top

Munchausen's Replica

Post new topic Reply to topic FizzX.org Forum Index | WhipMag Discussion/Development Goto page Previous  1, 2, 3  Next   Page 2 of 3

Tue Jun 17, 2008 1:42 pm PostPost subject:
Yadaraf
Major Contributor
Major Contributor


Joined: 30 Jan 2008
Posts: 436

Reply with quote

EDIT: moved reply to "reports from the front" thread.

.. reply: http://fizzx.com/viewtopic.php?p=5198#5198
_________________
Any sufficiently advanced technology is indistinguishable from magic. (Clarke's law)
Changing the world, one magnet at a time. (Yada)
Back to top
View user's profile Send private message
 
Tue Jun 17, 2008 5:58 pm PostPost subject:
korkskrew
Regular Contributor
Regular Contributor


Joined: 25 Jan 2008
Posts: 106
Location: Longmont, CO

Reply with quote

alsetalokin wrote:
With rotor removed so the stator is free to spin freely, when I give it the thumb-flip technique, it spins for around 5 seconds. This is just an estimate, not an instrumental measurement. But for sure it is waaay longer than 1 second.

Could you guesstimate the speed that you got from the thumb flip?
800 - 1200 RPM?
1200 - 1800 RPM?
More?
Back to top
View user's profile Send private message Send e-mail
 
Tue Jun 17, 2008 6:32 pm PostPost subject:
alsetalokin
Site Admin


Joined: 14 Apr 2007
Posts: 640
Location: Sol III

Reply with quote

I'll try to get a measurement later this evening. Visitors in the lab today so I'm a bit frantic...
_________________
"Abandon hope, all ye who enter here..."
Back to top
View user's profile Send private message
 
Thu Jun 19, 2008 5:08 am PostPost subject:
munchausen
Regular Contributor
Regular Contributor


Joined: 28 Jan 2008
Posts: 54

Reply with quote

I picked up some bearings at the quasi-local hobby shop. They carry boca bearings. I think I picked up 13mm diameter bearings but I'll confirm tomorrow. ($4 each) I also got some Rotor blades . . . for my helicopter.

Still haven't chosen a rotor bearing. I disassembled 3 HDDs. I have 3 pivot head bearings, but I want the 5400 rpm disc bearings. Are they integral to the motor? Any idea on how to get them out?

I also got everything for the stators from Lowe's ($8 ).

Yada, Do you screw your stators into your base? do you just press them in? how do they stay put?

Al, you said not to spend too much $$ on bearings but yours seem very fast. I don't think these will be even close to that smooth. Should I try to get some lighter oil for them? wd40? something with teflon??

hmmmmm Neutral
Back to top
View user's profile Send private message
 
Thu Jun 19, 2008 5:37 am PostPost subject:
Harvey
Major Contributor
Major Contributor


Joined: 16 Jan 2008
Posts: 1927

Reply with quote

Hi Munch, congrats on the parts.

I was disapointed with the performance of the teflon lube I tried. I wash my bearings with WD-40 and then blow them out with air. Seems to work ok, but nowhere near 5 second spins on the stators.

Notice on page 1 this thread the image in Yada's post that shows all the stator hardware. There you will see the screw he uses to fasten it to the base. 4-40 threads IIRC. So the base is drilled and tapped. There may be some photos in Yada Testing thread that show a profile of the mounting as well.

Cheers,
Cool

Edit: Nope, the one I was thinking of was in the 'from the front thread'

Yadaraf Posted This Pic


Last edited by Harvey on Thu Jun 19, 2008 5:43 am; edited 1 time in total
Back to top
View user's profile Send private message
 
Thu Jun 19, 2008 5:41 am PostPost subject:
Yadaraf
Major Contributor
Major Contributor


Joined: 30 Jan 2008
Posts: 436

Reply with quote

munchausen wrote:
Yada, Do you screw your stators into your base? do you just press them in? how do they stay put?

