Thomschuck
Fellow Geniuses,
I have had an on going issue with my 1983 Mark V 500. We have a fellow member that has a brand new Mark 7 PowerPro Plus that is dealing with the same issue on his new machine.
The problem stems from what I describe as blade wobble. On my machine when the blade slows you can actually see where the blade does not swing true. It appears to wobble. I just had my headstock completely rebuilt. It has a single bearing quill that was rebuilt. I also bought a new 5/8th arbor. I noticed the blade movement on day one. Knowing the machine was solid I thought I had a bad arbor. I bought a new arbor. I still have what looks like a wobble. We tried several different blades. I still have what looks like a wobble. We put the machine in drillpress mode and installed a brad point bit. It Drilled straight and true. Zero bit walk or knock with a brad point or a forstner drill bit. I gave up. It is what it is.
I have been helping a new member along with his new 7 PP+. He is experiencing the exact issues that I have. Like me he bought a new arbor. Like me he has tried multiple blades. He describes his wobble issue exactly the same as mine. EXACTLY! Our fellow member is genuinely frustrated with what is obvious to the eye. That blade is not true. I could add more words but it would be blah blah blah. I/we are open to any thoughts ideas or criticism on the issue of what appears to be blade wobble. Ideas PLEASE!
wa2crk
Is the blade warped? Are you tightening the arbor nut correctly? Did you try a different arbor? The fact that you can drill OK with different style bits indicates that you do not have a headstock problem. The problem most likely has to be in what is being attached to the quill shaft and the methodology used to attach the components. One other thing is that the arbor mounting hole has been drilled at an angle rather than straight into the arbor. The accurate drilling suggests strongly to me that you have some kind of a funky arbor.
Bill V
PS You mentioned another member. Is he a member of this forum? If so please have him check in here to add to this discussion. Also what is your location? We may have someone close to you who can help.
Thomschuck
Correction noted!
Both machines each have a new arbor. Bought by both users to confirm if our original arbors were bad. Second, on my machine we ran 4 different blades. My machine = 2 Arbors, 4 different blades. I bought a brand new arbor from ShopSmith to try and correct the issue. New Arbor and 4 blades later the problem is exactly the same. Me? I live in Portland Oregon.
YES! The other owner with the M7 PP+ Is a member on the forum. He bought a new ShopSmith arbor to null out the wobble issue. That did not work. He then bought a very nice Uber high quality blade. He still has a wobble. All new gear to the quill shaft and my 35 year old machine responds just like his new M7PP+.
Trust me, I have spent hours looking and thinking about this issue. On my machine everything is new or rebuilt.
Thank You!
dusty
How wide of a blade do you have and how wide is the kerf that it cuts?
If you have wobble, the kerf will be wider than the blade.
Can you measure shaft run-out with the arbor removed?
jsburger
Thomschuck wroteCorrection noted!
Both machines each have a new arbor. Bought by both users to confirm if our original arbors were bad. Second, on my machine we ran 4 different blades. My machine = 2 Arbors, 4 different blades. I bought a brand new arbor from ShopSmith to try and correct the issue. New Arbor and 4 blades later the problem is exactly the same. Me? I live in Portland Oregon.
YES! The other owner with the M7 PP+ Is a member on the forum. He bought a new ShopSmith arbor to null out the wobble issue. That did not work. He then bought a very nice Uber high quality blade. He still has a wobble. All new gear to the quill shaft and my 35 year old machine responds just like his new M7PP+.
Trust me, I have spent hours looking and thinking about this issue. On my machine everything is new or rebuilt.
Thank You!
What is YOUR definition of wobble? You stated in your original post ...
"On my machine when the blade slows you can actually see where the blade does not swing true."
What does that exactly mean? Does the blade cut true at speed? If so then are you seeing an optical illusion at slower speeds?
Different machines, different arbors, different blades none of this makes any sense.
garys
Blade wobble is supposedly one of the reasons that Shopsmith makes their blades with 1 1/4" diameter holes. Common sense says that the larger the mounting point of the blade, the less it will distort and wobble. It might work that way, but even the larger arbor might not be able to eliminate all wobble in the blade.
Does the wobble seem to affect the cuts you make with the saw? If not, then it doesn't matter. If you get poor or too wide cuts, then it might be worth pursuing farther.
Thomschuck
Thank you for your replies.
Read this part please! I have tried every combination in the book to get my blade to run true.
Define wobble.... When my blade slows down it is not in a straight edge line. I put a Starrett scale Up against the blade so it is touching. I turn the blade with the SPT PTO. It no longer touches the blade. Like the blade is bent. Four bent blades, no way. One is a brand new Forrest blade.
I put a thin kerf Systematic blade on the machine. I made a cut into a piece of Walnut stock. I measured the cut. YES it’s wider than the kerf on the blade. I put on a brand new Forrest blade and measured that cut. It’s slightly wider than the kerf on the blade, but not much. It is almost like the blade is being mounted at an angle. If you listen to the blade you can hear the blade make contact then no noise, then contact, then no noise. Maybe one tweaked blade but not 4. maybe a bad arbor, but not two, one being brand new. Then in talking to Bill a new member with the M7 PP+ I discovered he is struging with the same issues. I know, WEIRD. Help? My question is define run out? I know play and I know runout. Note. It’s a very symmetrical problem.
sehast
If you have a sanding disk try it and see if you get the same results. The larger diameter should amplify the wobble if it is due to the quill and you will have eliminated any arbor issues. I think you have already eliminated the blades as the problem.
bainin
Is the table absolutely true to the blade?
If I press on my main table when its is only 2 post supported, it does have some movement if it is not supported by the
auxiliary table/legs. Is it possible the main table has some movement rather than the blade?
b
Dansmith
Do you have a dial indicator that you can use to measure runout, if any, of the bare spindle?
