What did you do today (2015)

[BowberParticipant @bowber]

Posted by John Stevenson on 22/07/2015 11:39:21:

Yesterday actually.

Took a little 4" table belonging to a friend and fitted a stepper motor to it.

is only a cheap table and very basic in the build up but it's all he has.

Came out better than I thought it would on backlash give the crudeness of it. Think he'll be quite happy with it.

I did the same on my 6" table from Chronos, came out very well and has the added benefit of having adjustable backlash (I think its really just to disengage the drive) I also only go one way usually unless it's a rotary 3D job.
I don't usually bother with the table locks either and have had no positioning trouble.

Steve

[Neil WyattModerator @neilwyatt]

Chrome…

Never mind, here's something more engineering related. "The Techno Trousers EX-NASA are a special pair of robotic pants with many properties. They were given to Gromit on his birthday by Wallace in The Wrong Trousers. The Techno Trousers have the ability to adhere to any solid surface via suction, enabling the wearer to scale the side of a wall. This however, was not their original purpose."

NASA's Techno Trousers:

Are now a reality:

[Ed DuffnerParticipant @edduffner79357]

My Brother called today and asked if I could make a replacement ram for a hydraulic track tensioner on a mini digger. Just a basic cylindrical part approx' 30mm dia' x 80mm long. The original has become pitted and won't seal properly.

The stock supplied is a piece of pneumatic drill chisel with hex cross-section. My little WM-180 seems to be up to the job and I'm using carbide insert tools with surprising success so far. The job is in the lathe cooling down, ready for final cuts tomorrow.

Here are a couple of photos of the original cylinder and ram [piston?] . I wondered whether some JB-Weld could be used to repair the pitting in the old part and just skim it back down to size.

A close-up of the pitting.

Ed.

[Phil WhitleyParticipant @philwhitley94135]

You might be able to sandblast it then metalspray it, is is fairly badly pitted, no wonder it didn't seal! If it is turnable you could clean it up and shrink a sleeve onto it. There is always a way, the question is are you putting more time and materials in than it would take to make a new part?

Phil

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Neil Wyatt on 22/07/2015 11:45:45:

Remember the stereo loco pic a while ago?

Stereophotography is a passionm of Brian May and when he visited Nasa recently he fiddle with some pluto images to make this:

Right click and 'view image' then zoom in and out to get a comfortable viewing size.

.

Definite stereo effect achieved on the iPad [using a simple pinch-zoom], but the shape looks more like the nose of a torpedo, than a sphere … Nice try though.

MichaelG. [still boggled by the achievements of New Horizons]

[Frances IoMParticipant @francesiom58905]

the two images are in the wrong order to allow the simple cross-eye’d mechanism to work – produce a new image with the current rh image transposed to the lha and it becomes very effective.

[Anonymous]

Ran through the maths to prove to myself that the 'number' of teeth used to select an involute gear cutter for cutting a helical gear is equal to the actual number of teeth divided by the cube of the cosine of the helix angle.

What I haven't understood yet is the additional term (quoted in Machinery's Handbook) for high helix angles and low numbers of teeth that involves the PCD of the cutter itself.

Andrew

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Frances IoM on 22/07/2015 23:02:15:
the two images are in the wrong order to allow the simple cross-eye'd mechanism to work – produce a new image with the current rh image transposed to the lha and it becomes very effective.

.

… But the correct order for parallel viewing

I can't do cross-eyed, but 'gazing into the distance' comes easy.

MichaelG.

[Neil WyattModerator @neilwyatt]

Posted by Frances IoM on 22/07/2015 23:02:15:
the two images are in the wrong order to allow the simple cross-eye'd mechanism to work – produce a new image with the current rh image transposed to the lha and it becomes very effective.

On another forum someone swapped them over; I can do it both ways, but the crossed over one is easier without an aid for some as you can have the image bigger and further from your eyes.

Neil

[Ed DuffnerParticipant @edduffner79357]

Posted by Phil Whitley on 22/07/2015 21:36:53:

You might be able to sandblast it then metalspray it, is is fairly badly pitted, no wonder it didn't seal! If it is turnable you could clean it up and shrink a sleeve onto it. There is always a way, the question is are you putting more time and materials in than it would take to make a new part?

Phil

Thanks for the suggestions Phil. I only have basic gear at the moment, although metal spraying and brazing did cross my mind [saving the pennies]. As you mentioned the minimal cost to make a new one outweighs the exotic repairs which is why I wondered about JB weld.

Regards,
Ed.

RE: Pluto, I tried to view it through the scope once and managed to get just a very faint grey fuzz in the centre of the view finder with a high power eyepiece. If anything it proved the GPS works ok, assuming it was Pluto I was viewing.

[Michael Cox 1Participant @michaelcox1]

I have read Harold Hall's articles on his website about soft jaws and their uses. They seem to be very useful for some types of work holding. My mini-lathe only has a cheap 100 mm imported chuck and there are no soft jaws available for it..

I have an idea that enables soft jaws to be clamped onto the outside jaws of the chuck.

The photo shows the soft jaw on the chuck.