Munch,

Start with your bearing, a small 1/8" long piece of shrink tubing (optional), and a 3/4" 4-40 pan-head screw, or cap head that has been ground down.

1. Place the shrink tubing around the screw threads, just beneath the screw head, shrink it down, and then place the screw in the bearing. (The shrink tube is to help center the screw in the bearing bore. Wink )

2. Place the two nylon washers on top of the bearing, and make sure that the screw head clears the two washers in all directions.

3. Place the R834DIA on top of the two washers, which will cause the assembly to bind together due to the magnetic attraction to the bearing.

Note: Because you are using a 13 mm bearing, the next step will be different for you.

4. Wrap a piece of packing tape around the circumference of the magnet and washers only -- your 13 mm bearing will fit very snug in the 1/2" ID nylon bushing, but the magnet will have some clearance around it.

5. Press the nylon bushing over the entire assembly, from the magnet downward. (Because the 4-40 screw is dangling from the bottom of the bearing, you'll have to find a surface with a hole in it to accommodate the screw while you press on the bushing. You might try a drill case -- remove a few bits and you have a surface with holes in it. Wink )

6. After pressing on the bushing, trim any excess packing tape.

7. Note: At this point, the pan-head 4-40 screw can't be removed without disassembly, because the head can't pass through the bore of the R834DIA. However, if you use a cap screw you can remove the screw like Al.

8. To mount the stator assembly, simply screw the 4-40 into a pre-tapped hole in the base.

Question .. Q: Make sense?

I hope to make a video, but I've been very busy lately.

Cheers Smile
Yada ..
_________________
Any sufficiently advanced technology is indistinguishable from magic. (Clarke's law)
Changing the world, one magnet at a time. (Yada)
Back to top
View user's profile Send private message
 
Thu Jun 19, 2008 2:51 pm PostPost subject:
munchausen
Regular Contributor
Regular Contributor


Joined: 28 Jan 2008
Posts: 54

Reply with quote

Harvey wrote:
Hi Munch, congrats on the parts.

I was disapointed with the performance of the teflon lube I tried. I wash my bearings with WD-40 and then blow them out with air. Seems to work ok, but nowhere near 5 second spins on the stators.

Thanks. So what are your plans to speed up that bearing?

When I spin the head pivot bearings from the HDDs I took apart, I still don't get long spin times.

I'll try to post some pictures of my HDD motors. Maybe you guys can help me get those bearings out.

Yadaraf wrote:
2. Place the two nylon washers on top of the bearing, and make sure that the screw head clears the two washers in all directions.

3. Place the R834DIA on top of the two washers, which will cause the assembly to bind together due to the magnetic attraction to the bearing.

Note: Because you are using a 13 mm bearing, the next step will be different for you.

4. Wrap a piece of packing tape around the circumference of the magnet and washers only -- your 13 mm bearing will fit very snug in the 1/2" ID nylon bushing, but the magnet will have some clearance around it.

8. To mount the stator assembly, simply screw the 4-40 into a pre-tapped hole in the base.

Your directions do make sense but I have a few questions.

1. Are you certain that your nylon washers are only touching the outer race of the bearing, and that your magnet is not touching the pan head screw?

2. Will my 13mm bearing be too tight you think?

3. Do you think I will be able to tap a thread into MDF?? I can always just press it in for now.

4. Do you think your stators are well-balanced?

5. How are we going to get these bearings to spin faster??
Back to top
View user's profile Send private message
 
Thu Jun 19, 2008 4:53 pm PostPost subject:
Yadaraf
Major Contributor
Major Contributor


Joined: 30 Jan 2008
Posts: 436

Reply with quote

munchausen wrote:
Your directions do make sense but I have a few questions.

1. Are you certain that your nylon washers are only touching the outer race of the bearing, and that your magnet is not touching the pan head screw?

