Flattening a slab and routing groove

[qwertyu]

So as many of you guys have helped me with my current project - a waterfall edged coffee table, I am planning next project!

I have a slab of southern mahogany and wish to make a river art square - like this:
river art square / Greg Klassen (http://www.gregklassen.com/product/river-art-square)

The slab is pretty flat but would like to know what is the best router trip if I needed to flatten it.

Also, what tip should I use to do the groove which the glass sits in - I suppose it will be a flush trip bit, but is there a special/specific type which would be best?

Lastly, if I wanted to make a wide area for the glass to sit in, one which is wider than the base of the router, how do I keep it flat?

Eg like the first pic in this link
10' black walnut river dining table / Greg Klassen (http://www.gregklassen.com/product/10-black-walnut-river-dining-table)

[Fumbler]

If it were me, I would make an MDF template of the shape ie following the contour of the river, but not as jagged, slow long curves but still enough to get the effect. I'd use a broad based rebate cutter something similar to this https://www.amanatool.com/pub/media/catalog/product//r/c/rc-2257_3.jpg (https://www.google.com.au/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&ved=2ahUKEwi0gdSXs4raAhXGerwKHWvrAFEQjRx6BAgAEAU&url=https%3A%2F%2Fwww.amanatool.com%2Frc-2257-insert-carbide-spoilboard-surfacing-rabbeting-flycutter-slab-leveler-surface-planer-2-1-2-dia-x-1-2-x-1-2-inch-shank-router-bit.html&psig=AOvVaw2800h8G47e0a1IELWiR0BT&ust=1522167754086649)

an use the router freehand against the template. there are a few bearing-less rebate cutters out there and the wider the bit the better the lip for the glass to sit on.

hope this helps and was what you were asking.

[ian]

So as many of you guys have helped me with my current project - a waterfall edged coffee table, I am planning next project!

I have a slab of southern mahogany and wish to make a river art square - like this:
river art square / Greg Klassen (http://www.gregklassen.com/product/river-art-square)

The slab is pretty flat but would like to know what is the best router trip if I needed to flatten it.I suggest a router sled -- I'm sure there are examples and build instructions on this site. Just be sure that your work surface is flat, and you wedge the slab so it doesn't rock while you are flattening it.
also be sure that your slab is fully dry


Also, what tip should I use to do the groove which the glass sits in - I suppose it will be a flush trip bit, but is there a special/specific type which would be best?I suggest that you make a template using either hardboard or 6 mm MDF. The curves on the template need to approximate the curve you are following and be smooth. Then use a top bearing rebate or morticing bit.
Only because I have downloaded a copy of the complete CMT catalog, the stock number of suggested bits would be
Morticing bits
http://www.mikestools.com/CMT-Cutting-Tools/CMT_801.127.11Bjpg.jpg
801.190.11B (1/4" shank, 19mm dia, 19mm cutting depth),
801.818.11B (1/2" shank, 31.7mm dia, 5.7mm depth),
801.817.11B (1/2" shank, 31.7mm dia, 12.7 mm depth)

Dado and planer bit
https://cdn3.volusion.com/kmj3v.qwgs5/v/vspfiles/photos/CMT-852.001.11B-2.jpg?1521455394
852.001.11B -- 1/4" shank, 19mm dia, 9.5mm cutting depth
852.501.11B -- 1/2" shank, 19mm dia, 9.5mm cutting depth
852.502.11B -- 1/2" shank, 25,4mm dia, 9.5mm cutting depth
852.503.11B -- 1/2" shank, 31,7mm dia, 15,8mm cutting depth
852.504.11B -- 1/2" shank, 38,1mm dia, 15,8mm cutting depth


Lastly, if I wanted to make a wide area for the glass to sit in, one which is wider than the base of the router, how do I keep it flat?my suggestion is that you attach your router to a false base plate that is big enough to span the entire gap with length to spare.

[qwertyu]

Thanks guys. What brand of router bit should I get? Would like quality/clean cuts. I see the Amanatec has carbide bit which can be rotated when blunt? (like spiral cutter head of planner?)

[ian]

This test by Canadian Woodworking Magazine might help https://www.canadianwoodworking.com/tools/router-bit-comparison

Big caveat.
with a specialty bit like you will likely use for the rebate, you are very unlikely to cut anywhere near the equivalent of 320' (105 m) of MDF. This means that a bit that is good out of the box is likely to still be sharp years later.
Also, the Canadian test didn't include Australia's Carb-I-tool bits which are every bit as good as US or European made bits.

