# Musclechuck



## N'awlins77 (Feb 25, 2011)

Alright, got my "correct" Musclechuck in today. It's going to be a while before I actually get to use it, so I wanted to check it out, as I read either here, or another review somewhere's that someone's Musclechuck had some bad run-out, and had to be returned. So I didn't want to find this out, later on down the road, that I had a bad Musclechuck. 

So first pic is checking the spindle of my Ridgid router (no collet). And with this indicator that only reads in thousands, I could barely see the needle move, not even registering a .0005 (half thou) movement. 

Next is with my original Ridgid collet assembly. With the new center finder I just purchased from EagleAmerica. So it could be the collet, or it could be in the brass center finder. But I picked up .0015 (thou/half). 

Next I installed my new Musclechuck and the same center pin, with the same amount sticking out. First try I got .010 (10 thou). After adjusting the chuck (either time, no noticeable vibrations) as per the instructions for vibrations, the best I can get is .005 (5 thou). 

Question is, is .005 run out something to be worried about on a router. I'm a machine shop mechanic, so I work in tenths of thousands when setting up a machine, sometimes. So I may be over thinking this. What do the masses say. 5 thou ok?


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## old55 (Aug 11, 2013)

Can't help you with that Lee but I'm sure someone will be along to give advice.


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## DaninVan (Jan 1, 2012)

Lee; good stuff. It's great when other members that have the skills and knowledge apply it to what the rest of us just make assumptions about.
Whatever the final answer, again, thanks for taking the trouble.


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## billyjim (Feb 11, 2012)

Lee I can't give you an answer based on any data but I do recall reading one time when a similar question was raised that the movement in wood occurring on a daily basis was greater than the "error" rate you have measured and that you will never get it dead on since you will always have the problem of wood movement to contend with. If you had a massive runout that would be another story but this seems like very acceptable tolerances to me.


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## tvman44 (Jun 25, 2013)

No way to measure mine, just know it works we'll and I love it.


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## paduke (Mar 28, 2010)

Lee
I found this post
http://www.routerforums.com/general-routing/1845-router-runout.html 

Logic tell s me that if a base wobbles a little the top wobbles more Not sure whats acceptable Perhaps we need a thread on runout in general


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## harrysin (Jan 15, 2007)

Your photographs don't show how the dial gauge is mounted and how was the router turned?


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## DaninVan (Jan 1, 2012)

Harry; ?...
The only variable between the three setups was the MuscleChuck. Any other factor should have shown up on the _other two_ setups.


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## N'awlins77 (Feb 25, 2011)

harrysin said:


> Your photographs don't show how the dial gauge is mounted and how was the router turned?



Harry, the gauge is mounted on a piece of wood, that is in turn clamped to my table. I just slid it over a little, to change each set up. And I turned the spindle by hand. All done the same.


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## N'awlins77 (Feb 25, 2011)

You are welcomed Dan. I think what "hurts" me is I work with close tolerances all day on my job, with metal cutting machines, and so I tend to get a little carried away when I get home to my hobby!! ;o) And like I said, I don't think I'm going to get to really try it for some time, and I had read how someone's had been out bad, so i just wanted to make sure mines wasn't. I don't think 5 thou is bad, when it comes to wood working. Like one poster said on that link that Bill found. Wood moves, on it's own, a heck of a lot more then 5 thousands. And I know it's only 5 thousand more, but I think I'd have been more concerned if I couldn't get it less then 10. But after just loosening the nut and turning it a little, it went from 10 to 5. I also took it all apart and made sure it was clean. As with in my field, a little speck of dirt can through you way off.


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## DaninVan (Jan 1, 2012)

Lee; what you said, but...
You're not dealing with "wood"; the Muscle Chuck is part of a _machine_ and needs to have the same tolerances as any other precision machine. 
That chuck could just as easily end up on a CNC setup for machining precision metal components, or circuit boards. .005" would be unacceptable in those situations.
The fact that you want it for processing _wood_ isn't relevant.
From all the good things that have been said about the MuscleChuck folks, I think they'd want to know about this problem. As I said, they could unknowingly be sending product out to very demanding clients for whom this _is_ a big deal!


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## neville9999 (Jul 22, 2010)

Lee lets say that you did set it up with a 'zero tolerance' and the you ran you cut with 'zero error movement' so you get a then technically perfect cut, then you sand it with fine sandpaper, how many thou do you think you will sand off by doing that? And do you think that sanding the cut will ruin the work? Don't worry about 'thou' Lee, The Muscle Chuck is a good one and I'm thinking about buying one, if the router does not have a busted bearing then put the cutter in and run your cut, think about doing a good pass, have a good plan, Oh and use sharp quality cutters, keep your work area clean, use Hearing and Eye protection, work safe. N


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## Cherryville Chuck (Sep 28, 2010)

I don't own one yet but I think the 2 things that would concern me is if cut quality degraded and mostly if it vibrates and it didn't before you put it on.