2. Will my 13mm bearing be too tight you think?

3. Do you think I will be able to tap a thread into MDF?? I can always just press it in for now.

4. Do you think your stators are well-balanced?

5. How are we going to get these bearings to spin faster??

Munch

1. I'm using the R2AZZ Boca bearings (0.500 OD x 0.125 ID) from Lessons Learned, and the washers clear the inner race with lots of room to spare. I suspect that your 13 mm washers have a larger bore, and the washer might interfere with the inner race, so doube check. Two of the washers when stacked are thicker than the pan head, so I know that the magnet is sitting on the washers and not touching the screw. Cool

2. I tried 13 mm x 6 mm, and they fit great inside the nylon bushing, but the bore was large and I had to use a #10 screw to mount them. Also, even after I removed the grease they were very tight (no radial play or precession angle). They cost $8.

3. You can tap almost anything if you take your time and use cutting oil or possibly WD40. Smile

4. I think my stators are well balanced, because I don't see anything to throw them out of balance. They spin very freely and smoothly.

5. At first my bearings were rather slow -- around 1 second spindown after I finger flipped them. I removed the seals and then degreased them and they spin waaaay faster -- like 4 seconds or so. The shields are held in by a very tiny clip, and are easily removed and replaced, but I didn't replace them.

Hope that helps. You might have problems with the 13 mm bearings if they remain overly tight -- even after degreasing

Lastly, to simulate aging and wear I plan to spin a bearing overnight in solution of silica (polishing compound?) to wear down the balls and races a bit more. Not sure when I'll have time, though.

Cheers Smile
Yada ...
_________________
Any sufficiently advanced technology is indistinguishable from magic. (Clarke's law)
Changing the world, one magnet at a time. (Yada)
Back to top
View user's profile Send private message
 
Thu Jun 19, 2008 5:29 pm PostPost subject:
munchausen
Regular Contributor
Regular Contributor


Joined: 28 Jan 2008
Posts: 54

Reply with quote

Yadaraf wrote:
2. I tried 13 mm x 6 mm, and they fit great inside the nylon bushing, but the bore was large and I had to use a #10 screw to mount them. Also, even after I removed the grease they were very tight (no radial play or precession angle). They cost $8.

Lastly, to simulate aging and wear I plan to spin a bearing overnight in solution of silica (polishing compound?) to wear down the balls and races a bit more. Not sure when I'll have time, though.

I plan to use a washer and the head of the screw to hold on to the bearing. But you are right, the bore is large. I may call back to see if someone else can look through those bearings for the ones you bought. He only quoted metric sizes.

I care more about speed for now than radial play or precession angle (couldn't we tip the bushing to simulate that?).

I left my stone polishing silica spinner in my other pair of pants, but what if I spun the inner race of the bearing with a dremel for a little while? I wouldn't want to put 30,000 rpms in it though--might turn it into a 13.5mm bearing Laughing
Back to top
View user's profile Send private message
 
Thu Jun 19, 2008 5:36 pm PostPost subject:
Mr.Entropy
Regular Contributor
Regular Contributor


Joined: 28 Aug 2007
Posts: 67
Location: Canada

Reply with quote

Yadaraf wrote:
The shields are held in by a very tiny clip, and are easily removed and replaced, but I didn't replace them.

I think I remember from the picures that Al's bearings have steel (i.e., ferromagnetic) shields. Could be significant.
Back to top
View user's profile Send private message
 
Thu Jun 19, 2008 6:00 pm PostPost subject:
Yadaraf
Major Contributor
Major Contributor


Joined: 30 Jan 2008
Posts: 436

Reply with quote

Mr.Entropy wrote:
Yadaraf wrote:
The shields are held in by a very tiny clip, and are easily removed and replaced, but I didn't replace them.

I think I remember from the picures that Al's bearings have steel (i.e., ferromagnetic) shields. Could be significant.

Absolutely correct. Eventually I'll put the shields back on -- for dust, etc.

