Flush router bit for 60mm hardwood join.

[Jitter]

Happy Holidays everyone. Looking for a little advice from the grapevine.

I have taken on a project for a client with a set of burr elm book-matched slabs to be joined. Although the wood is well prepped and dry/flat, the long square edges to be joined need straightened with only a few mm out from one end to the other.

Although I have the Wadkin planer which always does a good job in creating flat and square edges, these slabs are quite hefty and wide so accuracy I guess in this regard may be difficult.

The slabs are approximately 60mm in thickness and I think that running a router freehand off a factory straight edge of ply or similar would do for flush routing.

My question is, what half inch flush router bit would you suggest for the job if they are available in the length required? Presumably a straight vertical cutter would be best to prevent breakout on the surfaces?

Sometimes asking what has been tried and tested by others can prevent problems, I like to learn the easy way. Any guidance is much appreciated.

 

[RobinBHM]

I’d be tempted to try this:

https://www.wealdentool.com/acatalog/Online_Catalogue_Multi_Trim_270.html
Im not a 100% sure but I think if you removed the bottom bearing, did a say 45mm trim on one side, put the bearing back and flushed the other side it would work.

these cutters are far better than the usual trim cutters - they are 19mm dia and being disposable blades are proper sharp - I’ve used them to trim a full cut on 12mm birch ply no problem and will take off 6mm from 18mm birch easily. When brand new cutters are on, they will trim against the grain cleanly too, if done with finesse.

 

[TRITON]

Down cut spiral bit ?.
Taking care as the spiral can lift the router so keep fair downward pressure on it during use.
Im not sure you would be able to do it in a single pass. I think its only max is about 50mm
Failing that a xl long straight bit the type of which is for kitchen fitting in cutting worktops. Some come with a slightly angled cutter for a shear action, which should keep the top surface chip free.

 

[Jitter]

I’d be tempted to try this:

https://www.wealdentool.com/acatalog/Online_Catalogue_Multi_Trim_270.html
Im not a 100% sure but I think if you removed the bottom bearing, did a say 45mm trim on one side, put the bearing back and flushed the other side it would work.

these cutters are far better than the usual trim cutters - they are 19mm dia and being disposable blades are proper sharp - I’ve used them to trim a full cut on 12mm birch ply no problem and will take off 6mm from 18mm birch easily. When brand new cutters are on, they will trim against the grain cleanly too, if done with finesse.

Thanks. I’ve used Wealden cutters for slab flattening before, I’ve found their bits to give a good quality finish.

 

[Jitter]

I’d be tempted to try this:

https://www.wealdentool.com/acatalog/Online_Catalogue_Multi_Trim_270.html
Im not a 100% sure but I think if you removed the bottom bearing, did a say 45mm trim on one side, put the bearing back and flushed the other side it would work.

these cutters are far better than the usual trim cutters - they are 19mm dia and being disposable blades are proper sharp - I’ve used them to trim a full cut on 12mm birch ply no problem and will take off 6mm from 18mm birch easily. When brand new cutters are on, they will trim against the grain cleanly too, if done with finesse.

Thanks. I guess I could use a guide rail against the flat edge of the router base for a straight edge

Down cut spiral bit ?.
Taking care as the spiral can lift the router so keep fair downward pressure on it during use.
Im not sure you would be able to do it in a single pass. I think its only max is about 50mm
Failing that a xl long straight bit the type of which is for kitchen fitting in cutting worktops. Some come with a slightly angled cutter for a shear action, which should keep the top surface chip free.

Thanks.
Actually a long kitchen cutter may be the answer if I just run the base of the router along my plunge saw guiderail or another straight edge. I have seen 70mm kitchen cutters.

 

[Jameshow]

Clamp both pieces together and run edge through the pt together end on!

that way the edges are matched?

Going to need a helping hand?

 

[TRITON]

Actually a long kitchen cutter may be the answer if I just run the base of the router along my plunge saw guiderail or another straight edge. I have seen 70mm kitchen cutters.

This one is 63mm cut. Overall length 115mm
Priced at a very keen £31.80
https://trenddirectuk.com/trend-tr3...MI_dTer7b19gIV4-jtCh2UpQpNEAQYBCABEgLy3_D_BwE
However, the 70mm depth of cut, which at 60mm thickness of board you dont need, is £51.48
https://www.trend-uk.com/c023dx1-2t...t-router-cutter-bit-14mm-dia-x-70mm-cut-depth

 

[Jitter]

This one is 63mm cut. Overall length 115mm
Priced at a very keen £31.80
https://trenddirectuk.com/trend-tr3...MI_dTer7b19gIV4-jtCh2UpQpNEAQYBCABEgLy3_D_BwE
However, the 70mm depth of cut, which at 60mm thickness of board you dont need, is £51.48
https://www.trend-uk.com/c023dx1-2t...t-router-cutter-bit-14mm-dia-x-70mm-cut-depth

Thanks Triton, I’ll take a look at these.

 

[Jitter]

Clamp both pieces together and run edge through the pt together end on!

that way the edges are matched?

Going to need a helping hand?

Thanks for the idea. I have heard of people doing it this way although was unsure about myself making a good job of doing both slabs at the same time.

I guess if I lifted both slabs from the flat surface using the same thickness packers I.e. plywood or mdf strips, I can set the gap to enable as much clearance as possible but still engaging fully on each edge with the blade from end to end. Proceed to do it in one single pass with the boards clamped down using a long twin fluted kitchen cutter?

