No Weld Grinder Frame Kit shaft/pillow block alignment problems

[duffy99]

No Weld Grinder Frame Kit shaft/pillow block alignment problems/contact wheels?

Hi I've been searching hi and low for help with alignment issues on the NWG Frame Kit . Since this is Tracy's forum hopefully some experienced builders can help me . I went with a 3/4" shaft and NSK pillow blocks since I got a used 3/4" shaft KMG drive wheel for free a few months ago. The shaft is from fastenal and is


"Shafts are made from 1018 steel and are supplied fully keyed the entire shaft length. Key Depth tolerance is +.010/.000. Key Width Tolerances is +.002/-.000. Straightness tolerance is 0.012 per foot"

I assembled it all and it's run by a 2 hp motor with VFD with a one to one ratio pulley. When I fired it up the wheel seemed to wobble with each rotation . The wheel is used and I have it with the heavier side out , the other side is recessed to the midpoint of it . When I square the pillow blocks to the end of the base tube the drive wheel is visibly angled outward so I aligned the shaft for the wheel to be in line with the frame .


So basically whats the best way to align the pillow blocks and shaft, second would misaligned pillow blocks cause a wobble per rotation or is it the wheel or shaft . I've rolled the shaft and lined it up with a 5/8" shaft provided with the kit and there isn't a visible bend . Could the pulleys cause this or is it either the wheel or the shaft or misalignment of the shaft in the pillow blocks ? Any advice would be greatly appreciated .


Pic of recessed side of wheel

 

[Rudy Joly]

First...how good is the free wheel ? Was it dropped, any flat spots ?

This is tough with pictures but your pillow blocks don't look aligned. ( I COULD be wrong) To check that, I'd remove the drive belt, loosen the inside pillow block so it floats a little and spin the drive wheel by hand while keeping a wrench on the bolt to tighten it when you see no movement in the loose pillow block. This will only work if the outside bearing is truly square to the machine. You may need to reverse the proceedure. Next, those 1018 shafts are notoriously untrue. Take off the drive wheel and spin the shaft between the the blocks, looking at the end of the shaft, check for any oblong movement. A dot from a sharpy on an outside edge helps. Check the pulley too, although if it's a cheap pulley it will probably spin oblong. Lining up the drive wheel with the frame isn't neccessarily the right thing but it's a starting point. There's lots of variables. I'd be suspect of a free wheel first and then the shaft. Good luck.

Rudy

 

[rob45]

A variety of things could be causing your problem.

Hard to tell without being there, but in your second photo, it appears that the fit of the driveshaft to the bearing may need to be checked.
But that could just be an optical illusion due to either the photography or my poor vision.


"Start from the ground up". Sorta like building a house, it all starts at the foundation.

We're not building precision machinery per se, but minimizing tolerances at each step helps prevent the compound errors that may have us scratching our heads later on.

Here are a few ideas.

1. Check the shaft for straightness and roundness.
I was taught to use v-blocks and a dial indicator, but I'm not sure if that's needed for our purposes. Maybe, maybe not.
You mentioned that you rolled the shaft and visually compared it to another shaft. The visual comparison to another shaft doesn't really tell you anything other than one shaft appears as "straight" as the other- it doesn't prove they are both straight.
The rolling test is simple and reliable enough providing your test surface is as flat as the tolerances you need to hold. Rolling on the typical benchtop is where a lot of people think they are using a flat surface, only to be surprised when it is properly checked. If you want to use the benchtop as a flat surface to roll, it's best to use a good straightedge to check the surface for flatness.
A granite surface plate is a reliable surface for the roll test; a piece of plate glass is (usually) flat enough, too.
Or whatever surface you trust to be the flattest available to you.
With all that said, purposely-built shaft material is normally straight enough for our needs. But every manufacturer has boo-boos, and who knows what can happen between the time it leaves the manufacturer and finally gets to you.
At any rate, it's best to check the shaft for straightness. The shaft itself is the "foundation" of it all, and any other testing is pointless if the shaft is not already straight enough for your needs.
Another thing to watch for is a shaft that's out-of-round. Again, seldom will you have one that's bad enough to cause problems, but you never know. In particular, I've had some shafts with full-length keyways that were not as round as I would like.
The simple tests used to check straightness can also usually give enough of an indication concerning roundness.

