Author Topic: The Artful Bodger tries to make something! (Read 31430 times)

John Hill · « **on:** March 07, 2009, 02:32:43 AM »

This is the rotor for my gyroscope, 520grams, 108mm diameter.

It is actually seven pieces of steel, one disc and two rims all cut from rusty 5mm plate. (four steel rivets of course).

I have also made two of the gimbal rings now I need to sort out some problems with the hub and pivot designs!

rleete · « **Reply #1 on:** March 07, 2009, 08:29:21 AM »

No fair just showing the finished product. We need step by step process pics!

John Hill · « **Reply #2 on:** March 08, 2009, 12:06:59 AM »

Time to start making some sort of hub for it..

...starting with a scrap of mild steel bar.

Roughed out with a hole in the middle...

Then turned down a bit of a rusty old bolt for a squeeze fit in the...

...hmmmmmm... not quite as firm as I would have liked but it is snug.

The first bit goes back in the lathe and one hub cheek is roughed out and ...

... parted off.

Here are the bits so far, the rotor wheel, a hub cheek, the original bit of bar used as a mandrel..

.. and of course the bit of old bolt that will be pressed in to hold everything together then sawn off. Loctite in case the fit is not really tight enough?

Everything pressed together and in the vice for the Loctite to cure.

Meanwhile....

... the first bearing cup is being parted off.

sbwhart · « **Reply #3 on:** March 08, 2009, 01:53:53 AM »

This is intreaging me

can't wait to see the finished job.

Nice to see your adding more photos John

Keep the posts coming

Cheers

Stew

Brass_Machine · « **Reply #4 on:** March 08, 2009, 03:55:43 PM »

Waiting for more

Eric

John Hill · « **Reply #5 on:** March 12, 2009, 03:52:16 AM »

The Artful Bodger gets ready to try something scarey!

I need to cut a slot in the end of that bar, the block of steel in the 4 jaw has a 'V' in it so the bar is securely located.

I have ground a HSS tool to cut the slot and tomorrow, if I can pluck up the courage, I will cut the slot, I have 8 of these to do if it works out OK.

Obviously I have to take really fine cuts but what is the recommendation, dead slow or a few hundred RPM for this type of interrupted cut?

Stilldrillin · « **Reply #6 on:** March 12, 2009, 04:38:31 AM »

Oooooh, John!

That look seriously scarey to me.

I wouldn`t dig straight in........

Can you rough out the slot with a hacksaw, before turning?

Can you rough out with a milling cutter in the chuck, & the component in the toolpost?

Be very carefull....... Please!

David.

bogstandard · « **Reply #7 on:** March 12, 2009, 05:04:51 AM »

Yes John, certainly scary.

It is not the plunge cut that will cause the problem, but the interrupted cuts. The lathe tool nose will take hell of a bashing.

I am not saying you are wrong, as you have no other way of doing it, just take your time and get ready for anything that happens all of a sudden.

It might go smooth as silk, and all our gum beating will be relegated to useless info.

Give it a go, but win or lose, let us know how you get on. Don't be afraid of failure, and boast about your successes.

John

Brass_Machine · « **Reply #8 on:** March 12, 2009, 07:25:26 AM »

As Bogs said, just be extra cautious when you are doing this.

Eric

sbwhart · « **Reply #9 on:** March 12, 2009, 07:34:16 AM »

Hi John

That looks like a brown trouser job.

Don't stand in line with the spinning job, stand to one side and slowly does it.

Good Luck and interested how you get on.

Stew

Darren · « **Reply #10 on:** March 12, 2009, 07:36:07 AM »

I'm not sure I like the look of this, that's going to be some pressure on the chuck jaws as well as whacking the heck out of the cutter.

If you were in the UK/US I'm sure an offer of help would come about....is there no-one in NZ you can turn to?

Just go very gently and slowly, though the lathe will need enough speed to actually make the cut.

kellswaterri · « **Reply #11 on:** March 12, 2009, 07:50:16 AM »

Hi John, have you thought of this set up...removing the tool post ...clamping the job to the top slide and using a milling slot cutter in the chuck to mill out the slot...much safer than trying to turn it out

...Just a thought,
All the best for now,
John

sbwhart · « **Reply #12 on:** March 12, 2009, 08:01:19 AM »

John the other John just about beat me too it. above is a Crap O cad of another way you could do it in the lathe as John just suggested.

Cheers

Stew

John Hill · « **Reply #13 on:** March 12, 2009, 02:04:36 PM »

I wasnt really scared but now I am terrified!

There is all today to think about this as garage playtime is in the evening. Thanks for the comments.

I suppose I could buy a mill cutter and lash up something to do it, I suppose I could drill 60% of the material out in advance.

Of course I could ask Sally Shaper to do this job but it looks a tall order for such a small machine and I am yet to master slot cutting with her.

