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The top-secret project..... #6: The Wheels On The TSP.......

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Blog entry by MSlumberjocks posted 01-26-2012 01:17 AM 5584 reads 1 time favorited 100 comments Add to Favorites Watch
« Part 5: The Assembly Line Part 6 of The top-secret project..... series Part 7: The Race To The Finish Line »

The wheels on the top secret project go round and round, round an…....

Ok, I’ll stop that since the one I’ve worked on so far isn’t going around too well.
I (William) am making a seperate post on the wheels since it has been my biggest fiasco of this project thus far. We (KTMM and I) changed the design of the wheels from the plan to use the material we had. I had this grand idea on how to true the circumference up balance it on my lathe. This post will start with the nightmare that has turned into for me.

This is the wheel that KTMM so carefully cut out and I glued up back towards the beginning of this project. Laid on it is one of the bearings. What I’m trying to do is to make a piece on my lathe that hold this wheel, with the bearings inserted, so it can be tuned on the lathe.

Here is my faceplate for the inboard side of my lathe. It is sitting on the piece of wood I originally started with this morning. Notice anything? I’m no expert woodturner, but even I should have caught this mistake. I was told once that it’s never ok to turn small wood like this unless the grain is running parallel to the lathe. I figured that since I was only making a sort of jig though, that it would be ok.
I figured out otherwise when I hit a small knot, but a bigger void, and this piece of wood blew apart. I was going to shoe the pieces, but since I had it balanced well and it was turning at about 3500 RPMs, I didn’t find much of it.
So after I went to check my britches, back to the drawing board.

I think because I was a little shaken up, I took no photo for a little while.
Here though, I screwed a new piece of wood to the faceplate and started over. I worked it down till the splindle was just a hair larger than the inside race of the bearing. Then I slowly worked it down from there with emory cloth until I had it so the bearing would just slide all the way up to the larger part.

I snapped a photo of the wheel mounted on here, but it didn’t turn out.
I installed the bearings on each side of the wheel. Then I slipped the wheel with the bearing onto the spindle. I put in screws from the back side through the larger part of my spindle piece, into the wheel to hold it on. Then I took a large dowel rod and drilled a one inch hole into one end of a small section for a cap on the ouside to keep the outer bearing from moving.

Now let me back up.

Before all this, I had to drill holes for the bearings into the wheels.
Because we done them different than the plans, the wheels are too large to do on my drill press like I’d hoped. So, I set out with my handheld drill trying to drill the holes as straight as I possibly could. That didn’t work out so well.

Side one.
As I tried to start the hole, the forstner bit walked all over the place. I caught it before it got too deep though to figure out why.
The quarter inch hole in the center we used for the router circle cutter, and to line up the pieces for glueup, was just large enough that it was allowing the center point of the bit to go crazy.
I inserted a piece of dowel into the hole, trimmed it flush, and this gave something for the center point to bite into and the hole drilled fine.
It doesn’t look like it in the photo, but this bearing actually is pretty tight in the hole. It’s just the very beginning of the hole that is messed up.
I figured this would work. It was too late to do much about it anyway. So, onward I pushed.

Side two.
I made sure to insert and trim a piece of dowel flush and this side drilled beautifully.
Now, after getting the bearings to sit flush on each side, I wanted to drill the center of the wheel out at a smaller diameter so the bearings would stay flush with the outside of the wheel.

The bit went through the first layer fine. Then it hit the middle layer and it was like trying to tame an angry bull. I think it was trying to follow the grain or something, but I’ve never had a bit try to do this in plywood. Anyway, the hole, from the middle piece on, went at an awkward angle.
When done, the bearings sit the way they should though, so I hoped I would be fine here.
On to the lathe.

I am coming into a couple of issues here.
At first, the way the wheel acts once it’s up to speed, I figured the hole isn’t perfectly center. I’m still not sure this isn’t exactly a fact.
However, I then noticed the entire lathe was vibrating worse than it normally does. So maybe the lathe is the problem.
Anyway, this isn’t working out. I see it could be one or more of several problems:
1. center hole not centered correctly. If this is the case, maybe if I added more speed and used a sanding block carefully.
2. too much weight. Without the wheel already pretty true to begin with, maybe it’s just too much weight to do on my lighteweight lathe.
3. it’s possible that my drilling problems in the beginning is now causing an out of balance problem.

