Muscle Chuck - The Faster Way To Change Router Bits

CNC Router Bit Changes Made Lightning Fast

Whether you have a CNC router or a hand-held router, you probably find changing your router bits to be a little inconvenient. You have to use 2 hands to manage 2 wrenches while trying to hold the router bit with your pinky. It seems to be one of those things we just have to deal with, but quietly wish there was an easier way to change router bits. 


I'm Garrett Fromme, an CNC expert and CEO of IDC Woodcraft, the CNC router bit company dedicated to providing you with high-quality router bits, and all the necessary information needed to use them correctly. 


This article discusses a revolutionary new device that makes router bit changes much easier and faster!

The old way of changing router bits

The Router Bit Changing Issue

If you own a CNC router, or even a hand-held router for your woodworking projects, you are likely aware that changing router bits using the standard 2-wrench method can be a bit of a hassle. Juggling two wrenches with two hands while trying to position the router bit properly in the collet is almost a 3-handed job. 


How many times have you had to loosen and retighten the collet because the bit was not in the collet far enough? Positioning the router bit correctly requires a bit of dexterity because your hands are busy working 2 wrenches.


At least with hand-held routers, you can position it bottom-up to change the bit. On CNC routers, you have to bend over to see what you are doing, somewhat skewing how you set the router bit position. It also takes a minute or 2 to complete the router bit change using the traditional 2-wrench method, regardless of whether you have a hand-held router or a CNC router. 


The worst is when you are loosening the collet and the bit drops out, bounces off the table and lands on the floor, chipping the cutting edges. 

But, finally, there is a solution!

In Comes The Muscle Chuck

The MuscleChuck is a revolutionary router bit holding device that is quickly replacing the old nut and collet method of holding CNC bits


The MuscleChuck completely eliminates the traditional nut/collet, 2-wrench method of installing a CNC router bit into your CNC router. It allows you to loosen and tighten your router bit with only ONE WRENCH (7/64 hex wrench) while you are holding the router bit with the other.


It is available for most ER-style spindles and CNC routers that have trim routers (like Bosch, DeWalt, Makita, Festool, Porter-Cable, Ridgid, etc.).

The MuscleChuck for the Makita trim router RT0701C

As stated earlier, there are a couple drawbacks to the traditional nut-collet method of holding CNC router bits. They are:

  • Risk of Bit Damage: The two-wrench method increases the risk of dropping your router bit onto your workpiece or the floor, leading to possible chipped cutting edges.
  • Time-Consuming: Changing router bits using two wrenches can be time-consuming. In a busy workshop, those minutes add up quickly and could be better spent on actual woodworking projects.
  • A Necessary Inconvenience:  The nut-collet method has been just how it’s done but, at the end of the day, it is generally inconvenient for the user.

How The MuscleChuck Works

The MuscleChuck is machined to seat in the spindle taper just as a standard collet would. This aligns the bore of the MuscleChuck to run true in the spindle or router.. The attached nut pulls the unit into the taper, forcing it to seat tightly and align itself.


From here, a 1/4" shank rouer bit can be inserted in the bore. A single hex wrench is used to clamp the split end of the unit to the router bit.

See the image to see the taper that seats and aligns the MuscleChuck

Testing The MuscleChuck

I tested the version of the MuscleChuck designed for the Makita trim router model RT0701C using the Longmill MK2 CNC router, which typically comes with this particular trim router. To see a deep dive review of the Longmill CNC router, watch this video.


In general, this model of the Makita trim router is appropriate to test the MuscleChuck on because it is a common choice for benchtop CNC router manufacturers. However, Musclechuck is are available for many other routers and spindle brands as well.


The testing was to confirm the following performance:

  • Runout
  • Slippage
  • Deflection
  • General performance

One of the concerns I had with the MuscleChuck was the nut loosening up over time and unseating the unit, which would result in a messy cut due to wobbling of the bit. As I tightened it on the router shaft, I could feel it seating. Once seated and tight, I gave the MuscleChuck and extra snug. Throughout the testing and running a few other projects, the concern went away because it stayed tight on the router.