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## N'awlins77 (Feb 25, 2011)

Dan, I did write John, over at Musclechuck, about my findings. Haven't heard anything back from him yet. And I exactly hear what you are saying, and is how I felt, just didn't know if I was over analyzing it or not. I don't have a problem with 5 out. 10, I was kind of iffy! ;o)


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## Nickp (Dec 4, 2012)

Lee...you probably have the right tools to measure IDs and ODs...

May I suggest measuring the OD of the center pin vs the ID of the Musclechuck... It's possible that the additional runout could be the difference between the ID of the Ridgid vs the ID of the Musclechuck and the OD of the center pin. The center pin may be a better match with the concentric Ridgid chuck vs the side squeeze of the Musclechuck.

I would then do the same measurements with a real 1/2" bit...

For example, if the center pin is .490 and the Musclechuck expects .500 you would get runout (mathematically) of .005 due to the Musclechuck squeezing only on one side... Example only

There might not be a problem... Just thinking out loud...

Nick


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## N'awlins77 (Feb 25, 2011)

Nick, not a bad thought. BUT, the brass centering pin actually fit tighter in the Musclechuck as any 1/2" shank router bit I have. I had to finely sand the pin, to even get in the Musclechuck. When I couldn't get it in, I thought, "oh oh, Musclechuck may not open up enough". I then tried a couple of my 1/2" bits, and they fit right in. So in fact, using a digital caliper, I measured the brass pin, it measured like .499.5, where as, most of my bits, new and old, measured no closer then .498. So I chucked the brass center finder in my drill press and with 220 grit emery, polished the pin down to .498.5. If still fit a little tighter then the bits, but at least I could get it in. After sanding the brass pin, I tried again in the original collet, and it still only showed about 1.5 thou run out and 5 on the Musclechuck. But that was a good thought!!


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## Nickp (Dec 4, 2012)

Lee...looks like you're gonna have to move the hole 2 1/2 thou... 

I personally haven't gone the Musclechuck route for no other reason than a whole instruction sheet on how to deal with vibration and runout. No disrespect to Musclechuck owners or anybody considering it...just my own mental block as I'm sure it is not an issue. My early years building performance engines scarred me, I guess...I'm certainly not that critical with wood...

Good luck with it...truly hope mfg takes care of it for you...Nick


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## N'awlins77 (Feb 25, 2011)

LOL Nick!! But John e-mailed me back last night, and told me he can get me much closer. He says his Ridgid router had about the same run out (.0015) with the factory collet, and he got the Musclechuck to O. He said it is a process, and too long to e-mail. So he said if I would give him my phone number, he will call me at a time convenient to me, and we'll get it much closer.


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## Nickp (Dec 4, 2012)

N'awlins77 said:


> LOL Nick!! But John e-mailed me back last night, and told me he can get me much closer. He says his Ridgid router had about the same run out (.0015) with the factory collet, and he got the Musclechuck to O. He said it is a process, and too long to e-mail. So he said if I would give him my phone number, he will call me at a time convenient to me, and we'll get it much closer.


Thanks, Lee...I'd be interested in your experience getting it zero'd...

The MC specs in the instruction sheet indicated a MC ID of .5002 to .5007...wonder why your .499 didn't fit...I did appreciate the technical description of how the finger clamps around the bit...it explains the reason to not over tighten...

I haven't ruled out buying the MC...just not high on my "needs" list...too many other "wants" to get through. 

Hope all goes well...Nick


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## Semipro (Mar 22, 2013)

Have been reading this post with interest, then the funny thought creeped into my head over the years I have accumulated seven routers 2 with musclechucks, walked into the store or bought them online and never once have I checked the runout on any of them.
Guess I have been lucky!


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## harrysin (Jan 15, 2007)

I've spent a lot of time on Google this afternoon and my conclusion is that VERY FEW woodworkers test their routers for run-out. It appears that like me, if there is no vibration and the cut is clean, there is no reason to check. I came across this MUSCLECHUCK information. I also saw the original patent application, not for the MUSCLECHUCK but for it's predecessor which was called the DeRosa chuck, which was sold and is now known as the Eliminator.

Run Out Sources & Corrections	
Click Here To Download A .pdf 
Of The Run Out Sources & Corrections
The Musclechuck has several advantages over other quick-change chucks that will become apparent once this article is reviewed. However, first I would like to discuss run out and the proper mounting of the Musclechuck. 