So here is where I’m at.
I removed the wheel from the piece I made to recheck everything. It now has more out of balance motion than it did before I put the wheel on it. I’m wondering if the weight of the wheel put enough force on the spindle part of this piece to actually make the wood “bend”?
At this point, it’s back to the drawing board.
I think the wheel might can still be saved. I’ll wait for a second opinion on that from KTMM. I wasn’t supposed to be doing this anyway. I agreed last time he was here to let KTMM handle the wheels.

I haven’t given up, but at the moment I’m waiting on re-enforements.

KRUNK, YOU’RE UP!

.

EDIT 1/30

So, I explained that KTMMhad an idea to make the wheels work. Now that I know it worked, I’m back to show you what we done.

The problem has been the wheels are too large to go on the drill press, the holes aren’t perpendicular to each other, and it appears a little bit maybe just shop gremlins giving us a headache. KTMM told me he had a fool proof plan though, so here it is.

The wheels are too thick as we’ve built them to put flanges on each side like the plans call for. However, we can put the bearing straight into one side like we wanted, and add a flange to the other side in order to give us the adjustablility to get the wobble out of the wheels. In order to do so though,the flange has to be inset into the side of the wheel. So, using the circle jig I made, I spent a better part of today hogging out material.
First though, just in case, I started with my latest recut wheel. That way, if this didn’t work, I wouldn’t be messing up too much material. We are starting to run low on the oak ply by the way.

Now remember, I’d already messed this wheel up. The larger hole for the bearings were already cut, wrongly, but cut. So I had to use masking tape and line this wheel up with one of the other wheels to give me my center quarter inch pivot point.
Then, using my circle jig, I started on the outside of where I wanted to hog out the material. I set my router to only take one layer of plywood off. After making the first pass with a half inch bit, I just moved over four holes in my jig and made another pass. I kept doing this until I had hogged out enough material to insert a bearing inset into a flange.

Because taping this wheel to another wasn’t actually as stable as I’d have liked, this process left a pretty rough bottom to the hogged out area. That’s alright. KTMM sharpened up my latest find the other day, some Stanley No.40 chisels. He done a heck of a job, because they made short work of smoothing this up.


Here is the cleaned up wheel and the flange with the bearing in it. The circle jig allowed me to get the holes just right so that the bearings have to be drove in with a piece of wood and a hammer. This is how we wanted them.

I drilled holes in the wheel so that I could get clamps on the flange and hold everything to get it lined up.
The shaft has been cleaned up with emory cloth and is clamped up in a Shop Mate.

After trying several clamps that I had, the only ones that would fit through the holes were so long that they were too cumbersome. I wound up using the shortest clamps in the shop, which belong to KTMM. I couldn’t get the pins out of the end to remove the head so they’d go through the hole. So in the end, they got grinded off. I hope KTMM doesn’t get too upset. If he does, I’ll have to replace his clamps.

I tried several methods of getting the wobble out of the wheel. None worked with the wheel spinning like I’ve seen other people do. I just couldn’t get it. So I wound up using my dial guage and slowly working the wheel around to find the area that needed adjusting.
Also in this photo, you may notice the shaft is now in the lower wheel block, which is then clamped to the Shop Mate. I found out the Shop Mate alone wouldn’t hold the shaft well enough.
I also learned that after a lot of work cleaning up the shaft, if you let it fall out of the Shop Mate and hit concrete, it will take time to clean it up again where the corner of the end hit hard on said concrete.

After getting the wheel to where there was less than ten thousands of an inch of runout on the outer edge (don’t think I’ll get any better than that on a wooden wheel) I screwed the flange to the wheel. I then removed the wheel from the shaft, took the flange off, used the screw holes as reference points, and glued the flange back on in addition to the screws.