For the time being I need them off in order to age my bearings "silica slush." Cool

Cheers Smile
Yada ..
_________________
Any sufficiently advanced technology is indistinguishable from magic. (Clarke's law)
Changing the world, one magnet at a time. (Yada)
Back to top
View user's profile Send private message
 
Thu Jun 19, 2008 6:09 pm PostPost subject:
Yadaraf
Major Contributor
Major Contributor


Joined: 30 Jan 2008
Posts: 436

Reply with quote

munchausen wrote:

I plan to use a washer and the head of the screw to hold on to the bearing. But you are right, the bore is large. I may call back to see if someone else can look through those bearings for the ones you bought. He only quoted metric sizes.

I care more about speed for now than radial play or precession angle (couldn't we tip the bushing to simulate that?).

I left my stone polishing silica spinner in my other pair of pants, but what if I spun the inner race of the bearing with a dremel for a little while? I wouldn't want to put 30,000 rpms in it though--might turn it into a 13.5mm bearing Laughing


The 13 mm bearings that I bought were from a local hobby shop, and metric was all that they stocked. I drove around to three hobby shops and couldn't find anything better, so eventually bought online from Boca.

As for the inner race, I doubt isolating it will do any good. I think the balls and the races need to seat together -- like breaking in an engine.

Al's "magical" bearings might work, because they are old, worn, and broken in. I think radial play might be a key, because this gets worse as bearings wear. I need to post my precession angle test (*argh*), which IMHO is a good indicator of radial play, and thus, possibly an indicator of wear or quality in general.

Cheers Smile
Yada ...
_________________
Any sufficiently advanced technology is indistinguishable from magic. (Clarke's law)
Changing the world, one magnet at a time. (Yada)
Back to top
View user's profile Send private message
 
Thu Jun 19, 2008 6:42 pm PostPost subject:
munchausen
Regular Contributor
Regular Contributor


Joined: 28 Jan 2008
Posts: 54

Reply with quote

Yadaraf wrote:
As for the inner race, I doubt isolating it will do any good. I think the balls and the races need to seat together -- like breaking in an engine.

Ummm, I wasn't planning on taking apart the bearing. I was going to clamp down the outer race, and spin the inner race very, very fast.

So instead of using the bearing at a couple hundred rpms for 3 months, I would spin it at 20,000 rpms for 3 hours. Idea Just a thought.
Back to top
View user's profile Send private message
 
Thu Jun 19, 2008 6:56 pm PostPost subject:
Yadaraf
Major Contributor
Major Contributor


Joined: 30 Jan 2008
Posts: 436

Reply with quote

munchausen wrote:
Yadaraf wrote:
As for the inner race, I doubt isolating it will do any good. I think the balls and the races need to seat together -- like breaking in an engine.

Ummm, I wasn't planning on taking apart the bearing. I was going to clamp down the outer race, and spin the inner race very, very fast.

So instead of using the bearing at a couple hundred rpms for 3 months, I would spin it at 20,000 rpms for 3 hours. Idea Just a thought.



LOL ... I had a vision of you grinding away at just the inner race. Funny.

The shields on my 13 mm were tricky to remove, and I ended up destroying them in the process. Try using a sewing needle to pry them off. You might have to indent them first.

If you're going to spin the bearing, try submersing it in some polishing compound at the same time -- something to help wear down the surface faster.

Cheers Smile
Yada ...
_________________
Any sufficiently advanced technology is indistinguishable from magic. (Clarke's law)
Changing the world, one magnet at a time. (Yada)
Back to top
View user's profile Send private message
 
Thu Jun 19, 2008 9:26 pm PostPost subject:
Yadaraf
Major Contributor
Major Contributor


Joined: 30 Jan 2008
Posts: 436

Reply with quote

munch,

If you use packing tape, then be careful not to lubricate the bearing afterwards, because this will remove the gum from the packing tape, and guess where the gum residue goes ... sticky bearings.