2. Check for concentricity.
A more common problem with shafting is closely matching the shaft diameter to the bearing bore. This was mentioned above, and it is an area often overlooked.
The shaft itself may be straight and round, but it can be forced to rotate in an eccentric manner. In other words, the center of the shaft does not line up with the center of the bearing.
Due to the nature of our construction and the parts we're using, obtaining perfect concentricity is very rare. That's OK; it's not like we're building a CNC machine. But we should strive to minimize tolerances here, because loose tolerances translate into compounded errors later on.
Some types of bearings have opposing setscrews to help alleviate an improperly-fitting shaft. The idea is to move the screws on each side further in/out to help center the shaft in the bearing. I have no experience with these types, but the same concept is used in lathe chucks.
Personally, I would rather have a good fit to begin with.
A good way to check if this is an issue is to use a dial indicator to check for excessive runout of the shaft while it's mounted in the bearings. This is based on the premise that you have already checked the shaft itself for acceptable straightness and roundness.
If you don't have an indicator (even the cheapies will work for this), you could eyeball it like Rudy described. It's better than not checking at all.
Something else to consider is that, although rare, it's possible to obtain a defective bearing. I remember one time when I actually measured the shaft and the bearing bore. "According to the numbers" (yeah, right, we all know how that can go:les it should have been a nearly perfect fit, and it was indeed tight. The problem was not the fit; it was the bearing itself.
But even after that experience, I still wouldn't jump to conclusions and suspect the bearing, especially if it was of reputable manufacture.

3. Mounting/alignment
I don't think mounting inaccuracies are causing your "wobbling" problem, but you never know...
Two types of alignment you're dealing with here: a). the alignment of the bearings to the shaft, and b). the alignment of the shaft to the rest of the machine.
a). I have been told that the type of bearings being used in this application are designed to accommodate slight variances in angular alignment.
Naturally, you should try to keep the bearings as square to the shaft as possible, but if the shaft turns freely in the (mounted) bearings, you should be OK as far as alignment of the bearings to the shaft is concerned.
b). The alignment of the shaft to the rest of the machine is primarily done to ensure the grinding belt rides properly. If the shaft is squared to the frame, then you have a good baseline to align the other wheels in the system (tracking and idler wheels, etc.) to make everything coplaner.
But your problem is wobbling of the drive wheel itself, and I don't see where this type of misalignment would contribute to that.

4. Drive wheel
If steps 1 & 2 check out OK, the next thing to suspect is the drive wheel itself, especially if it has an unknown history.
Rudy hit the nail on the head concerning this.
Use the dial indicator to check the wheel the same way that you checked the driveshaft. (As always, make sure the indicator is firmly mounted.)
In the abscence of an indicator, a spacer block and set of feeler gages might work.
Many things can contribute to a "bad" wheel, but at least by this point you should be able to tell if it's the wheel or something else.

5. Sheave (pulley)
The pulley can be checked in the same manner. It's not at all uncommon to have it out-of-round, eccentric, or whatever.
But with the design of your mounting system, the chances of a "bad" pulley causing your drive wheel to wobble seem very slim.
The shaft is solidly mounted in the bearings, which are anchored to the frame.
The (pulley) belt is the "weak link" in the design to first absorb the stresses caused by an out-of-spec pulley.
The belt will wear, the groove in the pulley will wear, and the bearings will wear.
Excessively worn bearings could potentially translate into wobble on the other end, but you're having a wheel problem with fresh bearings right out of the gate; if the sheave were the culprit, it hasn't had a chance to affect your bearings yet.

 

[duffy99]

A variety of things could be causing your problem.