 

[Jitter]

Clamp both pieces together and run edge through the pt together end on!

that way the edges are matched?

Going to need a helping hand?

I see now! Run the two boards clamped together through the planer! Now there’s an idea I would never have thought of that.

 

[Distinterior]

With 2 pieces of wood that size, weight & thickness, I would be inclined to square the edges up using a router and doing it by way of a " Mirror Cut".

If the 2 edges have a mm or so gap when pushed together, then just clamp the 2 pieces down flat on a good flat surface. If your router cutter is 19mm diameter, then space the 2 pieces apart by about 16/17mm and set up your router and a good straight edge that will allow you to run the cutter right down the middle of the gap.
The cutter will remove 1mm or so from EACH edge of the 2 boards at the same time.......Even if your straight edge isn't perfectly straight, the cutter will mirror the cut on each board.
When you push the 2 boards together, they should marry up perfectly, even if the joint is not perfectly straight.....

I've cut many a butt joint like this on various materials and its always worked very well.

A couple of tips I can give you are,....Don't try to remove too much material in one pass!
Get the 2 edges as straight as possible before you do the mirror cut.
One uninterrupted cut removing minimal material always yields the best results.

 

[Jameshow]

With 2 pieces of wood that size, weight & thickness, I would be inclined to square the edges up using a router and doing it by way of a " Mirror Cut".

If the 2 edges have a mm or so gap when pushed together, then just clamp the 2 pieces down flat on a good flat surface. If your router cutter is 19mm diameter, then space the 2 pieces apart by about 16/17mm and set up your router and a good straight edge that will allow you to run the cutter right down the middle of the gap.
The cutter will remove 1mm or so from EACH edge of the 2 boards at the same time.......Even if your straight edge isn't perfectly straight, the cutter will mirror the cut on each board.
When you push the 2 boards together, they should marry up perfectly, even if the joint is not perfectly straight.....

I've cut many a butt joint like this on various materials and its always worked very well.

A couple of tips I can give you are,....Don't try to remove too much material in one pass!
Get the 2 edges as straight as possible before you do the mirror cut.
One uninterrupted cut removing minimal material always yields the best results.

Double

 

[baldkev]

The photos below show a desk top i made as described by Disinterior above.

You can set the router depth to say 5mm and buzz through, set depth to 10mm and go again etc. For this it'd be wise to set up a second board as a guide to create a channel to run the router down so it cant slop about.
Im my case i had a curved template which i ran against for one cut, then finished the rest off with a flush trim bit.... this was brcause i didnt want to risk messing up/ not being dead tight to the template for 5 or 6 depth passes....
I would very much recommend a good quality top bearing flush trim bit, not a cheap chinese one. In fact, that goes for any router bit to be honest!

 

[Jitter]

Thanks guys, a few different ways I could tackle it then. In an attempt to save on setup and cash, I’ll try clamping the boards and planing them first. I’d be hopeful about doing it that way and the planer does give good results, it will be good to know for future too. It only needs a minimal amount off each board and they are flat already. If for any reason it proves to be difficult, I’ll give the mirror cut a go as I can see that working well also. This would probably be a good way to do it if I knew the boards were simply too long to get a decent result on the planer. The only thing that was putting me off using the planer was that they would not be cut at the exact same angle but cutting them together of course should eliminate that problem. I will fold them up like butterfly wings and clamp them, get a hand from a trusty friend to lift them and try that first. I’ll let you all know how it goes.

Thanks for all the help

 

[RobinBHM]

I’ve found these Erbauer bits fantastic quality - better than or as good as trend

1/2” x 63mm £11.99

https://www.screwfix.com/p/erbauer-...cDh_IfhZN1fVXLBh_QkaAvRjEALw_wcB&gclsrc=aw.ds

 

[baldkev]

If its close enough, can you hand plane? It might be just as quick by the time youve tried other things. With clamping and planing on a p/t, the outfeed face needs to be dead flat all the way through, otherwise any discrepancy will be doubled when you put the 2 edges together.

 

[pgrbff]

I've just bought a cmt up/down CMT spiral TCT cutter at a great price. This should ensure minimal breakout top and bottom.
https://www.scosarg.com/search-results#/embedded/query=CM19012011&query_name=match_and
It was less than half the discounted price here in Italy.

 

[Distinterior]

I've just bought a cmt up/down CMT spiral TCT cutter at a great price. This should ensure minimal breakout top and bottom.
https://www.scosarg.com/search-results#/embedded/query=CM19012011&query_name=match_and
It was less than half the discounted price here in Italy.

Nearly £53 Inc vat,....not exactly cheap and it needs a 12mm collet....not every router has the facility to fit a 12mm collet, hence why its probably been reduced in price...??

 

[pgrbff]

I wouldn't call it expensive either for a solid TCT bit, not if you're going to use it to make a living. I looked at the Wealden compression bits and I think they were more or less similar price.
I have 12mm because most large bits here are 12 not 1/2".
I have always tried to stick with Titman but Brexit has put a stop to that.

 

[hlvd]

A track saw would give you a straight edge and depending on the blade would possibly give an edge with minimal cleanup.

Another way is to run a groove with a router up to it maximum depth, cut off what’s left leaving a slight protrusion and then flush cut from the opposite side.

Failing all that, cut away from the line with whatever saw you’ve got and clean up with a No7/8 or whatever 2 3/8” plane you’ve got at your disposal.