[qwertyu]

Thanks Ian. I'm downloading the carbitool catalog now. I see on that canadian woodworking site that CMT kinda sucks so I will avoid them. Where would one buy Freud? I might look through that catalog too. Is there anywhere else other than total tools to buy carbitool? I see that there head office is SE Melb, close to me.

Im also thinking about how I will attach the glass to the timber. Having a bit of an undercut for mechanical retention seems like a good idea, and I could probably do it with a dovetail bit with a bearing on top? On pg 13 what do you guys think about the "T cut" or the "gifkins" bit?
CARB-I-TOOL - Router Bit and Accessories Catalogue - NOVEMBER 2015 (http://envirocatalogue.com.au/Carbitool_Website_2012/Router_Bit/files/assets/basic-html/index.html#13)

That would mean I will need to use 2 bits, which might mean it will be difficult to get a flat surface after routing? Does it seem too risky?

What are people's thoughts on type of glue I should use for glass and to timber? just an epoxy? Any thoughts on how to do it so its not so visible? Another option might be silicon - since its flexible it can account for wood movement?

[ian]

the glue question was discussed in a recent thread

I would advise against using a dovetail bit to undercut the top in an attempt to retain the glass.
the appropriate bit would be a slot cutter, followed by the rebate cutter -- but I note the piece you are emulating doesn't appear to have an undercut, and the table definitely is not undercut.
Again, only because I have a downloaded copy of the CMT catalog which makes searching much easier, the sort of bit I'm thinking of is item number 823.332.11B -- 1/2" shank, 47.6 mm dia, 3.2 mm wide slot.

I think you are going to need at least two bits.
A surface planer bit for the flattening and a either a bearing guided rebate or dado bit, or a similar bit guided by a copy ring.


BTW, what make and model of router do you have?

[artme]

Just my two cents worth: If you have some scraps or even other good pieces of the timber you are using, do some test cuts to
judge the right feed rate for the bit. Be a shame to ruin good timber.

[Fumbler]

I would avoid a slot or undercut, as the timber can and may move with the change in humidity etc, if the glass is trapped, it will don1 of 2 things, 1. The glass will shatter or crack, and 2. If u used toughened glass then it may not crack but split the wood along the top of the slot, which you don't want.

just some food for thought. I'd recommend exactly as it was shown, solid base with the 2 sides of the river secured fast, then just lay the glass in the the river. It'll also make cleaning easier!!

[qwertyu]

the glue question was discussed in a recent thread

I would advise against using a dovetail bit to undercut the top in an attempt to retain the glass.
the appropriate bit would be a slot cutter, followed by the rebate cutter -- but I note the piece you are emulating doesn't appear to have an undercut, and the table definitely is not undercut.
Again, only because I have a downloaded copy of the CMT catalog which makes searching much easier, the sort of bit I'm thinking of is item number 823.332.11B -- 1/2" shank, 47.6 mm dia, 3.2 mm wide slot.

I think you are going to need at least two bits.
A surface planer bit for the flattening and a either a bearing guided rebate or dado bit, or a similar bit guided by a copy ring.


BTW, what make and model of router do you have?

Thanks. I dont have the exact model but its a plunge router and made by Makita. Its an older router. If its no good I'll get a new one. I notice there arent many options for routers - Festool, Makita and Bosch? Are other ones worth looking at?


Just my two cents worth: If you have some scraps or even other good pieces of the timber you are using, do some test cuts to
judge the right feed rate for the bit. Be a shame to ruin good timber.

Ill deff practice first!


I would avoid a slot or undercut, as the timber can and may move with the change in humidity etc, if the glass is trapped, it will don1 of 2 things, 1. The glass will shatter or crack, and 2. If u used toughened glass then it may not crack but split the wood along the top of the slot, which you don't want.

just some food for thought. I'd recommend exactly as it was shown, solid base with the 2 sides of the river secured fast, then just lay the glass in the the river. It'll also make cleaning easier!!

Im not actually make a table :)

[ian]

Im also thinking about how I will attach the glass to the timber. Having a bit of an undercut for mechanical retention seems like a good idea, and I could probably do it with a dovetail bit with a bearing on top?