And we FINALLY have a wheel that is ready for truing, with so little wobble that it is not noticeable.

See?
This photo was taken with the wheel spinning as fast as I could get it going by hand.



100 comments so far

View Dave's profile

Dave

11205 posts in 1590 days


#1 posted 01-26-2012 05:49 AM

William I would look at your router table for the truing the wheel. Use your plunge router for the bearing holes. IMHO
How many lessons did you learn today?
Great effort in your attempts.

-- Superdav "No matter where you go - there you are." http://chiselandforge.com

View KTMM (Krunkthemadman)'s profile

KTMM (Krunkthemadman)

973 posts in 1944 days


#2 posted 01-26-2012 07:07 AM

Yuuuuup, guess im up. I have a couple of ideas, but ill save them for the visit…...
Until then.

-- Practice does not make perfect. Only perfect practice makes perfect. Vince Lombardi

View spamfilterman's profile

spamfilterman

147 posts in 1772 days


#3 posted 01-26-2012 03:46 PM

Interesting. I just bought the plans for this project too… just collecting parts right now. I think it will take me a couple years before I actually finish.

View Sylvain's profile

Sylvain

590 posts in 1250 days


#4 posted 01-26-2012 04:52 PM

There is much more chance to have your bearing holes perpendicular to the wheel (no wobble) with a plunge router as suggested by superdav721. (at least as far as the plunger columns are perpendicular to the sole/base plate)

Have a look at this French web site

http://www.lescopeaux.asso.fr/Techniques/Docs/Sante_Tripode_Anglais.pdf

This is a clever circle jig for router; it does not use a central pin (no mark).
The other advantage is that you can cut a circle whose minimum diameter is the bit diameter (well than you don’t need the jig, but if you want let’s say 1.05 X the bit diameter you can do it).

They have other interesting material but usually in French.

With a central pin you can not go through the board without loosing your reference. So you need a bearing bit to finish the hole using the start of your circle as a guide for the last part.

As You don’t need to cut a lot of holes for this project, if your forstner bit has the ad-hoc diameter, I would just cut a router template in a piece of MDF small enough to be able to make it with the drill press and use it to guide a router on the wheel.

If your forstner bit would not have the ad-hoc diameter, with the jig hereabove you could finely adjust the hole diameter to achieve the desired thightness for the bearing.

-- Sylvain, Brussels, Belgium, Europe - The more I learn, the more there is to learn

View William's profile

William

9287 posts in 1593 days


#5 posted 01-27-2012 06:25 AM

Thank you all.
These are some very interesting thoughts. I don’t think they’re going to be put to use on this particular project, but are some thought to ponder for the future.

spamfilterman,
I truly believe if you plan on using the original idea that’s in the plans for the wheels, you will have no problems at all. Ours is a little more troublesome because we are changing a few things here and there.
As far as the wheels go, we are building ours out of some heavy oak ply that KTMM had. They are heavier, and the finished wheel will be thicker than what’s in the plans.
We are also moving our bearings inboard instead of using flanges because of the added width. This can be worked out, but worst case scenerio, we can always fall back and go ger some plywood to build them as the plans dictate.

All that being said, if we don’t screw up all of them, before we get to the worst case scenerio, we can cut more wheels and try again (we still have some more oak ply).
So stay tuned.
Once I get KTMM over here and we put both our heads together, along with some ideas we’ve already been discussing via text and telephone calls, we’ll just see where this journey leads us.

Again, thanks for the ideas.
As I’ve said several times, I only recently got a good router. I had one before, but it was a POS. I used to shy away from circles. Now that I got a good router though, I’m looking at better ways to cut them using a router. So I will definately be taking some of these idea forward into the future.
Since KTMM wasn’t able to come this evening as planned, I spent the later part of the evening building a new jig for larger circles. I’ll be posting it in my blog section soon.

EDIT

I posted a blog on the new circle cutting jig here.