However there is a certain advantage of the turning method if I can do it and that is the radius of the cut will match the piece that these slotted bits have to mate with.

kellswaterri · « **Reply #14 on:** March 12, 2009, 03:11:44 PM »

there is a certain advantage of the turning method if I can do it and that is the radius of the cut will match the piece that these slotted bits have to mate with.

John, I am some what confused,easily done these days

but how would that work?
All the best for now,
John.

John Hill · « **Reply #15 on:** March 12, 2009, 04:42:43 PM »

Quote from: kellswaterri on March 12, 2009, 03:11:44 PM

there is a certain advantage of the turning method if I can do it and that is the radius of the cut will match the piece that these slotted bits have to mate with.

John, I am some what confused,easily done these days but how would that work?
All the best for now,
John.

All will be revealed John.

John Hill · « **Reply #16 on:** March 13, 2009, 04:00:18 AM »

Much to noone's suprise I am sure but the turning project had to be abandoned.

The tool cut the end of the bar OK and although there was some chatter it was not serious. What caused me to abandon the process was that there was too much strain on the fixing in the lathe and just the slightest bit of movement there spoiled the shape of the cut.

[Besides, I broke the carefully ground tool that was exactly the width of the required groove.]

sbwhart · « **Reply #17 on:** March 13, 2009, 05:35:35 AM »

Good try John

What's your plan B?.

Stew

sbwhart · « **Reply #18 on:** March 13, 2009, 05:54:45 AM »

John Here's a suggestion for plan B or should that be plan BBB

Do it with a fly cutter held in the lathe chuck' and supported by a running centre in the tail stop, You'l have to make the tool holder but that won't be too difficult, the hardest bit will be filing the square for the tool bit, try and make the whole thing nice and stubby and robust. How deep do you want to go ?.

Cheers

Stew

Stilldrillin · « **Reply #19 on:** March 13, 2009, 09:31:15 AM »

Very good idea, Stew!

David.

John Hill · « **Reply #20 on:** March 13, 2009, 03:41:17 PM »

Yes Stew, I think that is a very good idea and not too hard to manage and I wont need a square hole if I use a round piece of tool steel.

I will loose my ability to machine a radius to fit the matching bit but maybe that can be tolerated (somehow).

This would certainly be more attractive than my (previously) current plan which was to have a hearty breakfast and break out the file chest, will no doubt do a better job too!

I had wanted to go about 10 mm but half that would be enough to get a secure fit, slot is about 5mm wide.

Stew

and of course

Maybe later today (Saturday here and a few chores to get out of the way.)

sbwhart · « **Reply #21 on:** March 13, 2009, 03:52:56 PM »

John

When you make the tool holder remember to drill so the tool is cutting on centre its a mistake

I always make when doing that sort of job.

Good luck

and have fun

Stew

John Hill · « **Reply #22 on:** March 14, 2009, 01:35:07 AM »

Bodger makes progress.....!

Fly cutter, as recommended by Stew, chops its way into the work...

Work parted off and now turning a bearing cup..

Bearing fits nicely!

Tried for size on a gimbal ring.

Doesnt look too bad, even if I say so myself!

sbwhart · « **Reply #23 on:** March 14, 2009, 02:22:34 AM »

That looks real cool

I can see what your making now John.

More More More.

Stew

kellswaterri · « **Reply #24 on:** March 14, 2009, 07:12:16 AM »

Hello John, now a litttle less ''confuddled''that I can see what you have made...very good job too...
All the best for now,
John

Darren · « **Reply #25 on:** March 14, 2009, 07:18:27 AM »

That's looking good John,

Nice to see what you are making

Glad the cutter worked for you, where there's a will.....

bogstandard · « **Reply #26 on:** March 14, 2009, 08:33:24 AM »

Here you are John, a bit more inspiration, and what you can get up to with them.

http://www.gyroscope.com/

Coming along very nicely BTW.

Bogs

Bernd · « **Reply #27 on:** March 14, 2009, 08:48:02 AM »

John,

Nice background when you took those two last pics. Makes it very easy on the eyes.

I was looking for were you joined the ring together to get the flywheel on. Can't find a joint any were.

Nice job by the way.

Bernd

John Hill · « **Reply #28 on:** March 14, 2009, 04:53:40 PM »

Thanks for the comments guys.

John (Bogstandard), they do not have any there in the configuration I have in mind but a very interesting site, however 40 quid for one of theirs?

Bernd, there is no join in the ring, and the shaft ends have steps where they enter the bearings.

Bernd · « **Reply #29 on:** March 15, 2009, 05:53:18 PM »

Quote from: John Hill on March 14, 2009, 04:53:40 PM

Thanks for the comments guys.

Bernd, there is no join in the ring, and the shaft ends have steps where they enter the bearings.

John,

I was joking about that. It was a compliment as to your work skills.

Bernd

John Hill · « **Reply #30 on:** March 22, 2009, 04:27:25 AM »

Dont worry folks the gyroscope has not been forgotten! I managed to find a small butane torch today which I need to do a little soldering (brazing maybe) on a couple of the gimbal mounts. So I will be back onto that project right soon!