Cheers Smile
Yada ...
_________________
Any sufficiently advanced technology is indistinguishable from magic. (Clarke's law)
Changing the world, one magnet at a time. (Yada)
Back to top
View user's profile Send private message
 
Thu Jun 19, 2008 10:23 pm PostPost subject:
overconfident
Major Contributor
Major Contributor


Joined: 10 Feb 2007
Posts: 1121

Reply with quote

Yadaraf wrote:
If you use packing tape, then be careful not to lubricate the bearing afterwards, because this will remove the gum from the packing tape, and guess where the gum residue goes ... sticky bearings.


Voice of experience?
Back to top
View user's profile Send private message
 
Thu Jun 19, 2008 11:52 pm PostPost subject:
Yadaraf
Major Contributor
Major Contributor


Joined: 30 Jan 2008
Posts: 436

Reply with quote

overconfident wrote:
Yadaraf wrote:
If you use packing tape, then be careful not to lubricate the bearing afterwards, because this will remove the gum from the packing tape, and guess where the gum residue goes ... sticky bearings.


Voice of experience?


Busted ...



I autopsied a bearing to remove the shield and degrease the bearing, when I discovered that the whole assembly -- including nylon washers -- was very very sticky. It was a good lesson, not to mention that degreasing the Boca bearing increased the spindown dramatically -- like 4x. I'm now using dry bearings, and don't even plan to use WD40.

There's no load on these bearings, so they might run dry without issue -- especially if I "season" them first in polishing compound to improve the surfaces.

EDIT. Because the device isn't working, anyway, I expect the bearings to run dry for a very very very long time. Laughing

Cheers Smile
Yada ..
_________________
Any sufficiently advanced technology is indistinguishable from magic. (Clarke's law)
Changing the world, one magnet at a time. (Yada)
Back to top
View user's profile Send private message
 
Fri Jun 20, 2008 3:28 am PostPost subject:
Harvey
Major Contributor
Major Contributor


Joined: 16 Jan 2008
Posts: 1927

Reply with quote

When I used an air nozzle to spin up my bearings I discovered it is quite easy to dry them out and spin them at ultrasonic speeds in one swell fweep. Thats the sound they make, fweep, fweep, fweep. The harmonics generated actually stop the bearing completely in between spin ups with continuous airflow.

Interestingly, each bearing has its own fweep signature. Perhaps there is some way to record those fweeps for analysis. Mr. Green

I got a couple new toyls today - will post results in Yada Testing thread later.

Cool
Back to top
View user's profile Send private message
 
Fri Jun 20, 2008 5:03 am PostPost subject:
Yadaraf
Major Contributor
Major Contributor


Joined: 30 Jan 2008
Posts: 436

Reply with quote

Harvey wrote:
When I used an air nozzle to spin up my bearings I discovered it is quite easy to dry them out and spin them at ultrasonic speeds in one swell fweep. Thats the sound they make, fweep, fweep, fweep. The harmonics generated actually stop the bearing completely in between spin ups with continuous airflow.

Interestingly, each bearing has its own fweep signature. Perhaps there is some way to record those fweeps for analysis. Mr. Green

I got a couple new toyls today - will post results in Yada Testing thread later.

Cool


Harvey,

I believe that Munch is in the market for some stator bearings. He knows that I got mine from Boca.

.. Q: Where did you get yours? Part #?

Cheers Smile
Yada ..
_________________
Any sufficiently advanced technology is indistinguishable from magic. (Clarke's law)
Changing the world, one magnet at a time. (Yada)
Back to top
View user's profile Send private message
 
Fri Jun 20, 2008 8:36 am PostPost subject:
Harvey
Major Contributor
Major Contributor


Joined: 16 Jan 2008
Posts: 1927

Reply with quote

Quote:

.. Q: Where did you get yours? Part #?