Mounting the Musclechuck might seem a little tedious at first but if the procedure is followed it will minimize run out. There are many contributing factors that cause run out such as, imperfectly ground spindle, worn bearings, high and low spots in plating, chuck bore size, chuck clamping technique, and finally, quality of machined parts. Mounting a solid chuck instead of a collet is slightly more critical because the chuck doesn’t conform as well to the defects that might be present in the spindle. Older spindles or ones that have been used a lot don’t usually suffer from this problem as much as new ones because over time the spindle will wear down and thus become more concentric. Just perform this simple test, remove and replace your standard collet and indicate the run out with a dial indicator, you might be surprised with the results. In order to minimize run out, mount the Musclechuck in the router spindle tighten the nut to no more than 12 ft-lbs. If you don’t have a torque wrench, Finger tighten the nut until its snug. Then use a wrench to tighten it no more than a quarter of a turn. That should get you fairly close. Place a small cutter in the Musclechuck then set up a dial indicator to measure the run out. Rotate the spindle and record the run out. With a magic marker put parallel marks on the body of the Musclechuck and the router spindle. Next loosen the nut and rotate the body of the Musclechuck 90 degrees and again finger tighten the nut. Check and record the run out. If the run out again increases, rotate the body in the opposite direction and continue to check the run out. If the run out begins to decrease, continue to rotate the body in that direction. With decreasing amounts of angle, continue to repeat this procedure until a minimum is found. Then mark the body and spindle so that the next time the Musclechuck is removed and replaced finding the point of minimum run out will not be as tedious. If high accuracy is required, this procedure should be follow every time the Musclechuck is used. I have performed this procedure on many different routers and each one of them yielded different results. I have found that the larger the spindle taper angle, the more critical it becomes to use this procedure.

If one would purchase a device with a very high quality spindle it would be very expensive. Unfortunately, all of these routers are mass-produced and although they are very good, their spindles are not perfect. Usually the spindles contain high and low spots in the ground surface. So, when mounting a collet and then a tool in the collet that extends out two or three inches beyond the spindle, run out can occur. The smallest defect in the spindle can lead to significant run out. I have had to sand the taper of some router spindles in order to get the standard collet to repeat when mounted in the spindle. This doesn’t occur all of the time because some routers are produced with higher quality than others.

Worn bearings can cause not only run out, but in some cases, severe vibration. Many years of use spinning long cutters with heavy side loads is the usual cause for the ware.

When using larger diameter cutters you can use the same procedure to find the angular point of minimum run out with the cutter itself after the Musclechuck has been mounted. The main cardinal rule is, the more connections that are made, the more run out that can occur.

The Musclechuck has an electrolysis nickel coating. This not only protects against corrosion but puts a hard coating on the Musclechuck to prevent abrasive wear on its exterior. However, plating is not an exact science, there are many parameters that can allow an uneven layer to be deposited on the metal surface. We are only talking about .00005 inches at the most but this can lead to some run out. The coating also protects the conical surface against wear so it remains accurate. However the more it is mounted, the flatter it will become due to ware and thereby reduce the high spots.

The bore size has to be able to accommodate several shank sizes. Most ½ inch tool shanks can measure as small as .4990 to .5oo2 inches. Since the Musclechuck has a fixed bore of from .5002 to .5007 inches some run out can occur. A standard collet can expand or contract to accommodate these different sizes so it wouldn’t contribute to run out. However, if the exact size of the tool shank is known, the Musclechuck bore can be made to fit the size within .0002 of an inch. So, if the customer requests, higher accuracy, it can be obtained for a small price difference. Be aware that if the engagement length is approximately 1½ inches, approximately .0002 of an inch is needed to be able to fit the bore. Again if attention to detail is practiced high levels of accuracy can be obtained.

Clamping technique also leads to run out and stability. It takes six points in three-space to define a cylinder. For those of you who are not mathematicians, it can be said another way. In order to draw a three dimensional cylinder or tin can in our three-dimensional world you need two circles of known diameter. Three points on the circle’s circumference define the diameter, hence six points. Lets examine a typical cam chuck. The bore has to be slightly larger than the shank of the tool. When the cam is tightened it pushes the shank of the tool up against the bore of the chuck. So, they come in contact in a single line. The cam tip comes into contact with the tool shank in a single point. A line can be defined in two points, so since there are only three points of contact, the tool shank is free to move around. This can lead to not only run out, but vibration as well. It is known that under severe operating conditions cam chucks have released the tool shank, which leads to unsafe operating conditions.

The Musclechuck does a far superior job of holding on to the tool shank due to several factors. When the Musclechuck is tightened the finger distorts ever so slightly that captures the tool shank circumferentially. The bore is slightly larger as in the case of the cam chuck but instead of all the force being applied at one point, the finger on the Musclechuck intersects the tool shank in several points. This not only allows superior clamping of the tool shank but greater stability as well. So, larger cutters can be used under severe conditions with much more safety. For all you mathematicians out there, when the finger distorts it forms a distorted ellipse on one side while the bore remains circular on the other. Since the tool shank is circular, the tool shank intersects the bore in a line the same as a cam chuck but on the finger side the elliptical surface intersects the tool shank in at least two lines. Therefore there are at least six points holding on to the tool shank, hence the superior griping force. The Musclechuck far out performs any cam chuck and does it without the fear of any damage to the tool shank. We were so impressed with the clamping performance of our chuck, we decided to call it the Musclechuck. 

