Surface planing router bits

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Forum topic by IdeasYouSpark posted 05-09-2020 08:21 PM 430 views 0 times favorited 15 replies Add to Favorites Watch
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16 posts in 85 days

05-09-2020 08:21 PM

Topic tags/keywords: resource tip question cherry maple walnut zebrawood purpleheart cedar padauk router planer milling shaping finishing sanding rustic arts and crafts traditional

I have a Makita trim router with a 1/4” shank and wanted to dip my feet into surface planing a slab. Now I realize that a full size router with a 1/2” shank would be much more efficient, but I’m trying to work with what I have available at the moment. Would anyone have some advice as to what router bit to use for surface planing with a1/4” shank? I see a lot of opportunities for a CNC, but I’m unsure of the compatibility. Thank you!

-- IdeasYouSpark

15 replies so far

View Madmark2's profile


1371 posts in 1360 days

#1 posted 05-09-2020 09:21 PM

For small areas a 1/4” might work – for a while. The 1/2” dissipates 4x the heat of the 1/4” and will last corresponding longer. HSS bits are a waste of $$$, esp. in this app.

The larger size allows larger cutters for fewer passes, less time, less uneven overlap, less sanding.

-- The hump with the stump and the pump!

View LittleBlackDuck's profile


4686 posts in 1593 days

#2 posted 05-09-2020 10:26 PM

CNC’s usually use small bits and for surface planing they would take consistent shallow depths when using a larger bit while working from a level downward horizontal plane… which would be impossible manually (at least without a jig)...
Trying with a trimmer would be a sure way of forcing you to buy a replacement router/trimmer when it burns out.

The alternatives are endless… 1/2 router, belt sander, jointer… The trimmer may be a futile exercise, like sailing from England to the USA (flights permitted post C19) in a paper boat.

-- If your first cut is too short... Take the second cut from the longer end... LBD

View dbw's profile


414 posts in 2409 days

#3 posted 05-09-2020 10:35 PM

I think your trim router will burn up PDQ with this kind of use.

-- measure 3 times, cut once

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1371 posts in 1360 days

#4 posted 05-09-2020 10:53 PM

I’d suggest an 1/8” straight cutter …

-- The hump with the stump and the pump!

View therealSteveN's profile (online now)


5760 posts in 1346 days

#5 posted 05-10-2020 08:11 AM

With a “surface planing” bit you are trying to flatten while keeping the most usable stock available. With them a broad face mounted on a 1/2” shank gets it done. CNC you are using a tiny point in constant motion to dig out a pattern, For the types of tiny pointy bits, most are small shanked 1/8” or 1/4”.

You are asking the tool that handles only the tiny shanks to do the work of a large shank bit.

I see frustration, and many broken shanks. Perhaps a low $$$$ 1/2” shank capable router? Even a 1 3/4 HP router with a 3/4” diameter planing head will be able to do the work, slowly yes, but capable.

Best of luck.

-- Think safe, be safe

View Berto's profile


20 posts in 2263 days

#6 posted 05-10-2020 11:51 AM

This bit will fit a trim router and your needs to dabble in surface planing a slab.

It’s a 1/4” shank, 1” wide and will cut 1/4” deep if needed. Although with a trim router wouldn’t try to max the depth out. (It also comes with a 1/4” to 1/2” bushing also – as pictured).

-- - Berto in VA -

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John Smith

2429 posts in 935 days

#7 posted 05-10-2020 12:11 PM


when you get started in your project, please come back with some photos
of the system you decided to go with. inquiring minds want to know.
(you didn’t mention what size slab you are working with).

this is my Mini-Slab that would have been a good candidate for a trim router.
most of us here are pretty much geared to the “size” of a “slab” being the
size of a table of some kind. I made this “mini-slab” for my aunt as a condiment
holder for a banquet table. so the word “slab” has different meanings to different folks.
(it is Olive Wood about 20” x 8”).


-- there is no educational alternative to having a front row seat in the School of Hard Knocks. --

View IdeasYouSpark's profile


16 posts in 85 days

#8 posted 05-10-2020 03:27 PM

Thank you for your words of wisdom, everyone! I kinda figured investing in a 1/2” rounter would be a better idea – especially after just getting my new trim router for Christmas last year. I’m rather fond of it and would rather not kill it.

As for the size of slab and project…

I don’t have a particular project in mind… yet! I thought it would be a good idea to start practicing on a small size slab first before diving headfirst into a premium slab I go salivating over. Those slabs aren’t cheap, and neither are replacing routers.

-- IdeasYouSpark

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5760 posts in 1346 days

#9 posted 05-10-2020 06:37 PM

I grew up in the time when a 1/2” shanked router bit was a LONGgggggg wait for it mail ordered, so most of us older guys used a LOT of 1/4” bits.