I would advise against using a dovetail bit to undercut the top in an attempt to retain the glass.
the appropriate bit would be a slot cutter, followed by the rebate cutter -- but I note the piece you are emulating doesn't appear to have an undercut, and the table definitely is not undercut.
Again, only because I have a downloaded copy of the CMT catalog which makes searching much easier, the sort of bit I'm thinking of is item number 823.332.11B -- 1/2" shank, 47.6 mm dia, 3.2 mm wide slot.

although I suggested a slot cutting bit if you want to create an undercut to retain the glass, I've subsequently had a good look at the photos in the link you posted in post #1. I'm sure I can see the edge of the glass in each photo, meaning that the originals are not undercut.

as Fumbler advises, best to stay away from a mechanical connection

[Fumbler]

Im not actually make a table :)

So, if your not making a table, or table top, what are you making?

with all said before maybe you can route the retainer groove a few mm wider than the glass, then use clear silicone along the edge wall of the cavity to retain the glass, and with the additional space any warping due to humidity may not spilt either the wood or the glass.

out of curiosity, how big are we talking here slab wise?

[ian]

qwertyu wants to make something like this
https://images.bigcartel.com/product_images/189760388/FullSizeRender.jpg?auto=format&fit=max&h=1000&w=1000
river art square / Greg Klassen (http://www.gregklassen.com/product/river-art-square)

I'm sure the glue issue has been answered recently

[ian]

I'm sure the glue issue has been answered recently
it was http://www.woodworkforums.com/f198/help-219924?highlight=glass

[qwertyu]

Thanks guys.

Had a look at the Makita router - it is the 3600BR. 1/2" 1500W unit. Its pretty old/beat up but still works. The plunging mechanism isn't so smooth but I dont think I will be doing any plunging.

I think for router bits I will go with the carbitool surface planer
https://www.google.com.au/search?q=carbitool+tss+13+1%2F2&ie=utf-8&oe=utf-8&client=firefox-b-ab&gfe_rd=cr&dcr=0&ei=aFe7WpPFEqnM8gem6r7wCA

and the carbitool inverted flush
https://www.totaltools.com.au/42708-carbitool-tct-inverted-flush-trim-bit-1-2-dia-1-4-shank-t8216b

You guys think they will be suitable? is 2 cutter heads for the inverted flush enough (ie will it be a rough cut?)

Only issue is that the inverted flush has 1/4" shank - I dont think I have an adapter. I also have a makita palm router - are they usually 1/4"? (dont have the model number right now)

In terms of glue - I looked at that thread - clear epoxy seems to be the suggestion. you guys think I should just glue the edge of the glass to the wood (glass might be 6mm think)? Or the entire surface which is sitting to the glass (more risk of air bubbles)

The slab is almost 2.Xm long. But I dont plan on using the entire slab, just a portion to get a triptych.

[bueller]

If you can get to a Timbecon they have a 1/4” to 1/2” collet adaptor for $9, just picked one up a couple of minutes ago for a project I’m working on.

[qwertyu]

Ah cool - cant get the timbecon but I notice that bunnings has one too:
https://www.bunnings.com.au/craftmaster-6-4mm-collet-router-bit-to-suit-12-7mm-shaft-router_p6372144

[elanjacobs]

I think for router bits I will go with the carbitool surface planer
https://www.google.com.au/search?q=carbitool+tss+13+1%2F2&ie=utf-8&oe=utf-8&client=firefox-b-ab&gfe_rd=cr&dcr=0&ei=aFe7WpPFEqnM8gem6r7wCA
I would strongly advise against a 6-flute bit unless you can turn the speed waaay down on your router and/or can move VERY fast.

There was a thread here a while ago with someone who couldn't understand why it was burning everything. Basically it's spinning so fast that it's scraping the timber, not cutting it. Scraping generates a lot of heat and heat destroys cutting edges very quickly.

The Onsrud catalogue (AKA the feed-rate bible) recommends a feed of 5-15 m/min at 12k-16k rpm respectively on a 2-flute, 2" wide surface planing bit; a 6-flute will triple that. Note that that bit is in the "Solid surface" section of the catalogue, so it's been made for acrylic benchtop material, rather than timber.

You can use that bit if you really want to, but it won't be long before it's blunt and burning your work.