This shows the soft jaw removed from the chuck. Note the M6 grubscrew on the right hand side. This is used to clamp the jaw onto the outside jaw.

The soft jaw clamps onto the outside jaw as shown above.

This shows the underside. The milled step clamps against the first step of the outside jaw.

So far I have only made one prototype jaw to test the concept and it seems to hold well. I have ordered material to make a full set of 3 jaws.

Is this a new idea? Does anyone have any comments? Can anyone see any pitfalls?

Mike

[David Clark 13Participant @davidclark13]

As the hexagon is above the jaw leverage might be a problem. Probably ok on light cuts.

[Roderick JenkinsParticipant @roderickjenkins93242]

Posted by Andrew Johnston on 22/07/2015 23:04:02:

Ran through the maths to prove to myself that the 'number' of teeth used to select an involute gear cutter for cutting a helical gear is equal to the actual number of teeth divided by the cube of the cosine of the helix angle.

What I haven't understood yet is the additional term (quoted in Machinery's Handbook) for high helix angles and low numbers of teeth that involves the PCD of the cutter itself.

Andrew,

I assume that the additional term is to take account of the fact that we are using a rotating disc to cut the teeth rather than planing with a single point. The circular cutter interferes with the tooth form away from the contact point and this becomes worse as both the helix angle and the cutter diameter increases. The interference will tend to widen the cut away from the true form (thereby narrowing the tooth) so we need to choose a cutter for a narrower tooth form. I'm afraid my geometry skills are far too rusty to derive the term so I'm relying on you!

Rod

[OuBallieParticipant @ouballie]

Neil,

I'll become permanently cross-eyed if I continue looking at that bl@@dy Pluto photo

Geoff – Only see triple

[Nick_GParticipant @nick_g]

.

I will be fitting these to my motorbike later.

When working on brakes is it just me that somehow ALWAYS gets the taste of brake fluid into their mouth no matter how careful they are.

Nick

[Alex CollinsParticipant @alexcollins55045]

On a wet n windy Friday what could be better than a visit to the local High St Electronics retailer….
It's great when does not match what the website says…..

Anyway. TI Launchpad and Bluetooth modules bought online.
The rest I got this morning. Not bad for a days work.

Credit to **LINK** for the build plans.

[Anonymous]

Posted by Nick_G on 24/07/2015 12:13:27:

.

When working on brakes is it just me that somehow ALWAYS gets the taste of brake fluid into their mouth no matter how careful they are.

It is just you you surely don't suck fluid through to prime them when fitting new braided hoses do you ???

[Colin HeseltineParticipant @colinheseltine48622]

Alex,

That looks good. I recently built the quadrature one to use with magnetic read heads on my Cowells mill. It works very well. It was my first time building anything electronic in 54 years. I had fun working out positions for the various resisters. Being red/green colour blind does not help, digital multimeter helped no end. Still very nervous when powered it all up.

It all fitted in a Maplins box with three 9 pin sockets on the front. I managed to use some plastic lightpipes to bring the LEDS from the TI Launchpad board to the top cover of the box so I can see when it is powered up and comms is active. You can see my circuit board attempt above.

Best of luck with yours, having DRO's is great.

Colin

[Nick_GParticipant @nick_g]

Posted by Mick Berrisford on 24/07/2015 18:44:33:

Posted by Nick_G on 24/07/2015 12:13:27:

.

When working on brakes is it just me that somehow ALWAYS gets the taste of brake fluid into their mouth no matter how careful they are.

It is just you you surely don't suck fluid through to prime them when fitting new braided hoses do you ???

.

Noooooooooooooooo. Even I am not that stoooopid.

Nick

[Anonymous]

That's alright then ……. weird though, I've always thought of brake fluid as pretty "neutral" can't remember it ever registering as a taste/smell and I've done a fair few strip and replacements.

[John Stevenson 1Participant @johnstevenson1]

Posted by Mick Berrisford on 24/07/2015 22:36:25:

That's alright then ……. weird though, I've always thought of brake fluid as pretty "neutral" can't remember it ever registering as a taste/smell and I've done a fair few strip and replacements.

.

The stuff is evil, definitely has a taste.

Tastes like most French red wines.

[Jesse Hancock 1Participant @jessehancock1]

John I know what you mean. Their mustard is crap too.

[MikeParticipant @mike89748]

Just finished building a KMX recumbent tricycle from a flat pack from the manufacturer, KMX Karts. See the beast at **LINK** Reason is that, following a stroke, I lack the balance to ride a bike. Wish I'd bought one years ago – this thing is great fun, and adds to my reputation as the village eccentric – which is maybe just one step up from village idiot!

[Roderick JenkinsParticipant @roderickjenkins93242]

They're great fun! I had a go on a friends Tadpole once. I did feel a bit invisible to artics be he manages the 10 mile commute twice a day without mishap. Enjoy.

Rod

[pgk pgkParticipant @pgkpgk17461]

I suspect it'd take a chain hoist to get my 2 meter plus backache into one of those and on my narrow rural lanes I'd probably need a reverse gear too if they have them?

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