Hard to tell without being there, but in your second photo, it appears that the fit of the driveshaft to the bearing may need to be checked.
But that could just be an optical illusion due to either the photography or my poor vision.


"Start from the ground up". Sorta like building a house, it all starts at the foundation.

We're not building precision machinery per se, but minimizing tolerances at each step helps prevent the compound errors that may have us scratching our heads later on.

Here are a few ideas.

1. Check the shaft for straightness and roundness.
I was taught to use v-blocks and a dial indicator, but I'm not sure if that's needed for our purposes. Maybe, maybe not.
You mentioned that you rolled the shaft and visually compared it to another shaft. The visual comparison to another shaft doesn't really tell you anything other than one shaft appears as "straight" as the other- it doesn't prove they are both straight.
The rolling test is simple and reliable enough providing your test surface is as flat as the tolerances you need to hold. Rolling on the typical benchtop is where a lot of people think they are using a flat surface, only to be surprised when it is properly checked. If you want to use the benchtop as a flat surface to roll, it's best to use a good straightedge to check the surface for flatness.
A granite surface plate is a reliable surface for the roll test; a piece of plate glass is (usually) flat enough, too.
Or whatever surface you trust to be the flattest available to you.
With all that said, purposely-built shaft material is normally straight enough for our needs. But every manufacturer has boo-boos, and who knows what can happen between the time it leaves the manufacturer and finally gets to you.
At any rate, it's best to check the shaft for straightness. The shaft itself is the "foundation" of it all, and any other testing is pointless if the shaft is not already straight enough for your needs.
Another thing to watch for is a shaft that's out-of-round. Again, seldom will you have one that's bad enough to cause problems, but you never know. In particular, I've had some shafts with full-length keyways that were not as round as I would like.
The simple tests used to check straightness can also usually give enough of an indication concerning roundness.

2. Check for concentricity.
A more common problem with shafting is closely matching the shaft diameter to the bearing bore. This was mentioned above, and it is an area often overlooked.
The shaft itself may be straight and round, but it can be forced to rotate in an eccentric manner. In other words, the center of the shaft does not line up with the center of the bearing.
Due to the nature of our construction and the parts we're using, obtaining perfect concentricity is very rare. That's OK; it's not like we're building a CNC machine. But we should strive to minimize tolerances here, because loose tolerances translate into compounded errors later on.
Some types of bearings have opposing setscrews to help alleviate an improperly-fitting shaft. The idea is to move the screws on each side further in/out to help center the shaft in the bearing. I have no experience with these types, but the same concept is used in lathe chucks.
Personally, I would rather have a good fit to begin with.
A good way to check if this is an issue is to use a dial indicator to check for excessive runout of the shaft while it's mounted in the bearings. This is based on the premise that you have already checked the shaft itself for acceptable straightness and roundness.
If you don't have an indicator (even the cheapies will work for this), you could eyeball it like Rudy described. It's better than not checking at all.
Something else to consider is that, although rare, it's possible to obtain a defective bearing. I remember one time when I actually measured the shaft and the bearing bore. "According to the numbers" (yeah, right, we all know how that can go:les it should have been a nearly perfect fit, and it was indeed tight. The problem was not the fit; it was the bearing itself.
But even after that experience, I still wouldn't jump to conclusions and suspect the bearing, especially if it was of reputable manufacture.

3. Mounting/alignment
I don't think mounting inaccuracies are causing your "wobbling" problem, but you never know...
Two types of alignment you're dealing with here: a). the alignment of the bearings to the shaft, and b). the alignment of the shaft to the rest of the machine.
a). I have been told that the type of bearings being used in this application are designed to accommodate slight variances in angular alignment.
Naturally, you should try to keep the bearings as square to the shaft as possible, but if the shaft turns freely in the (mounted) bearings, you should be OK as far as alignment of the bearings to the shaft is concerned.
b). The alignment of the shaft to the rest of the machine is primarily done to ensure the grinding belt rides properly. If the shaft is squared to the frame, then you have a good baseline to align the other wheels in the system (tracking and idler wheels, etc.) to make everything coplaner.
But your problem is wobbling of the drive wheel itself, and I don't see where this type of misalignment would contribute to that.