Try to find a 2-flute planing bit, or even just a wide 2-flute straight bit.

[qwertyu]

Thanks. I had no idea.

Ill look through the catalog. I actually have some 2 flute bits which may be suitable, they arent huge though will have to check

[ian]

I think for router bits I will go with the carbitool surface planer
https://www.google.com.au/search?q=carbitool+tss+13+1%2F2&ie=utf-8&oe=utf-8&client=firefox-b-ab&gfe_rd=cr&dcr=0&ei=aFe7WpPFEqnM8gem6r7wCA

and the carbitool inverted flush
https://www.totaltools.com.au/42708-carbitool-tct-inverted-flush-trim-bit-1-2-dia-1-4-shank-t8216b

You guys think they will be suitable? is 2 cutter heads for the inverted flush enough (ie will it be a rough cut?)Elan has answered re the unsuitability of your suggested surface planer bit.

Your proposed flush trim bit is IMO also not suitable.
You need a proper rebate or dado bit -- flush trim bits are not designed to produce a flat bottom rebate, rebate and dado bits are.
If you can't find a suitable bit with a bottom bearing guide, you can use a guide bush template follower https://www.carbatec.com.au/routing-and-shaping/accessories-and-parts/brass-bush-set with a non-bearing bit
Tricky bit when using guide bushings is getting the off set between the guide collar and the cutter right.

[ian]

Meant to include comment on
In terms of glue - I looked at that thread - clear epoxy seems to be the suggestion. you guys think I should just glue the edge of the glass to the wood (glass might be 6mm think)? Or the entire surface which is sitting to the glass (more risk of air bubbles)get the glass before you cut the rebate.
Make sure you and the glass supplier understand what you are trying to do. The glass guy may even have suggestions of a suitable adhesive, or retainer

[Fumbler]

Have you considered making a frame around the 2 pieces to be side by side, and using dyed epoxy resin? could save you a lot of trouble.........

https://img1.etsystatic.com/201/0/13469424/il_340x270.1488934521_lm4x.jpg (https://www.google.com.au/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&ved=&url=https%3A%2F%2Fwww.etsy.com%2Flisting%2F585043811%2Fresin-river-dining-table&psig=AOvVaw1KNkdHogFCURhBwmdwbSsr&ust=1522338229891677)

This is my dining table, and you can see the epoxy is still very effective........nah, just kidding, its on my ta do list, as opposed to the ta dah list, you know the one you wave goodbye to cos no time to do it all.

[elanjacobs]

Your proposed flush trim bit is IMO also not suitable.
You need a proper rebate or dado bit -- flush trim bits are not designed to produce a flat bottom rebate, rebate and dado bits are.

False. ALL square-ended router bits will produce a flat bottom rebate equally well

[qwertyu]

Meant to include comment on get the glass before you cut the rebate.
Make sure you and the glass supplier understand what you are trying to do. The glass guy may even have suggestions of a suitable adhesive, or retainer

Yep good idea


Have you considered making a frame around the 2 pieces to be side by side, and using dyed epoxy resin? could save you a lot of trouble.........

https://img1.etsystatic.com/201/0/13469424/il_340x270.1488934521_lm4x.jpg (https://www.google.com.au/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&ved=&url=https%3A%2F%2Fwww.etsy.com%2Flisting%2F585043811%2Fresin-river-dining-table&psig=AOvVaw1KNkdHogFCURhBwmdwbSsr&ust=1522338229891677)

This is my dining table, and you can see the epoxy is still very effective........nah, just kidding, its on my ta do list, as opposed to the ta dah list, you know the one you wave goodbye to cos no time to do it all.

It might be a consideration for a future project but I really like the look of glass. Plus, as a beginner its a project where I can learn to use a router

Hows this one:
carbitool T1464 - $84.10 (seems so expensive!)

[elanjacobs]

That bit should work fine. Also not really expensive for a bit that size

[qwertyu]

There is also carbitool T1432 - 32mm diameter for $42

CMT equiv is this which seems cheaper.
https://www.carbatec.com.au/31-7d-x-5-7mm-mortise-bit-1-2-shaft

So I read mixed responses regarding CMT vs carbitool - what are people's thoughts

[elanjacobs]

Oops, hit like by accident

They are not equivalent. The CMT is 5mm long, the Carbitool is 38mm long, hence the price difference.

