Member postings for Andyf

True, if you want to put the dot dead centre in (e.g.) an existing finished diameter. But if you are leaving that until afterwards, a dot which is few thou out won't matter, will it? Surely the idea of these devices is to enable the chuck to be adjusted to get the dot centred..

Andy

Sorry to read of the death of your grandad, Bev.

Maybe a local Model Engineering Soc. might be a good place to enquire. If your grandad was ever a member of one, that would be a good place to start. Otherwise, there's one in Oxford , and if that's a bit far away, a pretty comprehensive directory here.

Andy

Jerry,

Like Thor, I favour the sort which is supported by a centre in the tailstock, and using an indicator on the end near the workpiece. I made one; picture here. The cannibalised dart is soft soldered to the brass tube, with a spring between it and the steel rod to hold the device in place.

In no way is it concentric, but as the friction between the rear end and the centre is far greater than the friction at the pointy end, it doesn't revolve and concentricity isn't an issue.

After taking the pic, a 1" slit was cut along the side of the tube, to take a pin into the rod, so the thing can't fall apart. All very crude, but works a treat.

If making one like your sketch, consider mounting the long rod in something springy, like through the hole in the end of a piece of old hacksaw blade sticking out from the toolpost. That would save the bother of a ball joint. It does strike me that the rod, which might be rather slender and prone to getting bent, must be dead straight to line up properly with the tailstock centre. But why bother lining up with a centre? Simply adjust the chuck until the far end stops waving around in little circles. Then, a bent rod wouldn't matter.

Andy

I reported it overnight, too, and the post has gone. The advert is still there, though "Chengdu" will lead most folk to realise it's a business trying to get free advertising space.

Andy

It occurs to me that if the requirements for no appreciable "noise" getting on to the recording are to even approach those mentioned by Michael Williams yesterday, you may be hard pressed to find a screw which has no tiny imperfections on its threads which take the noise outside those limits.

Andy

No, Mike, but threading dials are really easy to make. Mine (for an inch leadscrew) has a PVC(!) pinion, fashioned with little regard for the niceties of pressure and helix angles, and I've been using it on and off for 5 years. A metric leadscrew usually needs more than one pinion (often 14T, 15T and 16T or a multiple of each, if I remember right) in which case it's probably easier to make separate dials than to put the pinions on a common shaft and find a way to engage the one you require for a gioven thread pitch.

Andy

PS I suppose I should have called them worm wheels rather than pinions.

"Thanks for all your suggestions but what wife really wants is a hands free voice activated system. I think she may have to dream on."

Can be done; it's known as VOX or Voice operated transmission, where your voice (or any loudish noise) replaces the press-to-talk switch and switches on transmission. I have a handheld dictating machine with the equivalent; it records when you talk, though there is a moment's delay so it's best to say "Boo" to start record.

However, I don't think any of the cheap licence free PMR446 walkie talkies offer VOX, though some expensive ones do.

Andy

Oops! Posted before coffee. Sorry, Roger.

Andy

Can you give your approximate location, Roger? Difficult hooking up with someone in Penzance if you are in John o' Groats.

Andy

Been cloudy all day here in NE Cheshire. Met Office says the max was about 19°C/67°F. Got a bit done in the garden, so quite thankful for the coolth. Still rather cloudy tomorrow, apparently, but hot with it. Deluge (weather warning posted) on Tuesday.Still, the car does need a wash.

Andy

I'd forget the grubscrew. It, via the bit of brass, will only have line contact with the supporting rod.. Something which grabs the rod all the way round like a boa constrictor would get a better grip. Like the one in the middle of the top row in this picture.

Andy

I suppose that, if comms are to be one way, a wireless baby alarm would do the trick. She has the baby's end (transmit) and you have the receiver. That means you can't answer back, though.

As David says, cordless phones with 2+ handsets usually have an intercom button on the base station (the one that sits next to your master socket) which will ring the outlying set(s), whereupon you can pick up in your workshop and explain that you are in the middle of something really complicated and can't help just now. Something like a "Panasonic KX-TG6481 Twin" (a "Which" Best Buy) will set you back about £53, with a handset on the base station and another one for the workshop. Also means you can make/answer ordinary phone calls from within the workshop. I have a 3-handset BT job, one in the traditional place in the hall, one by the bed and one in the garage. Also have another two hard-wired extensions in kitchen and living room.

Andy

I dion't know about here in the UK, Roger, but LittleMachine Shop in California sells them, and will ship across the pond. Try this page, pick the first one and then click on Chris's Tips, where you will find a link to a chart showing the inserts and their LMS part numbers.

I suppose they will all be 60°, so no good for Whit, BA etc.

Hopefully, you will find a UK supplier.

Andy

Edited By Andyf on 20/07/2013 14:38:19

I think the furniture pads will be artificial fibre, Clive. Burn a bit of the fibre, and see if it smells like burning wool. You could do with with an old felt hat to cut up.

I wonder if felt strips could be wound round the wooden taper, like a fairly coarse taper thread. Turn the thing while gently inserting it, then pull it straight out. It might have more chance of dragging out chips that way than if the strips were longitudinal.

Andy

Geoff, I should have preferred the radio show to say a bit more about the contributions he made to physics and other aspects of science and technology, rather than saying "Feynman was really bright guy" and then concentrating on examples of his (sometimes eccentric) funny side.

I'm sure that if I knew nothing about Einstein and his theory of general relativity, then heard a radio show about him which went into it, I'd realise (even if it was a bit over my head) that Albert was a bit clever. Wouldn't you?

Andy

Not sure whether to say thanks for the link; got interested and spent a couple of hours reading it through. Still, it was a bit too hot for anything else this pm.

There was a good program about Feynman on Radio 4 some time in the last year. He sounds a terrific guy, though they did tend to concentrate a bit too much on his eccentricities rather than his intellect .

Andy

Bob, as the person who started this hare running, I'm sorry for doing so. Comes from being a retired lawyer all my working life (retired now, so recovering slowly) and the holder of a firearm certificate, I suppose.

Please don't stop. I'm sure most folk, like me, want to see more of the skilled workmanship which is going into this model.

Andy

When I actually use it, I apply coolant sparingly with a brush. I got tired of getting go-faster stripes up the front of my shirts.

Andy

I think the problem on that threadf has gone now, and that it was caused by the original photos being rather large. For me, the same occurs if photos appear side by side, rather than one beneath the other.

Andy

The computer fan is a good idea. As a result of someone else's tale of releasing the magic smoke, I shoehorned one on the end of the motor on my little Warco lathe, which has vents in both ends. It runs continuously from a 12V wall wart when the lathe is switched on at the wall socket, and gives a good breeze through the motor. When running at low speed and highish torque, the motor's own internal fan is needed most, but isn't doing much to help.

Andy