4. Drive wheel
If steps 1 & 2 check out OK, the next thing to suspect is the drive wheel itself, especially if it has an unknown history.
Rudy hit the nail on the head concerning this.
Use the dial indicator to check the wheel the same way that you checked the driveshaft. (As always, make sure the indicator is firmly mounted.)
In the abscence of an indicator, a spacer block and set of feeler gages might work.
Many things can contribute to a "bad" wheel, but at least by this point you should be able to tell if it's the wheel or something else.

5. Sheave (pulley)
The pulley can be checked in the same manner. It's not at all uncommon to have it out-of-round, eccentric, or whatever.
But with the design of your mounting system, the chances of a "bad" pulley causing your drive wheel to wobble seem very slim.
The shaft is solidly mounted in the bearings, which are anchored to the frame.
The (pulley) belt is the "weak link" in the design to first absorb the stresses caused by an out-of-spec pulley.
The belt will wear, the groove in the pulley will wear, and the bearings will wear.
Excessively worn bearings could potentially translate into wobble on the other end, but you're having a wheel problem with fresh bearings right out of the gate; if the sheave were the culprit, it hasn't had a chance to affect your bearings yet.

Thanks for all the advice , the person I got the used wheel from is a well known bubble jig maker and I asked him about the wheel yesterday and he told me he replaced it to go with a 6" wheel from 4" and doesn't think the wheel is the issue . The pulley on the motor is new as is the motor but it appears to be not round and I'm going to replace it today . I'm using power twist belt and when I fired it up yesterday after re squaring the pillow blocks I could here a clicking noise coming from the pulley or pillow block . I tore down the pulleys , pillow blocks, shaft and wheel so I'm at start point again. The shaft had a scratch from one of the locking screws almost half way around the shaft. I think the shaft is suspect. Anyone know were to buy a new one from a local source, I live in Edmonton and it has every type of store most major Canadian cities do. Also would extending the distance of the pillow blocks from being close on the 4" square tubing out more by adding a plate on top help. As there is a 6" or so distance from the pillow block to the drive wheel.

 

[rob45]

Thanks for all the advice , the person I got the used wheel from is a well known bubble jig maker and I asked him about the wheel yesterday and he told me he replaced it to go with a 6" wheel from 4" and doesn't think the wheel is the issue . I understand what you're saying. The wheel may or may not be an issue, and the only way to know for sure is to follow the progression of tests mentioned. If it does indeed turn out to be a defective wheel, that does not necessarily mean the person told you wrong, as I have had parts get messed up simply by poor handling during shipment.
The pulley on the motor is new as is the motor but it appears to be not round and I'm going to replace it today . I'm using power twist belt and when I fired it up yesterday after re squaring the pillow blocks I could here a clicking noise coming from the pulley or pillow block . Try to determine if the noise is coming from the belt or the bearing. Disconnect the belt and spin the shaft in the bearing. If you get noise, the bearing(s) is suspect. If the bearing checks fine, the belt could be making the noise. Belts by their very nature are gonna make some noise, but any noise considered abnormal could range from the belt simply not being "broke in" to an out-of-spec pulley groove. Or perhaps the motor pulley is not in line with the drive pulley.
Whatever the cause, try to determine if the noise is due to the bearing or the belt.
I tore down the pulleys , pillow blocks, shaft and wheel so I'm at start point again. That's good, because now you can test each area as the machine is put together, following the "foundation" approach.
The shaft had a scratch from one of the locking screws almost half way around the shaft. I think the shaft is suspect. Anyone know were to buy a new one from a local source, I live in Edmonton and it has every type of store most major Canadian cities do. I can't tell you a local source, but whether you buy locally or have it shipped to you, check it out before installation.
Also would extending the distance of the pillow blocks from being close on the 4" square tubing out more by adding a plate on top help. As there is a 6" or so distance from the pillow block to the drive wheel. Absolutely. See my thoughts on this below.

