I'm having some issues trying to get stopped slots cut on a router table

[torn lodge]

I'm trying to cut some half inch wide blind slots into some 1x1x6 pieces of wood for a project and the bit keeps either tearing the wood apart, shattering the black walnut, or trying to rip the piece out of my hand. I got ONE to be almost perfect but I have no clue what was special about that attempt.

I've attached some pics of attempts and I'm using a half inch diameter round nose bit.

Lmk if you need any more info. This is really starting to frustrate me as I'm still learning alot about this craft

[gray umbra]

Well, I have several suggestions/questions

[torn lodge]

Fire away. Idk how much longer I can hide the fact I have no clue what i'm doing lol

[gray umbra]

Questions
Which of those was first?
How much experience with routers do you have?
Is that a yonico bit?
At any point were there flames or did you stop at searing?
How deep of a pass are you taking at once?
How are you starting and stopping each cut?
Are you using the appropriate speed for that bit?

[torn lodge]

First wat the very top one and that was with a very old plunge bit that came with the router I bought. The first with the round bit is the one second from top.

I'm just starting out so not too much.

This is the set I bought: https://www.amazon.com/dp/B07ZNHB4ZN?ref=ppx_yo2ov_dt_b_fed_asin_title

There was no fire and honestly very little smoke that I noticed. There was some with the old but but the new ones not really

Everything you see is all 1 pass. It seems to be as low as I can get the bit to go with my current setup.

So the first few I tried to press down and also slide forward to give it kinda a ramp in. On the very bottom one and the middle one I very gently pressed it against the bit in one place and let it settle itself

My router only has 1 speed

[gray umbra]

Comments
If that bit was ever useful, it’s not currently. The burning you’re experiencing is self defeating as the more it happens the more likely it is to happen faster as you’re dulling the bit directly but more importantly making a mess of it with burned wood, carbon and pitch.

Routers move fast and will punish poor forms (or bits….or materials) just as fast.

In a fully enclosed cut like this the bit is working more than twice as hard both cutters are always engaged. This increases heat and wear while reducing margin if error.

Sharp bits are important and Yonico is garbage.

You may find it much easier (after addressing the bit, speed, feed rate and depth) to do these cuts on a wider panel and then ripping the finished pieces off. The larger panel will easier to control.

Lastly grain direction is very important t to both stability I cut and in its resulting quality

I would be sincerely afraid to spin one of those bits at all, much less in a 40mm(?) single pass

I’m legitimately amazed they didn’t explode

[torn lodge]

You mention Yonico but my googling says that's a brand. Are you referring to a brand of bits or a style?

[gray umbra]

The maximum depth of cut for a router bit is usually about half its diameter and that goes down as the diameter goes up

[gray umbra]

Yep, yonico isn’t a (potentially dated) Amazon house brand

Generally spinning something 20,000 times per minute is best reserved for things that cross the 3$ each mark

Amana, white side, even Freud in a pinch

Even if you choose to continue with those bits, which I thoroughly recommend against, you need to be cutting maybe a fifth as deep per pass (or so)

[torn lodge]

So in summary:

Bit is shot. I should replace it. Would I have any different luck with a different shaped bit or can i stick with the rounded (and what brand do you reccomend?)

You mention grain direction is important and I just noticed that the ones thay didn't explode are the ones where I was cutting parallel to the grain. Lesson learned there I guess. I wonder if there's where alot of my problems are.

[gray umbra]

Your first problem is pass depth, then bit quality then grain direction

IMO

[torn lodge]

ok. I gotta figure out how to get my bit lower. It's already bottomed out in the chuck so i may need to get creative

thanks for the info!

[gray umbra]

The router (I hope) will have a depth setting capacity

[torn lodge]

Yea. I just need to shim my table up to give it some clearance to drop down. Would you like to see my abomination of a router setup?