WJB Bearings. Their headquarters are within driving distance and I was able to get a catalog while I was there. The part is an industry number R2A. This does not come in the Wi extended inner race nor flange R-EE or FR-EE. I would have preferred the R-EE if it was available in the R2A OD and Bore:(

The also carry metric sizes, but none with a 3.5mm Bore. I used the R4A in my rotor because I had a nice new 3/4" bit that fit my 1/2" drill motor. My 1/2 bit was worn and I wanted a relatively true hole. I also intended to create 3/4"->1/2" eccentrics later to adjust runout but it really didn't seem to matter much in the observed actions. My rotor is functional but far from worthy. Rolling Eyes

Cheers
Cool
Back to top
View user's profile Send private message
 
Fri Jun 20, 2008 4:30 pm PostPost subject:
Yadaraf
Major Contributor
Major Contributor


Joined: 30 Jan 2008
Posts: 436

Reply with quote

Harvey wrote:
Quote:

.. Q: Where did you get yours? Part #?


WJB Bearings. Their headquarters are within driving distance and I was able to get a catalog while I was there. The part is an industry number R2A. This does not come in the Wi extended inner race nor flange R-EE or FR-EE. I would have preferred the R-EE if it was available in the R2A OD and Bore:(

The also carry metric sizes, but none with a 3.5mm Bore. I used the R4A in my rotor because I had a nice new 3/4" bit that fit my 1/2" drill motor. My 1/2 bit was worn and I wanted a relatively true hole. I also intended to create 3/4"->1/2" eccentrics later to adjust runout but it really didn't seem to matter much in the observed actions. My rotor is functional but far from worthy. Rolling Eyes

Cheers
Cool


Harvey,

Thanks. Interesting that they don't have online prices and sales. It appear that they only do business via email, catalog, and counter sales.

Cheers:)
Yada ...
_________________
Any sufficiently advanced technology is indistinguishable from magic. (Clarke's law)
Changing the world, one magnet at a time. (Yada)
Back to top
View user's profile Send private message
 
Tue Jul 22, 2008 2:26 pm PostPost subject:
munchausen
Regular Contributor
Regular Contributor


Joined: 28 Jan 2008
Posts: 54

Reply with quote

It's been a while since I've posted an update. So here is what is happening:

I've made stator assemblies, just 3 for now, bearing limited, but I can get boca bearings from the quasi-local hobby shop. I haven't opened, cleaned, or dried any of the bearings. I'm still disappointed in their performance.

The 13mm bearings fit (very) snug inside the nylon bushings. They are probable stretching the nylon too much for perfectionist replicators. The magnets have plenty of room, but my nylon washers are useless. There isn't enough room between the outer race of the bearing (inside the bushing) and the metal washer underneath the pan head screw. I need a very tiny .5" OD, .46" ID gasket, something to just rest on the bearing outer race. I'll look around Lowe's but I doubt they have anything that tiny.

Fo the time being, I've put some tape around the magnets to add to their diameter, so they will fit snug in the bushing, without sticking to the bearing.

Also, I haven't used any shrink tubing so the screws are not in the exact center of the bearings. The stators are still somewhat balanced, but they will not be perpedicular to the base. They spin on a slight axis. This doesn't bother me for now, as I will be able to slightly increase or decrease their distance from the rotor simply by turning the pan head screw once mounted in the base.

There is a lot of 'eccentricity' (read: lack of precision) in the stator assemblies.

Also, I picked up these bearings for the rotor:

http://www.amazon.com/Bones-Reds-Precision-Skate-Bearings/dp/B000FDRQ1S/ref=sr_1_1?ie=UTF8&s=sporting-goods&qid=1216735306&sr=1-1

Since I don't have access to a lathe, I think I'll be making my rotors with a drill press. I plan on cutting out some 6" to 8" squares, drilling a hole for a bearing, pressing in the bearing, then spinning the MDF into a drill bit to cut the proper diameter. Then, I plan to cut a circular channel in the top of the rotor, maybe .25" from the outer diameter. That way I can vary the distance between the rotor mags. I plan to cut a bunch of rotors of different sizes since I have a lot of this MDF.