Many people have used the "plate trick" as a part of their construction. The idea is to get the bearings, which serve as the anchoring point, closer to the driven part (pulley or wheel).
Consider that you're attempting to keep your runout at the wheel hopefully less than a few thousandths of an inch.
The supplier of your shaft says the straightness tolerance is .012"/ft. You have half that distance to cover (6"), so theoretically your shaft straightness tolerance is now within .006".
Dealing with numbers this small make it hard to see when doing a roll test on the shaft, but a dial indicator will easily tell. In addition, it becomes even more visually evident when you put that wheel/sheave on the shaft.
Even if you have the straightest shaft in the world, the extra support closer to the driven part is always a welcome addition. Both the bearings and the shaft will thank you in the long run.
Don't skimp on the steel used for this; the thicker the better. I'm not saying you have to use a 2" solid chunk of steel; just don't use something "flimsy" like 1/8". This is the anchoring point for the bearings. Mass is your friend here.

 

[duffy99]

I've come to the conclusion that the shaft isn't straight and also the wheel is also out of round . Also the threaded holes on the base tube aren't at very high tolerances to the base ( confirmed by supplier) but was told the bearings self align to alleviate this .So when pillow blocks are tightened their not both square to the base tube which is assuming that the end of the 4x4" base tube is straight and none of the sides are deformed which is unlikely due to the material . I am using a 3/4" shaft and 4" drive wheel but have the 5/8" shaft and pillow block bearings that came with the kit . I just ordered a 5/8" bore 6" drive wheel but it's 2 weeks back ordered + shipping . I'm running with a 2 hp 3 phase and VFD so the bigger wheel shouldn't be an issue speed wise and I can always use it in some direct drive application since the motor shaft is 5/8" and 56C with a removable base mount .

The sheave on the motor when running without a belt looks out of round but I got a replacement today , I hope it's the sheave and not the motor shaft since the motor is out of the box new. I'm just wondering how much force is being placed on the motor shaft and drive shaft when you add the drive wheel and tension of the belt . I think the tension of the drive belt is the lateral force applied to the motor shaft and the tension + weight of the drive wheel is the force applied to the drive shaft with the bearings in the pillow blocks taking the force load , correct? . How much lateral force can the parts take without deforming . Due to the design and parts of this grinder is it really possible to get belts tracking perfect and smoothly without any side to side movement at all . As it is now the grinder isn't unusable but far from where I want it to be , I guess I'll just have to wait for the new wheel and hope using new pillow blocks, shaft and wheel will smooth it out .

I'm still debating adding a plate on top to the base , I have some square tubing in 2"/1.5"/1" some 1/4" mild steel plate and 1/2" x 1" x 13" mild steel bar and even some 3/8" thick aluminum plate . I have a tap/die set , wobbly drill press, 2x42 belt grinder and even a little gas less mig welder but I suck at fabricating stuff which is why I chose to buy the Frame Kit in the first place instead of just building it.

 

[rob45]

Let me think this info over and reply tomorrow morning. Gettin' ready for a double at work.

Trying to think about how to present it so as to cover all the bases without having a mile-long post (because I type slowly).

 

[duffy99]

I also got a dial indicator which I used to confirm the run out of the shaft and the wheel.

 

[rob45]

I've come to the conclusion that the shaft isn't straight and also the wheel is also out of round . OK, so at least we're getting somewhere. Remember the shaft is the first thing that has to check out OK. It does you no good to say anything else is at fault unless you have already proven the shaft is suitable.