[gray umbra]

I’ve had 3 bourbons so sure

[torn lodge]

aight one sec

So the disclaimer is i'm in college and trying to do this on a shoestring budget... The router table I got for free from some legend I was buying wood offcuts from and I got the craftsman router in an estate sale. I had some 3mm delrin from an old commission so I laser cut an adapter plate that screws onto the router and because delrin is magin I was able to tap threads right into it to screw everything into the table. It honestly feels really stable. It doesn't try to shake itself away from me in fact i don't feel any vibrations at all

[gray umbra]

So like, plywood

But that looks fine…ish

[torn lodge]

if it'll get the job done and it's safe I'm gonna roll with it

[gray umbra]

The router and table is substantially safer than your technique and bit selection

Those nickel bits are legitimate risks of exploding

I am sincerely surprised they held up in a cut that deep

[torn lodge]

fair enough. By technique do you mean depth of cut? Or is there something is in that respect I should work on?

[gray umbra]

The depth particularly is immediately evident

From the “wiggles” in your cuts I think you’re probably not secure either and need to correct those things very quickly or there is a very real risk of injury

And a not insignificant likelihood of that injury being life changing

[torn lodge]

the fence is locked down tight. I'm pressing against the fence and sliding it along being careful not to go too fast or stop and cause burn. So top pressure and side pressure.

[gray umbra]

But you’re pressing with your hand, yes?

Router catches at an inch deep can be….violent

[torn lodge]

Yes. I've been brainstorming a bit some form of workholding that'll give me the control I need. As you can tell I don't have much in the form of existing shop infrastructure to base a solution on rn

[gray umbra]

Just takes one time of your hand going into that bit (or the bit exploding into your face) to give you some very lasting memories

They’re called featherboards

Woodworking is solved science, it requires more research than innovation by orders of magnitude

[torn lodge]

makses sense. So the featherboards press it to the fence and then I can use a push stick to guide it through? Wouldn't it get launched out without top pressure of some sort?

[gray umbra]

Featherboards can be oriented to provide both

Your hands can also be appropriate too, just depends what you’re doing

My earlier estimation of your issues stands, those issues are compounding and addressing them may or may not accentuate further issues

But those are glaring enough that it makes further assessment after the fact from two pictures nearly impossible

[torn lodge]

okay. come morning I'm gonna shim up the table to drop the bit depth down and spec out something less....explodey to mount in the chuck. Thanks!

[gray umbra]

Godspeed

[torn lodge]

i'm sure I'll be back with more questions as this goes on. I'm so far into this project and loving the outcome so much I refuse to let this stop me

[gray umbra]

Ping me I will stop following this thread in about 4 minutes

[slow grotto]

Two quick things. You shouldn’t completely bottom out your bit in the router. There’s generally a max depth line on the shank that’s several mm from where the cutter starts and you want to make sure you don’t go past that. Second, you may have missed it, but there was a comment about the router base having depth adjustment and you replied about shimming the table. This shouldn’t be necessary. You should be able to slide the spindle of the router up and down in the router base. Here’s a really crappy video where they demo it, sorry it was the only one I could find that appears to use your router. 2:08 in the video. https://m.youtube.com/watch?v=_9MHbghiCbo&t=2m8s apologies if you already tried adjusting the router depth in the base and this is still not doing it, but there’s no way a bit should stick out that far and not be able to pull it back in.

[torn lodge]

Yea the router has depth adjustment but it's so tall it's almost taller than the table itself. So if I want to lower the depth I need to give the router more room to drop down if that makes sense

[torn lodge]

@gray umbra if I installed feather boards wouldn't that prohibit me from lowering the workpiece onto the bit like I'd need to do to make a blind slot?

[gray umbra]

it would limit it, yes

[torn lodge]

@gray umbra

I got better tooling and with splitting the operation into 4 shallower passes I got good results. However given how many of these I wanna make I wanna speed up the processes.

If I used a forstner bit on my drill press to remove the bulk of the material could I do one deep pass on the router table to clean up the edges of the holes into a contiguous slot or would that still be too much load on the bit?

[gray umbra]

if the forstner removes enough of the primary material, yes

[torn lodge]

Thanks. I'll order one and give it a go

[gray umbra]

1/4" less than your final width cut to 1/8 above final depth will do it

that leave 1/8 on all cuts