Thread: Timber frame slot ideas and help

Hi,Probably a chain morticer is the easiest way,not a cheap bit of kit though.

what is the purpose of the slot? If just for pressure relief, a single drill hole may suffice. Have you considered laminating the frame? You could rout the slots before laminating? 4mm x 80mm deep x width is quite a challenge, making a 4mm mortise chisel might be quite a project.

Another option if you have a drill press may be a series of holes and then a drill with teeth (can't remember what they are called) worked along like you would a router, maybe even start with a router.

Thanks Mark! The chain mortiser is quite interesting, never seen anything like it before. Bit out of my price range though.

If you google wedding guest book drop box Thylacene you will see what I am trying to make. I am considering if a standard mortise machine would do the job. For those that have a mortise machine, what is the smallest width chisel that these machines use? And would they mortise 80mm deep?

If I could get a mortise bit even 6mm wide that might do the job, as I can mortise the slot, and I can take the extra 2mm out of the back of the frame and just sand 2mm off the back where the slot is to create the drop box. Maybe someone with a mortise machine might be able to help. Thanks guys!

I would think a spiral up or down cut router bit could do the trick. Just set stops at the relevant points on a router table, rout one side, then the other. Have a look at Carbitool's catalogue to see what length their 8mm cutters are.

Originally Posted by LGS

I would think a spiral up or down cut router bit could do the trick. Just set stops at the relevant points on a router table, rout one side, then the other. Have a look at Carbitool's catalogue to see what length their 8mm cutters are.

The slot needs to be 4mm, I don't think an 8mm bit will help...

I could possibly go up to 6 mm and section a bit out of the back, I might look into a mortise machine or drilling the bulk of it using a drill press and clean it up with a router.

Originally Posted by elanjacobs

The slot needs to be 4mm, I don't think an 8mm bit will help...

Thanks for that. How silly of me!

Have a look at Page 5 on the Carbitool wood router bit catalogue and you'll find this:

TSRW 5 Spiral cutter.
Cut diameter 3.96mm
Cut length 16mm.
Bit length 57.15mm.

Originally Posted by dlannetts

I could possibly go up to 6 mm and section a bit out of the back, I might look into a mortise machine or drilling the bulk of it using a drill press and clean it up with a router.

How are you going to get your router bit 40mm into the cut? They don't make small diameter bits with a cutting edge that long.

Originally Posted by LGS

Have a look at Page 5 on the Carbitool wood router bit catalogue and you'll find this:

TSRW 5 Spiral cutter.
Cut diameter 3.96mm
Cut length 16mm.
Bit length 57.15mm.

DO NOT try to use that to get to 40mm deep. EVER. Regardless of how many passes you do it in.
First, you need AT LEAST 20mm of the shank in the collet. Second, given that the cutting edge is only 16 mm, the rest is solid carbide which will be rubbing on any timber above the flutes at 20,000+ rpm. In such a small bit the amount of heat generated could well cause it to break, any wobble with that length of unsupported 4mm carbide would probably cause it to snap as well.

Maybe go old school. Drill it out, then use chisels.

1/4" upcut spiral bit with a 1" cutting length and overall length of 2 1/2", 1/4" shank. Hold 20mm of the bit in the router collet leaving ~43mm exposed. Cut your first slot ~41mm deep from one side, and then go in from the other side to remove the remaining ~39mm.

You will need to insert the cutter shank into the fresh cut slot by about 15mm which can heat the bit pretty fast as Elan suggests, but since you are doing this by hand the slot will be wider than 1/4" due to your arms/shoulders not being anywhere near rigid enough to produce a 1/4" slot using a 1/4" cutter, so it should be all good without any burning. You might snap the bit which is no big deal, its not as if they fly across the room when that happens...it just gets stuck in the slot.

I went to maccas to get dinner and i realised there is another way that you can which is fairly painless and gives you your original 4mm wide slot.

In the slotted piece of timber, run a trench about 70mm deep all the way along the length using a tablesaw with a 4mm kerf blade or in a couple of passes with a thinner blade. Then rout the slot from the external face to be 4mm wide. you only need to rout 10mm deep so it should be nice n easy. Then glue in two fillets of timber 70mm wide x 4mm thick to fill in the extra slot.

see image.

wedding.jpg

Brilliant idea, I'd give you 2 likes if I could

Originally Posted by elanjacobs

How are you going to get your router bit 40mm into the cut? They don't make small diameter bits with a cutting edge that long.


DO NOT try to use that to get to 40mm deep. EVER. Regardless of how many passes you do it in.
First, you need AT LEAST 20mm of the shank in the collet. Second, given that the cutting edge is only 16 mm, the rest is solid carbide which will be rubbing on any timber above the flutes at 20,000+ rpm. In such a small bit the amount of heat generated could well cause it to break, any wobble with that length of unsupported 4mm carbide would probably cause it to snap as well.

You could not get any further than 16mm as that is the depth of the cutter. The shaft would not permit you to go any further. If you cut with the upcut in to a depth of 16mm OR LESS (i.e. Multiple passes with the cutter), then you can use a drill press to to finish the through cut and possibly sand to finish. I have not at any point suggested any practise involving endangering the work piece or more importantly the user!!! Is that clear?