Also the threaded holes on the base tube aren't at very high tolerances to the base ( confirmed by supplier) but was told the bearings self align to alleviate this .So when pillow blocks are tightened their not both square to the base tube which is assuming that the end of the 4x4" base tube is straight and none of the sides are deformed which is unlikely due to the material . That's what I was talking about before. Pillow block bearings are designed for applications like this. They will accommodate slight amounts of angular misalignment. I can't say for certain, but my belief is that if installed with the small misalignment, the bearings "break in" that particular spot within the race. The real problem starts whenever you take things apart and do not put the bearings back into the original position, because now you're asking them to ride within the housing differently than what they have worn into. This may just be one of my own beliefs, but that is when I have had bearings suddenly go south on me for no other reasonable explanation. So I always like to reinstall the bearings back in the original position and orientation.
If you feel the misalignment is too much to your liking, then installing the extra plate (to space the bearings farther apart) is an ideal time to correct the misalignment. That way you'll be knocking out two birds with one stone.

I am using a 3/4" shaft and 4" drive wheel but have the 5/8" shaft and pillow block bearings that came with the kit . I just ordered a 5/8" bore 6" drive wheel but it's 2 weeks back ordered + shipping . I'm running with a 2 hp 3 phase and VFD so the bigger wheel shouldn't be an issue speed wise and I can always use it in some direct drive application since the motor shaft is 5/8" and 56C with a removable base mount . Nothing wrong with choosing to use a 6" wheel for your setup. It's an excellent way to get those higher surface speeds that eat metal quickly, and you've got the motor power to back it up.
Just gotta make sure everything before the wheel is making it spin correctly.
If the shaft isn't straight, all is for naught.
Likewise, if the shaft doesn't fit reasonably snugly within the bearing, you could still have problems no matter how straight the shaft and how good the wheel.
This is why I was asking earlier about the shaft fit. Often people will have a loose fit and not even think about it because they have a keyway or setscrew to "lock things down". With the myriad of specs and tolerances out there by different manufacturers, it's easy to see how this area, which is often taken for granted, is overlooked.

The sheave on the motor when running without a belt looks out of round but I got a replacement today , I hope it's the sheave and not the motor shaft since the motor is out of the box new. You would check runout on this in the same manner that you use to check the driveshaft assembly. First check the motor shaft, then check the runout on the pulley. See more about this below.

I'm just wondering how much force is being placed on the motor shaft and drive shaft when you add the drive wheel and tension of the belt . I think the tension of the drive belt is the lateral force applied to the motor shaft and the tension + weight of the drive wheel is the force applied to the drive shaft with the bearings in the pillow blocks taking the force load , correct? . How much lateral force can the parts take without deforming . I have access to a calculator that can determine all of this, but it gets pretty "hairy".
To make a long story short, if you have all components spinning properly, then the only two concerns you should have are a.) excessive sheave belt tension, and b.) excessive driveshaft speed. If everything is within specs, this design can easily handle the loads involved.
Due to the design and parts of this grinder is it really possible to get belts tracking perfect and smoothly without any side to side movement at all . Yes, it is very possible. This is a solid, proven design. As with nearly all items of this nature, there is often a myriad of "little things" we can improve. But the basic design of this is without question very good.

As it is now the grinder isn't unusable but far from where I want it to be , I guess I'll just have to wait for the new wheel and hope using new pillow blocks, shaft and wheel will smooth it out .
Some of us don't get quite the good luck that others may; I know because I've been there on a few projects.
The best thing to do is know the things that can cause a specific problem and how to correct it. I have been guilty of falling into the trap of throwing money into several new parts, only to find out later that the least expensive item was what actually caused the problem. Other times it really was more than one part that caused the problem.
The best investment I ever made for any of this stuff was the testing/measuring/setup tools and learning how to use them.

I'm still debating adding a plate on top to the base , I have some square tubing in 2"/1.5"/1" some 1/4" mild steel plate and 1/2" x 1" x 13" mild steel bar and even some 3/8" thick aluminum plate . Whatever you use, it's probably best to brace underneath the mounting point for the bearing housings. The frame tube is 4". On mine I used a couple of short leftover pieces of 4" tubing. Placed them right where the bearings were sitting, and used a piece of 1/4" flat stock layed across. The point is to have a solid anchor where the bearing sits.

