Shapeoko 4: any 1/2” shank routers?

I have had my 4XL for 18 months and have built 10 guitars plus numerous other items. It’s a great machine. My biggest regret is not buying a machine with a 1/2” shank bit capacity. The machine itself is fine, it’s rigid, cuts accurate and meets my requirements as originally needed. Now, I would really would like to use a 1/2” shank bit to help with the cutting the 1.75” guitar body perimeter with less chatter.

Is there a 1/2” router that fits this machine? Don’t mind buying the larger mounting bracket to accommodate, but I know some larger routers can be too heavy.

Anyone done this mod?


Usually when folks move up to 1/2" tooling they get an HDZ:

and an 80mm mount:

and a spindle w/ an ER-20 collet.

That said, have you tried 8mm (5/16") tooling? It’s quite a bit more rigid than 1/4", and you can get either an ER-11 collet in that size (if you have the ER-11 Carbide Compact Router or VFD Spindle Kit) or a Makita collet which will fit the Standard Carbide Compact Router:

There is a 3/8" collet for the Makita Carbide Compact Router, but it has so little material to it most folks only use it for metrology.

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Thanks Will. I was not aware you could get an 8mm 5/16” ER 11 collet. That would be worth ordering the compact router with the updated collets.

To make sure you understand the 5/16 and 8MM are not the same thing. They are very close but use 5/16 for 5/16 bits and 8MM for 8MM bits. The two collets are not technically interchangeable. They are close but could lead to issues. I have used 5/16" bolts in place of an 8MM one but the bolts are not spinning at 18,000 RPM. So get both if you have both types of bits, or only the 8MM for 8MM bits.


For endmills in a clamping collet, in my experience, they are interchangeable, esp. for ER-style collets which have a quite wide clamping range.

That said, even for the smaller clamping range of the Makita-style collets:

8mm - 7.9375mm == 0.0625mm 

which is

0.00246063 inches

which is less than half a thousand more than the diameter tolerance for at least some endmill manufacturers.

I’ve successfully used my 8mm Elaire collet on a wide variety of tooling, both 8mm and 5/16". Even an undersize 5/16" endmill shouldn’t be much smaller than:


which is:

0.00446063 mm

well w/in the clamping range of an ER-style collet at that size — per:

all but the smallest ER-style collet sizes have a 1mm clamping range.

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Thanks all. For this particular usage, the bit would need to be 3” long. 1” into the collet and 2” below with a LOC of about 1.5 to 1.75”. This is to ensure it can cut all the way through the material, and still respect the Z travel. Because of that, the most important thing is to ensure the bit stays tight in the collet. I am current using the same spec 1/4” bit with good to very good results, but do get some chatter marks around the edge of the wood that requires some additional sanding to remove. I’m a bit nervous to run a final pass of say .010” at full depth with a 1/4” bit. I have done so on another machine with a 1/2” shank.

The material is usually Korina (white Limba) or Mahogany.

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Just to add context to what I am cutting, here is one body style. Material is 1.75” thick. Final cut is all the way through from one side. Neck and body are done separately.


I have the carbide er11 collet router on my so3 and use 8mm bits in it with no issue even on aluminum. I got the 8mm er collet from stepcraft


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