Of course, the quality of the machined parts is always most important. Musclechucks are manufactured with very high quality cnc machines. They are hand honed to insure accuracy and tested before they leave the factory. This will insure high quality and pride being manufactured in the USA with the finest of materials. I hope this has been helpful and if you have any questions, please don’t hesitate to give us a call.


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## paduke (Mar 28, 2010)

Its amazing the results the manufacturers have achieved Thanks for the work. I had searched for run out on the Web as you did and had few results


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## lenh (Feb 27, 2009)

How does one make adjustments for run out on the muscle chuck with internal threads?


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## Johnd426 (Feb 21, 2013)

Hi Lee, this is John DeRosa owner and inventor of the Musclechuck. I have already sent 
you an email but I also wanted to post the information on the Forum so everyone can
understand what is going on. The problem is getting two solid surfaces to mate along the same line. What I initially do is lightly sand the spindle while the router is running and go through my procedure that is listed on the site 'musclechuck.com' By doing this you can knock off any high spots that were there. When I buy a router to build a chuck
for I usually go to the store and exchange routers until I get one that has less than .002
in of runout and start from there. Just doing that should get you to about .003in of runout. After that continue to play the rotation game and you will find the sweet spot. 
I've managed to get the Milmaukee to almost 0 runout by repeating this process. Since 
you work with metal you understand the imperfections of grinding. I hope this helps you
because there are more parameters that contribute to runout and we can discuss them if you would like. Good luck and please let me know what happens. Best Regards, John D.


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## N'awlins77 (Feb 25, 2011)

Hey John, thanks for getting back to me and for replying here!! Since I've probably now started something (sorry....), you just as well pass the solution on to the masses!! LOL Like I said to you and everyone here, being in the industry that I am in, is sometimes a curse with my hobby. I over think things. I'm not building a wooden rocket ship! But also like I said, I seen someone had a problem with bad run out, and I don't think I'm going to get the time in the wood shop to try this out for some time. So I was just covering the bases. 
Anyway, after the day I had today, I would rather not discuss "run out" for the rest of the day (if not longer). I went on a job today, where a customer bought one of our new lathes (I am a manual machine tool mechanic). They could not get the tailstock of the lathe aligned. (mind you, this is a 40+ thousand dollar machine) They were getting different, all out reading, every time they tried to line up the tailstock with the headstock (eliminate --- run-out, on their part) the numbers would go from almost good, to way out left field. I get there today, thinking to myself, with my 30+ years of experience, I'll knock this out in an hour or less. Dream on... Was there for over 6 hours, and I'm home now, still scratching my head! Will head back there tomorrow. Hoping that "new day", "clean slate", malarkey will work for me!! But yea, I've had about enough of "run-out" talk I can handle today!! 

But John, as soon as I find the time, I will follow your instructions here and on your website and give it a shot. Just don't know when that will be!! Oh, and WELCOME to the Routerforums!!!


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## DaninVan (Jan 1, 2012)

Hey, John; welcome!
You know you're a celebrity here, eh? 
After reading your comments I now have a much clearer idea of why you don't do the Canadian distributorship thing. If you thought it'd be a logistical nightmare, you're probably absolutely right. Still, it'd sure be great if we Canucks had easy access to your products(?)...


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## Nickp (Dec 4, 2012)

Lee..."new day, new way" has a requirement for a secret ingredient...

My buddy Tommy and spent hours trying to slip a set of headers into his "409" without jacking the engine...we stopped, took out the "secret ingredient" ( six pack) and as I was making another attempt I dropped the header and, assisted by a warp in the space-time continuum, it fell into place on its own...Tommy and I looked at each other and vowed never to disclose the secret...

Have a better day today...

Nick


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## N'awlins77 (Feb 25, 2011)

Nick, it works every time. I was there about 2 hours and had the problem licked. Not counting it was the only thing on my mind, the whole night, and then some!!! LOL But yea, I got'er fixed up this morning. The customer is thrilled and I'm even thrilledededed!!! Whew... 
On to the next headache!!


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## Nickp (Dec 4, 2012)

N'awlins77 said:


> Nick, it works every time. I was there about 2 hours and had the problem licked. Not counting it was the only thing on my mind, the whole night, and then some!!! LOL But yea, I got'er fixed up this morning. The customer is thrilled and I'm even thrilledededed!!! Whew...
> On to the next headache!!


Good to hear...thanks for the update...


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