Any thoughts?
Back to top
View user's profile Send private message
 
Tue Jul 22, 2008 2:49 pm PostPost subject:
Mr.Entropy
Regular Contributor
Regular Contributor


Joined: 28 Aug 2007
Posts: 67
Location: Canada

Reply with quote

munchausen wrote:
Since I don't have access to a lathe, I think I'll be making my rotors with a drill press. I plan on cutting out some 6" to 8" squares, drilling a hole for a bearing, pressing in the bearing, then spinning the MDF into a drill bit to cut the proper diameter. Then, I plan to cut a circular channel in the top of the rotor, maybe .25" from the outer diameter. That way I can vary the distance between the rotor mags. I plan to cut a bunch of rotors of different sizes since I have a lot of this MDF.
Drill bits don't cut sideways. You should use an end mill. One with a 3/8 or smaller shank will fit in your drill press chuck:

http://busybeetools.ca/cgi-bin/product10?&NMCLASS=00144&NSBCLASS=00227&NETID=1045130722081964806

It will pull up on the rotor while you're cutting, so be sure to have some kind of jig in your drill press vice to hold the edge steady.

ETA: Applying a lot of sideways pressure is not good for your drill press. You can do it, since it's only MDF, but be gentle.
Back to top
View user's profile Send private message
 
Wed Jul 23, 2008 1:47 am PostPost subject:
Harvey
Major Contributor
Major Contributor


Joined: 16 Jan 2008
Posts: 1927

Reply with quote

Munch wrote:

I need a very tiny .5" OD, .46" ID gasket, something to just rest on the bearing outer race. I'll look around Lowe's but I doubt they have anything that tiny.


I did this on one of my stators: I took a business card and folded it twice to produce 4 layers. Then, using a 3 hole punch I punched a single hole through all four layers. I then took the stator housing and centered it over the hole visually and penned a circle inside. Then using sissors I cut out the circle leaving the line on. This made perfect litttle paper washers Very Happy

Cheers,

Cool

ETA: Also, consider not using a washer under the screw. And, as Yadaraf suggests, try a small bit of heat shrink tubing around the screw to help keep it well centered. Wink
Back to top
View user's profile Send private message
 
Wed Jul 23, 2008 1:58 am PostPost subject:
Harvey
Major Contributor
Major Contributor


Joined: 16 Jan 2008
Posts: 1927

Reply with quote

Munch wrote:

Since I don't have access to a lathe, I think I'll be making my rotors with a drill press. I plan on cutting out some 6" to 8" squares, drilling a hole for a bearing, pressing in the bearing, then spinning the MDF into a drill bit to cut the proper diameter.


I did something similar for my HDPE layers. I used a finishing nail for the center pivot (tight fit after drilling undersize). I then secured a 1/8" drill guide into piece of 2x6 wood so that its edge was exactly 72mm from the center hole. Using a power drill I oscillated the bit up and down in the guide and rotated the work through the cut. It was slow, but very effective.

I agree, that if you have a drill press, you should use a side cutting mill. The only problem is spindle walk. Without a drill guide, any lateral play in the spindle will result in variations in the rotor.

Let us know how it goes.

Here is a picture of the Jig I used (you can click on it for higher res):
http://urad.net/forums/gallery/displayimage.php?album=1&pos=47
You can see the drill guide just up and to the right of the knot. And the finishing nail is there next to the drill bit and chuck-key.