-- http://wddsrfinewoodworks.blogspot.com/

View William's profile

William

9287 posts in 1593 days


#6 posted 01-27-2012 06:32 AM

Oh, by the way,
The idea that started this post turned out to be a complete wash.
After sleeping on it, I went into the shop and took the wheel off of the “jig” I’d made this morning.
As it turns out, my originally straight spindle that everything was riding on is no longer true itself. Either the wood drying or the weight of the wheel had thrown everything I worked on most of yesterday out of whack. Because of this, it’s impossible to tell for a fact how much of the “out of true” problem is in the wheel and how much is in the “jig” I had it mounted one.

Since I didn’t get to show it yesterday though, here’s photos of the wheel mounted up on the, now failure, of a jig.


-- http://wddsrfinewoodworks.blogspot.com/

View devann's profile

devann

1735 posts in 1443 days


#7 posted 01-27-2012 07:36 AM

William, why did you go and say what you’re building is a secert? Now we all gotta know what that thing is going to be. I’ll check back later. ;^)

-- Darrell, making more sawdust than I know what to do with

View William's profile

William

9287 posts in 1593 days


#8 posted 01-27-2012 02:54 PM

Devann,
It’s only a secret at this point to the ones who haven’t figured it out. For those few, we’re keeping it a secret.
I’m sure though that if you go back and look at tho photo of all six installments in this series, you can easily figure it out.

SuperD said: How many lessons did you learn today?
The “lesson” I learned on that day was not actually, learned, but realized. Some thing we don’t think about until it’s already in progress.
No matter what you do, basic principles still apply.
You know that thing we always talk about router bits and the fact that you have to slow down bigger bits because of the faster speed of the outside diameter?
You mount a wheel that is just a little proud of sixteen inches on a lathe. The center is turning at it’s slowest speed, which on my lathe just happens to be 575 RPMs. I don’t know the formula for figuring out exactly how fast that outer edge is spinning, but I know it is freakishly fast when you’re standing in front of it trying to take material off of it.
At one point, when this fact actually dawned on me, I shut down the lathe and started rethinking my stategy. It took close to a minute for the thing to actually come to a complete stop.

-- http://wddsrfinewoodworks.blogspot.com/

View Sylvain's profile

Sylvain

590 posts in 1250 days


#9 posted 01-27-2012 06:41 PM

length of the circonference : 2 X Pi X R = Pi X D = L

tangential speed L X RPM = speed in Ft/min if your diameter is measured in feet

or (L X RPM ) / 60 = speed in Ft/s

for a 2 ft diameter, the speed would be about 60.2 Ft/s or 3613 Ft/min

If you rpm is too high the part could burst because :
centrifugal acceleration : (2 X pi X RPM / 60)² X R
it increses with the square of the rotational speed.

to be compared with earth gravitational acceleration which is about 32.18 Ft/s²

Let’s say your disc is 2 Ft in diameter (R=1)

then the acceleration is 1105.11 m/s² (sorry I am metric) which is about 3625.7 Ft/s²
about 110 X the gravitational acceleration

consider a chunk of your circle at the periphery with a mass of 0.0456 kg which is about 0.1 pound

then the centrifugal force exercised on this chunk is 1105;11 X 0.0456 = 50.4 N about 11.26 Lbf

Don’t make retrospective nightmares …

-- Sylvain, Brussels, Belgium, Europe - The more I learn, the more there is to learn

View William's profile

William

9287 posts in 1593 days


#10 posted 01-28-2012 12:13 AM

Sylvain,
1: Thank you. I could never have figured all that out.
2: An easier way of saying all that in words I can understand is:
16” diameter wheels.+
Made of heavy oak ply.+
Turning at 575 RPMs at the center.+
Being off balance to begin with+
Mounted on a 1” pine spindle that I turned=

SCARY AS $#!+

-- http://wddsrfinewoodworks.blogspot.com/

View Paul David Soto's profile

Paul David Soto

141 posts in 1357 days


#11 posted 01-29-2012 03:42 PM

Congrats to Superdav for bringing home a Stumpy! Go…MSLumberjocks! LOL!