For surfacing, the CMT would be better simply because you don't need the length

[qwertyu]

Thanks - how about the general quality of the bits, staying sharp, clean cuts - is one brand better than other?

[elanjacobs]

I've never used CMT, but I know Carbitool are excellent and they're made in Melbourne so you get to support Aussie business

[GraemeCook]

Meant to include comment on get the glass before you cut the rebate.
Make sure you and the glass supplier understand what you are trying to do. The glass guy may even have suggestions of a suitable adhesive, or retainer

This is crucial.

Qwertyu, I suggest that you make a female template and then go and talk to your glazier. He will advise you on the types of glass and costs, the risks of breakage in cutting and will recommend quite gentle curves. These risks will be factored into his quote and you might be horrified. Then get the glass cut and edge polished.

Cut glass will always be a little different from the template. Then, either adjust the template or make a new one - probably the latter.

Then proceed as advised.

Whatever you do, do not cut the rebate until you have the glass cut. It will not fit.

This is one of those projects that looks simple but is actually quite advanced!


Cheers

Graeme

[qwertyu]

So I've emailed a bunch of glaziers in Melbourne and have only found 1 so far that can provide coloured glass, but not in teal. Does anyone happen to know any glaziers which may do it? I didnt think it would be so difficult to find someone

[elanjacobs]

I know Taranto Glass in Moorabbin has various colours and textures of stained glass for windows, they might be able to help

[qwertyu]

Thanks elanjacobs I gave them a call and he told me they dont do coloured glass anymore. But he gave me the supplier's details so will ask them who the retailers are

[qwertyu]

Just an update. Ended up going with 3mm acrylic, its just so much easier to get and also easier to cut. Finding someone to provide the glass prooved to be a hassle and I didnt want to spend any more time on it.

Also have some progress pics:

435594
The initial slab - southern mahogany. crack and the bit of soft/rotted sapwood filled/soaked with resin

435595
Cut the section I wanted for this project and the rest of the slab is stored for another day. Cleaned and filled gum veins and cut it down the middle. I too a photo of the slab first and put it into photoshop to plan how I wanted to cut it.

435596
Here it is flipped. I was pretty excited seeing this as it was a preview to how it would look

Next I planed and thicknessed it - dont have any pics. It ended up fitting through my machine so didnt have to use a router sled it was great.

435601

435602
Then I cross cutted it into thirds, the plan is to have 3x 350mmx350mm

435603

Used tracing paper to figure out how I want the river to be

435604

cut the acrylic.

Gotta make the negative template to route the groove next - which leads me to my next question.

I have an old makita trim router. The bit that holds the router bit is really tight - the thing inside the nut which squeezes the router bit - is it a collet? I basically have to undo the nut completely and then wedge it off the old bit. Also means that the bit I want to use is really hard to put in, basically have to use my body weight. Is this normal? Can I get a new inside thing somewhere?

[Alkahestic]

I have an old makita trim router. The bit that holds the router bit is really tight - the thing inside the nut which squeezes the router bit - is it a collet? I basically have to undo the nut completely and then wedge it off the old bit. Also means that the bit I want to use is really hard to put in, basically have to use my body weight. Is this normal? Can I get a new inside thing somewhere?

Not normal. The cylindrical piece that slips over the shank of the bits is the collet, it should only be really tight when the collet nut is tightened. You should be able to get a spare ordered in at any decent tool store, if the router isn't ancient. If you have your router manual or can find it online or try Makita customer service, it'll have the part number in an exploded diagram.

[A Duke]

Hi,
Maybe a quarter bit forced into a six mil collet.
Regards

[qwertyu]

Had a good look at the collet today and there was some rust so sanded it away and seems to be ok now :)

[aldav]

Hi,
Maybe a quarter bit forced into a six mil collet.
Regards

But most likely the nut done up tight without a bit in it. This permanently distorts the collet and replacement is the only option.

[qwertyu]

Routed the grooves today, the bit I was most nervous about. Its all down hill from here!

436060
436061436062436063

[woodcncmachine]

436360 This cnc router, how do you think？

[Mnb]

Looking good qwertyu.

[rod1949]

I appreciate this post is a bit old but I had the same issue when it came to a blue glass here in Perth as it was not available hence I settled for a blue acrylic.