StevenAyres
I'm not saying I know what the answer is, but I notice that no one has yet mentioned the possibility of play in the arbor mount. If the bore is larger than the spindle diameter, the setscrew will pull the arbor a little off center, possibly at a slight angle.
The fit of the spindle should be tight enough that when mounting a chuck, you get some air resistance before it will push all the way on the spindle.
I was mounting a new blade on my brownie this weekend, and noticed the sort of symptom described in the OP. I took it down again and flatted the spacers, making sure they were really clean on all bearing faces. It helped. I don't expect this is the answer here, either, but it's a tip to keep in mind.
Hobbyman2
I had the exact same experience when I got my'n , here is what I did with the process of elimination, first I checked the blade for flatness , laid it on a flat surface , a table from a table saw will usually be god enough, maybe a work bench , a machined piece of granite is what I used , but they are not cheap . next step is to put a bit in a drill chuck and check to see if it starts perfectly or if the tip cuts in a orbital manner, if it doesn't check for run out on the main shaft , if it spins true then the last thing in the system wold be the arbor ? I can tell you that I went with the double bearing quill and it has made a huge difference in the shaft movement , however when I tighten the arbor to the quill it does add a small amount of distortion to the blade cut , I assume that is normal do to a .000 or so in the arbor its self , it will not be as accurate as a blade attached directly to a shaft as on a dedicated table saw . I have a question that may or may not be related , does the hight of the blade change any when it spins?
unplug it , install a blade set the depth of cut , slowly turn the blade . does the hight stay the same ? is there any variation in the height of the teeth ? I ask this because any thing that can alter the balance of the blade will change its performance just like a car tire ? Good luck ,don't give up , I set my mkv into thee lathe position , set the center point to point , spin the shaft , the centers should stay point to point on a precision machine .
Good luck
JPG
A 'perfectly' flat blade is elusive.
I have not seen a number that would reveal the amount of 'wobble'.
Same problem with two different machines MAY indicate a setup problem with both.
Are you both centering the set screw on the quill shaft flat by rocking the arbor rotationaly to place the set screw at the lowest point on the shaft?
The sanding disk MAY provide clues, but they are not perfectly flat either.
Also are there burrs on the quill shaft. Look at the edges of the flat.
wa2crk
Do you have a friend who has a table saw that is not a Shopsmith. If you do take your best blade and try it in his table saw. If it runs true, then the problem has to be in the arbor. When you loosen the set screw on the arbor you should hear a "pop" when the arbor comes off the quill shaft.
Is the arbor and the arbor nut machined true or is the nut machined at an angle from one side to the other.(different thicknesses) Do you have a universal work arbor to mount the blade to. If so mount the blade to one of the universal arbors. If you have the shaper arbor it would be a good one to use. Mount the blade to see if still has the wobble but DO NOT USE THE UNIVERSAL ARBOR AND BLADE TO CUT ANY STOCK!!. You are just checking to see if the blade runs true. What is confusing to me is that when you mount the drill chuck and drill holes the drilling runs true. At this point I would check the diameter of the hole in the arbor that the quill goes into and see if there is any play or wobble before you tighten the set screw. If there is then the arbor is still suspect. Also check to see if the hole in the arbor is machined at a right angle to the plane of the blade.
Bill V
Hobbyman2
I would think the pressure washers would absorb any distortion in the threads? am I incorrect ?
reible
How about a movie of the blade doing its wobble?
My guess is that what you are seeing is the result of harmonic vibration. I would make sure the quill lock is tight, the head stock lock is tight and the machine is setting on the floor.
Blades especially cheaper ones are not going to be all that flat. The more expensive blades will be better but then even they will be off by a couple of thousands(.002'-.003") And the teeth angles will also effect what you see as the blade is in transition. The best blade to view would be a rip blade with flat ground teeth, all others could be playing tricks on your eyes.
Dusty suggestion is good if the machine is in perfect alignment, the kerf should be really close to the blade width but make sure you are using the miter gauge and have it set right for a straight cross cut.
Gut feeling is that you really don't have a problem but if you want to do some more testing then we need to start using some scientific principles. I would also not rule out a bent quill shaft, new bearing with a bent shaft is still a bent shaft.
The easy way to test the shaft is to move the arbor and blade to the other end of the headstock. DONOT run the blade there but you can do some measurements to see if it is better there on another shaft. If it is then it would point to a bent shaft.
If nothing changes then move back to the proper location and we can do some more testing there:
Mark the arbor, and the blade and if you have a gauge take readings 90 degrees apart around the blade out near the rim of the blade for a fixed location on the main table. Loosen the blade and rotate just the blade about half way round (180 degrees) and tighten. Now repeat the measurements. It should be clear if the numbers are following the blade or the arbor/headstock. If you don't have a good gauge for this then we can go another way but this would be instructive.
Enough for tonight.
Ed
Hobbyman2
One way to find out is to make a cut then measure the width of that cut with a shim or something that is accurate.
I also wonder if the blade deviates when under cutting pressure ? my'n did ,it was impossible to make a accurate dado cut .
Using the miter gage and hex wrench or a mic set to the blade face use a piece of stock and push against the blade and watch for movement ?
If the blade doesn't cut properly it can be a issue with blade burning and kick back.
What has me concerned is a new machine " MKVII PP"doing this as well, that leads me to believe the issue is in the arbor,, at least on the MKVII PP ???
JMO
billdvorak
I have been using a cheap dial gauge. I use it for the fence every time and blade and table sometimes. I get very consistent results and measurements the bare arbor around .002 out.
billdvorak
Yes on kickback and burning with new blade and arbor
billdvorak
I’m the new guy in case it isn’t obvious. I will try to get a video of the wobble if someone can tell me how to post it.