I have a tap/die set , wobbly drill press, 2x42 belt grinder and even a little gas less mig welder but I suck at fabricating stuff which is why I chose to buy the Frame Kit in the first place instead of just building it. That's OK; I consider myself to be a pretty poor fabricator, too.
But over 20 years ago I decided I was gonna build a huge buffing station for my (then) business instead of paying the big money for the industrial unit. Then came the resaw. Then the drum sander. On and on.
After all this, I still don't own a welder.
But I know how each machine works, what it needs, and have a fair idea of what's worth building vs. buying. This machine is worth building, even if it is in kit form.

Regarding your concern about the motor shaft and sheave, approach it the same way you do the driveshaft, bearings, and drive wheel.
First measure radial runout at the motor shaft. Be sure to use the far end of shaft for the measurement.

If the motor is fine, make sure the clearance for shaft to pulley bore is correct. Standards vary among manufacturers, but here is what works well for me:
For a 2" sheave, clearance should be 0.0000" to +.0015".
For a 2-3" sheave, your clearance can go up to +.0020".
For sheaves larger than 3", clearance can go to +.0025".
Obviously the tighter the clearance the better. By the way, these numbers aren't from me; they were a suggestion from a rep at a drive products manufacturer when I was chasing down the same types of problems you're having.
Roughly put, if you can easily slide the pulley on the shaft and then be able to wiggle the pulley before you tighten the setscrew, you already have excessive clearance.

After you have confirmed bore fit of the sheave to the shaft, install the sheave on the shaft and check radial runout on the sheave. Quoting from the same manufacturer, your eccentricity should fall within these guidelines:
If your sheave diameter is up to and including 2", your total indicator reading should be .0025" or less.
If the sheave is over 2" up to and including 4", your max TIR can go up to .003".
For sheaves over 4", your TIR can go to .004". This is for sheaves up to 8" diameter.

Now, let me state this: Only you can decide how critical it is that you stay within "recommended" tolerances.
Many people "slap together" one of these machines and are either lucky enough to be within recommendations without even checking, or maybe they're "outside of tolerances" but don't even know it, yet they're perfectly happy with what they've built. That's probably most of us.
Others want maximum smoothness and parts life from their unit, and they'll measure everything on the machine and leave nothing to chance.
As an example, the drum sander I built does not use pillow block bearings; it uses bearings pressed in place. Disassembling the machine to replace a bearing is not a simple matter of loosening the bolts on the pillow block and sliding the bearing off the shaft, so I checked everything possible.

But at least the above figures give a baseline you can work with.

I think this is a case where maybe you might have just gotten unlucky with a part(s).
Hang in there, by the time it's all said and done you'll know more about what makes your machine tick than the average individual, which is as it should be.

Good Luck,
Rob

 

[duffy99]

Thanks for taking the time for all the advice , I still haven't made the base as I was busy with mid-terms ( I'm a 30 year old 1st year university student after spending 12 years as a Paratrooper/Infantryman in the Army). Another thing I noticed was the tool arms when tightened in place are angled out and / due to the loose fit of the tubing , I was wondering what others have done to fix this . Also is there a way to alleviate loose tolerances of drilled holes for contact wheels giving excessive movement when trying to mount them straight other then drilling new holes in the platen attachment . Like the hole is just slightly larger then the 1/2" bolts, the 2" contact wheel is being mounted onto 1/2" thick steel on the platen . I'm just trying to achieve proper alignment all the way through.

 

[duffy99]

Also while tightening up the contact wheels until there was no play I noticed that one wobbles , I'm not sure if by tightening it I misaligned the bearings( kmg wheels) I used machine washers so to not press onto the outer bearing. I'm getting pretty frustrated at this point. The bearing might be damaged now so I'm thinking of replacing them on the 3" wheel . The bearings will have good movement when I hold both inner rings by hand then after a few rotations seem to lock up that and side to side movement per rotation. I think I have a curse of wrecking things before I even use them.

 

[BossDog]

Some of thi isn't making sense to me here. I will be in the shop Saturday morning and we can talk through it. The number is in the contact us area on the front page.