I know when you do it on bandsaw / table saw, you get it to within a few thou, and then take a shaving where needed!

Actually I don't...

But we are getting a bit OT we need to help him out here.

I think your best bet is to use your largest cutter that isn't too large, 8mm, say, or 3/8", whatever you have. Gradually rout to depth, then very carefully adjust the fence on your router or jig, depending on how you are cutting them, until you get to your 10mm width. Don't forget to make sure that you feed against the cutter direction, it's all too easy to climb-cut without meaning to.

 

[Russ59]

Thanks for all the advice chaps.
All sorted now and even though I did the tenons first they all fit as snug as a bug in a rug.

 

[Steve Maskery]

That's what we like to hear!
S

 

[wcndave]

Actually I don't...

Wow, you must have like, the ultimate jig or something!

 

[custard]

Please be gentle, I'm learning :lol:

I need to make a series of 10mm mortises, 30mm deep. I have already cut the tenons to 30mm
I thought I had a 10mm router bit but was mistaken #-o so I started drilling and cutting them by hand but I need the easier option :wink: I will be doing them on my router table.
I will go and buy a bit tomorrow but with my router only being a 1/4" shank, all the 10mm bits I can see on the net are 25.4mm long (a tad too short).
To get my depth with one of these bits (extra 5mm) can I have the bit sticking out of my router slightly? i.e not pushed all the way in.
Surely if its tightened well, which it should be anyway, it should suffice.
Or should I just trim 5mm off all my tenons?

Russ

Russ, for future reference a general principle in woodworking is "first cut the hole, then cut the thing that'll go into the hole", so most woodworkers would cut the mortice first, then they'd cut the tenon to fit. The reason it's done this way around is that tenons are easier to adjust than mortices.

On the shank of a router but you should see a scribed line, the idea is that this scribed line should be level with the top of the collet or inside the collet, the scribed line mustn't be outside the collet. That normally gives you the wiggle room you need, but if not the joint will be plenty strong at 25mm deep. But make sure you leave a gap of 3mm or so between the end of the tenon and the bottom of the mortice!

Another tip, if you're a beginner and there's a chance that your tenon might not be a perfect friction fit, then use Cascamite glue instead of PVA, Cascamite is more of a faff to mix up, but it gives you loads of open time to get the clamps on, and it's quite a bit better than PVA at filling small gaps.

Good luck!