Brass_Machine · « **Reply #31 on:** March 22, 2009, 11:52:26 AM »

Quote from: John Hill on March 22, 2009, 04:27:25 AM

Dont worry folks the gyroscope has not been forgotten! I managed to find a small butane torch today which I need to do a little soldering (brazing maybe) on a couple of the gimbal mounts. So I will be back onto that project right soon!

Very good. I will try to be patient for a little while longer.

Eric

Darren · « **Reply #32 on:** March 22, 2009, 02:17:59 PM »

Yes it was coming on so well too....

John Hill · « **Reply #33 on:** March 28, 2009, 01:18:49 AM »

Who is a grumpy boy then? I bought a small propane torch which I was told, and the picture on the box confirms, that it would have enough heat for hard soldering, in a pig's ear! So back to the old fall back of soft solder..

...so out to the 'dirty' workshop where there is a vice big enough to hold the ensemble and with the biggest electric iron I have the solder flowed and the joins were made.

Unfortunately to get good heat transfer with soft solder it is necessary to put a little pool of solder where the iron contacts which later has to be cleaned off and with solder on the surface there is no prospect of doing the original intended finish which was a black oxide (gun 'blueing'), oh well, I am sure the lacquer will look very nice!

... just enough time left in the day to do a trial assembly on a bit of old fibre board.

sbwhart · « **Reply #34 on:** March 28, 2009, 02:29:50 AM »

Wow nice job.

I noticed you've got some holes drill to balance the fly wheel, what method did you use to get the balance.

Cheers

Stew

John Hill · « **Reply #35 on:** March 28, 2009, 02:53:33 AM »

Stew, I just spun the wheel and marked where it stopped, it is still not right but I can spin it really fast without vibration, much.

sbwhart · « **Reply #36 on:** March 28, 2009, 05:30:42 AM »

Ho I see:- if stops in the same place it out of balance random stop its ok.

Cheers

Stew

Twinsquirrel · « **Reply #37 on:** March 28, 2009, 05:37:32 AM »

Looking good John! I may be, well I am, jumping the gun a bit here but how are you gonig to spin it up? Dremel as in the link you posted earlier or string etc?

Cant wait to see a vid of it running up!!

David

Bernd · « **Reply #38 on:** March 28, 2009, 08:28:33 AM »

John,

I find it hard to believe that a propane torch would not heat up that amount of metal you show, yet an electric soldering iron has enough heat to soft solder.

How about a pic of the propane torch? When you say small I'm thinking one of those butane pencil torche sizes.

I would think a torch of the size I have pictured below would handle the size metal you are trying to silver solder.

I used a bottle of my favorite

to show the size of the torch and then noticed in the picture that it is marked with the size on the propane bottle. Amazing what you can see by having one early in the morning.

Regards,
Bernd

John Hill · « **Reply #39 on:** March 28, 2009, 04:03:14 PM »

David, piece of string method. Of course I could give it a blast of compressed air but I wonder what the safe speed of a rivetted mild steel wheel would be.

Bernd, it is the torch that is too small, not the bottle!

John Hill · « **Reply #40 on:** April 11, 2009, 10:26:22 PM »

Ahhhhh!

bogstandard · « **Reply #41 on:** April 11, 2009, 10:59:40 PM »

Well!!

sbwhart · « **Reply #42 on:** April 12, 2009, 12:49:58 AM »

Video ???????

John Hill · « **Reply #43 on:** April 12, 2009, 01:13:52 AM »

Sorry, I cant manage a video, I only have narrow gauge 'broadband' and I do not have a video camera.

I got it up to a few thousand RPM by repeated stroking with a cord, it goes well enough to demonstrate the principles but there are many aspects to the balancing of the gimbals that are not quite right.

OK for the shelf though!

sbwhart · « **Reply #44 on:** April 12, 2009, 01:32:44 AM »

Well done that man

It looks a nice job

I'd thought you'd have gone for a more of an ''all black look''.

Getting things balanced correctly is a bit of a black art you've got static balance and dynamic balance, and then you've got different harmonics of vibration thrown in for good measure, I don't understand the physics (let alone spelling it) but I know you get effects from these factors.

Good interesting project I really enjoy following it.

What next then

Stew

John Hill · « **Reply #45 on:** April 12, 2009, 02:04:43 AM »

The challenge with a fully gimballed gyro such as this is that it must be balanced so that it will rest in any position. Then of course the rotor must be balanced.

Spinning the rotor does demonstrate its tendency to maintain the same axis in space but if there in any imbalance in the gimbals tending to change the axis the gyro will 'precess' (I think thats the word) and will tend to move in a direction at 90 degrees to what one would expect!

Stilldrillin · « **Reply #46 on:** April 12, 2009, 03:31:19 AM »

That`s nice John.

Well done.....

David D

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Author Topic: The Artful Bodger tries to make something! (Read 31430 times)

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