I can reasonably assure you if you did use the 1/4” shanks to plane with, on any random rough wood surface that one of 2 things would happen, and I doubt your new mini friend would be injured.

1) you would really watch where you were headed, and take the lightest of very shallow passes. The problem with rough wood is a lot of time you would only be planing air, then you would be trying to plane 1/4” of wood. Keeping it so you always only took a shallow pass would bore me to sleep, not sure about you?

2) You would say, a the heck with it, I got things to do. In which case the 1/4” shanks snap off like twigs.

Again, I don’t think your router would burn up as suggested, the shanks would break off first. Now if you want to use the mini for doing dados, edges, or whatever, sure go ahead. Easily controllable, and by not forcing the bit you can go a long time on a board that is already flat. Rough wood isn’t flat.

Sadly you just missed Rockler selling Porter Cable 690’s for 99 bux. They are 109 now I think.

Best of luck.

-- Think safe, be safe

View AndyJ1s's profile


325 posts in 527 days

#10 posted 05-10-2020 07:10 PM

A trim router is really not the tool for this, but if you are very patient, it can do well enough on a small job.

Just because a 1” cutting diameter bit has a shaft that will fit in a trim router, doesn’t mean it is suitable for an under-powered trim router.

I would not use anything bigger than 1/2 inch cutting diameter for a full-diameter cutting bit (i.e. not a piloted, edge trimming bit) in a trim router. And go slow with lots of very light passes.

Make sure the bit is not a down shear cutter (often used for hinge mortising bits, to reduce tear-out at the edge of the mortise, which is not important for this task.) You definitely want up shear or straight cut (no shear, cutter surface is right angle to end-plane of bit) for this application.

-- Andy - Arlington TX

View CaptainKlutz's profile (online now)


3171 posts in 2266 days

#11 posted 05-10-2020 10:48 PM

+1 Use 1/2” shaft router and bit! Much faster, and less frustration on larger panels.

Question: Do you have the actual trim router (4A or 1/4 HP), or larger 1-1/4HP ‘trim’ router?
Would not even attempt to surface plane with small trim router, but the larger 1-1/4 could be used.

Have used a small DW611 router with 1/4 shaft bowl & tray bit for surface planing a small slab project?

IMHO – The radius bowl & tray bits work better than other options I have tried?
The radius edges don’t leave witness lines when planing sled is not rigid, and the radius helps to provide increasing feedback when you attempt to cut too deep.

Highly suggest you go slow, keep cut depth to 1/8 in or less AND cut width per pass to < 1/2 the bit width, or you might bend the shaft. DAMHIK!!
For shallow 1/32-3/64 final cut, you can use the entire bit width with success.

The biggest issue with small router is size of base .vs. router height. It is really easy to tip a couple degrees and not plane surface flat. Have same issue with larger router, but the small base exaggerates the issue. The radius edge bit helps reduce the gouges at corner, but does not fix non-rigid sled.


-- If it wasn't for bad luck, I wouldn't have no luck at all, - Albert King - Born Under a Bad Sign released 1967

View IdeasYouSpark's profile


16 posts in 85 days

#12 posted 05-11-2020 01:43 AM

CaptainKlutz My Makita Trim Router is the 1 1/4 Hp with both fixed and plunge bases. Se runs smooth and like a striped ass ape going through maple and pine like butter. Haven’t tried it on anything harder yet. Having the patience to go slow and shallow is not an issue. I’m retired and woodworking is my zen. Thank you for the insight. Good info to know!

-- IdeasYouSpark

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16 posts in 85 days

#13 posted 05-11-2020 01:50 AM

I don’t have too many bits yet, but none are downward. Give me time!

-- IdeasYouSpark

View LittleShaver's profile


674 posts in 1392 days

#14 posted 05-11-2020 07:06 PM

I do my slabs with hand planes. Most of the noise comes from me and the mess is a pile of shavings. I don’t do many slabs so the time invested in making a sled and firing up the screaming dust maker just isn’t worth it to me.

-- Sawdust Maker

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4098 posts in 3881 days

#15 posted 05-11-2020 10:33 PM

I needed to clean up the small slippage from gluing up walnut planks while making my last tool chest for my carving tools. I cheated and used a CNC spoilboard bit in my router. I have a sled I made from a 2’ X 4’ slab of MDF with aluminum angle runners. The bit was 1/4” shank and 1” diameter. I didn’t see a need to go to a bigger one, given that I didn’t have that much surface area to cut. It was done with my PC 690 router.

-- Steven.......Random Orbital Nailer

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