-- - As a woodworker, it could be interesting sometimes waking up in the morning and asking, "Lord, what will you have me do today?" -Noah

View Dave's profile

Dave

11205 posts in 1590 days


#12 posted 01-29-2012 03:48 PM

Wooo woooo. I won a book. I dont know what book. Wait I cant read. Crap! Hope it has pictures.

-- Superdav "No matter where you go - there you are." http://chiselandforge.com

View William's profile

William

9287 posts in 1593 days


#13 posted 01-29-2012 05:57 PM

It doesn’t have pictures D.
Just send it on over to me.
I’ll read it and tell you what it says.
Congratulations buddy.

-- http://wddsrfinewoodworks.blogspot.com/

View William's profile

William

9287 posts in 1593 days


#14 posted 01-30-2012 04:06 AM

Ok guys, here’s the scoop on the wheels.

I found the drill guide I mentioned. It worked to drill great holes in the form of a drill press, without a drill press, but we still had issues. After setting everything up perfectly, or so I thought, there was so much wobble that I immediately knew that this idea was a failure.
That’s fine though. I had been wanting that guide anyway for my scroll work. I sometimes do portraits where I need to drill holes perfectly for entry holes. There are times, when I do very large portraits, that I can’t get to the entry holes in the middle with the drill press.
So I already had a use for the tool anyway.

Then I started thinking of different ideas. The ideas presented here about doing the holes with the router stuck with me. So I set out with an idea of how I wanted to build a circle jig for small holes. You can see it on a seperate blog here.
This idea was great. My new jog does cut perfect holes. I know this because after testing several on scrap wood, I can cut holes, small ones, with my router now that, using calipers and a dial indicator, are true and square to within LESS than 1/1000th of an inch. In other words, if there’s any imperfections in it, I can’t see it with the best measureing equipment I own.

I cut a test piece out of some scrap in a circle. I cut out holes for the bearings and it was PERFECT. There was no wobble at all. So I moved on to one of our wheels. Keep in mind, I had spent all day working on the jig, testing the jig, and getting everything JUST right. So I cut the holes in one of the wheels. Then I mounted the wheel onto the bearings and shaft and guess what? It wobbles it’s @$$ off. The bearings are not perfectly straight with each other. They are now about a thousands of an inch out of plane with each other. This tiny bit though multiplies from the center outwards. The middle is close, but the outside edges are where the wobble is.

I figured out in short order what the issue is though. The reason my test pieces were perfect and the actual wheels aren’t is the same reason we had to come up with this to start with, the size of the wheels. The test piece had it’s center guide hole drilled out on the drill press, making it perfectly straight. The guide holes on the wheels though weren’t. They were drilled by hand for the same reason we can’t drill the bearing holes on the drill press, the size of the wheels.

So after taking a walk in frustration (don’t have much more hair to be pulling out), some words that were so bad that I had to get away from the kids to say them, it was time to call down and call KTMM and let him know where we stood. It looked to me that the only solution was going to be to scrap our ideas and go with the wheel design within the plans. This is something that KTMM and I did NOT want.

Luckily, before I could even place the call, KTMM had thought of a brilliant idea. It’s one of those ideas that is so obvious that I should have thought of it. I think his latest work of genius will work.

So, tommorrow, I have to go to the doctor. I already know they are going to do an MRI and a few more test on me. So I may be a little worse for wear over the next few days.
As soon as possible though, I will be back in the shop to work on KTMM’s idea. I will tell ya’ll more about this idea after I see if it’ll be a success (which I’m sure it will) or failure.

I would tell you all now, but we are working on a top secret project after all.

-- http://wddsrfinewoodworks.blogspot.com/

View Dave's profile

Dave

11205 posts in 1590 days


#15 posted 01-30-2012 04:29 AM

Not fair you left me hanging on the edge of a wheel. You guys will get it. Just keep whittling at it. Good things and ideas come to those who wait.
Don’t let those doctors poke at you to much.

-- Superdav "No matter where you go - there you are." http://chiselandforge.com

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