This was an easy check using a standard dial indicator. Dial indicators are good tools to have to get accurate measurements for aspects of your CNC, like checking for runout.


The maker claims a maximum runout of 0.001" whick is a very tigh tolerance.


I measured 0.0015” which is slightly over the maker claims, but I have to be real... a 0.0005" is almost nothing and is way within acceptable limits and exceptional for CNC woodworking. The runout I measured may be attributed to variations in my router (which has had quite a lot of use at the time of this test). 


This level of precision is quite impressive, and more than is needed for CNC woodworking projects.

MuscleChuck has a very small 0.0015" runout

Slippage & Deflection

Router bit slippage is not a good thing to happen to your projects. Slippage is when the router bit slowly slides up or down the collet during the carving process. In te standard nut/collet setup, the biggest cause of slippage is from sawdust that is between the collet and the bit shank (and is why the collet must always be cleaned during every bit change).


I wanted to make sure the bit would not move during a carve, which would ruin a CNC project. This required some deep pocket cuts at higher than normal feed rates that would put undue forces on the bit. There was no slippage.


I tested this part with 3/16" compression bit from IDC Woodcraft. Compression bits in general tend to make a bit more noise when carving, and there was a detectable increase in sound coming from the router bit while using the MuscleChuck. This may be due to the fact that the MuscleChuck does require 1/2” more extension at the end of the router to afford the clamping system it uses. However, there was no sign of reduced cut quality or extra bit deflection. 

Clearing Sawdust From The MuscleChuck

All collets require cleaning after every bit change to remove any sawdust that got inside. 


Sawdust squeezed between the collet and the bit shank can act like a 'lubricant' which can allow the router bit to slowly slip during a carve. This is part of why changing a bit takes a couple minutes with the nut/collet method. The collet must be completely removed, blown out to remove any sawdust inside, and reinstalled.


The MuscleChuck has one small slit for clamping the bit so it is much harder for sawdust to get inside it. However, to clean it, I simply used a Q-Tip which was quite easy. I just had to rob my bathroom cabinet. 


Cleaning sawdust from the clamping surface of the MuscleChuck was actually faster because I did not have to remove the collet. 

Cleaning sawdust from the MuscleChuck

See The MuscleChuck In action

In this video, you will see how quick a router bit change is with the MuscleChuck adaptor vs using the 2-wrench method.


This example was done on the Longmill MK2 CNC router. If you are currently considering a CNC router but are not sure what to look for, please watch this video titled, "The Ultimate CNC Router Buyers Guide".

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Pros & Cons

As with any tool, there are both pros and cons. I summarize them here.



  • Extremely fast bit change - about 5 seconds (vs 1-2 minutes for nut/collet).
  • Easy 2-handed operation.
  • Requires 1 wrench.
  • The micro-slit limits the amount of sawdust that can get in the assembly.
  • Does not require removal of a collet and nut for cleaning.



  • Requires a 1/4-1/8 collet reducer for 1/8" shank router bits (adaptors are used quite commonly since this is a normal issue with nut/collet setups)
  • When it wears, a whole new MuscleChuck will be required. 
  • Will need to have Q-Tips, or some other probing item to clean the collet of sawdust.
  • Takes up an extra 1/2" of Z clearance

Summary Of Performance

After using the it on other projects, the performance of the MuscleChuck passed with flying colors. The bits did not move and change-over time was lightning-fast. 


Although we loose a little Z clearance, this is easy to compensate for by simply repositioning the router up a little in the mount.


In the CON statement above about a full replacement when the MuscleChuck wears out, this is something of a moot point, in that although all collets eventually wear out, the time it takes to do this is substatial, and dependant on heavy daily use.


In conclusion, if you own a CNC router in your home or workshop, the Musclechuck proves to be a game-changer when it comes to bit changing. It's a revolutionary solution that will make your router bit changes fast and easy. If you decide to upgrade to the Musclechuck, you can now get it from IDC Woodcraft. 


Happy woodworking!

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