Cheers,

Cool
Back to top
View user's profile Send private message
 
Sat Jul 26, 2008 12:48 am PostPost subject:
alsetalokin
Site Admin


Joined: 14 Apr 2007
Posts: 640
Location: Sol III

Reply with quote

It is easy to true up disks (within a certain tolerance of course) by using a jig and a disc sander. This is how I true the large discs in my Bonetti machines.
Just drill a center hole in the rough workpiece and use a tight-fitting temporary axle, that can be mounted an adjustable distance from the sander's disc. Mount the rough blank on the axle, turn on the sander, and move the adjustment so the farthest-out edge of the workpiece contacts the sanding disc lightly, and rotate the work. Readjust and repeat as needed until the entire periphery of the workpiece is trued by the sander.

If you chuck a mill into a drill press chuck you will eventually damage the chuck (the mill is a lot harder than the chuck jaws).
_________________
"Abandon hope, all ye who enter here..."
Back to top
View user's profile Send private message
 
Sat Jul 26, 2008 9:16 am PostPost subject:
Harvey
Major Contributor
Major Contributor


Joined: 16 Jan 2008
Posts: 1927

Reply with quote

Yeppers, my rotor was a bit more 'vibratory' until I spun it up with air to about 3K and then took a barrel sander in my dremel to it's periphery. Rounded off all them thar bumps I did Wink , but the valleys remain Sad.

Good to see 'ya online Al. How's things on the TDY front?

What'd you think of my drawing over there in the Mondrasek thread? Let me know if you want to know what I left out Wink

Cheers,
Cool
Back to top
View user's profile Send private message
 
Thu May 21, 2009 5:44 pm PostPost subject:
munchausen
Regular Contributor
Regular Contributor


Joined: 28 Jan 2008
Posts: 54

Reply with quote

You probably thought my replica would never make it. Well I'm back to prove you (and my wife) wrong.

I think I finally secured the rest of the tools I will need to fabricate this replica. It only took 10 months.

The weekend is looking busy but I am hoping to have some time to tinker on Monday. I will post a bunch of pics to the whipmag photobucket folder.

I also plan to upload video. Does anyone want to make a whipmag youtube account?

More later.
Back to top
View user's profile Send private message
 
Thu May 21, 2009 6:01 pm PostPost subject:
overconfident
Major Contributor
Major Contributor


Joined: 10 Feb 2007
Posts: 1121

Reply with quote

munchausen wrote:

I will post a bunch of pics to the whipmag photobucket folder.


I guess you have the password for the whipmag photobucket account? If not, PM me.

munchausen wrote:

I also plan to upload video. Does anyone want to make a whipmag youtube account?


I have been using the "whipmag" Youtube account for quite some time now. There's not many videos, but I have posted a ton of comments using that name. Wouldn't want you to be held responsible for anything I might have said.
Back to top
View user's profile Send private message
 
Wed Jun 03, 2009 5:21 pm PostPost subject:
munchausen
Regular Contributor
Regular Contributor


Joined: 28 Jan 2008
Posts: 54

Reply with quote

I do have the password. I may pass on the video account for now, but once I begin testing, maybe someone can start a public account.

I thought I had everything thing I needed to make the replica at the time but now I know I do. I now have the drill bit I need and I picked up a table saw.

The disk for my first replica is almost complete. I spun it around the bearing and into the sanding disk which gave me a nice smooth even edge. Unfortunately, I found out how much play was in my skateboard bearing. I currently press the bearing into the rotor but I my hole goes completely through the rotor. Not great but I think it will do for now.

The next step is to make some room for the rotor bearings. I will do this drilling straight down into the rotor for this first replica. I plan to use the table saw to make channels in the next project, before I cut a circle out.

I have taken some pics but the lighting isn't great. I'll try to post some later.

I've also discovered some problems with the layers of fiber in this MDF. I will be interested to see how fast I can spin this thing and keep it together.

More later.
Back to top
View user's profile Send private message
 
Post new topic Reply to topic FizzX.org Forum Index | WhipMag Discussion/Development
View previous topic
View next topic
Display posts from previous:   




You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum