Here is a list of all the postings andrew lyner has made in our forums. Click on a thread name to jump to the thread.
|Thread: Tapping a nylon hole.|
I decided to make an M10 thread in a nylon block to take an aluminium screw.
The nylon is very tight, despite squeezing my M10 die in as far as it would go for the male thread.
Is there a bodge that I can do to loosen up that nylon thread? Perhaps some abrasive run between the surfaces - uo and down many times? Could I do something to the leading edges of an M10 tap? I'll try anything once.
I also (not surprisingly) have been getting stringy edges and rings of nylon which I have to tear off. I have tried various tool shapes and I have read that slow and as sharp as possible is the right way. But, at the moment, the results are all a bit random.
Edited By andrew lyner on 25/11/2019 16:43:02
|Thread: Holding a 90mm optical tube to a rectangular bracket.|
Yes. I saw that table design. That would probably be more useful than just buying an angle plate (I spotted that in my trawl through Chronos etc..
The vertical milling table I bought is the standard one afaics. It's pretty sturdy but the cross slide movement will not allow it to present along the line of centres.
I am learning that there are many perfectly acceptable 'bodges' in this work as long as you use your head and don't try to eat too much at a time. They tend to take a lot longer to set up than what you can buy. That seems to be the main drawback. I guess it could be different if the lathe were a proper workshop size, doing workshop type jobs,
The recommended cutting speed for aluminium implies that a fly cutting tool will be spinning at a truly scary rate. OTOH, too low gives its own problems.
I have a length of the dovetail already but the SW Equinox ED80 has a very short length of tube between focusser and retracted dew shield so it has to be stood off from the dovetail. the shape of the dovetail extrusion is quite cleverly arranged to take a range of radii but I cannot take advantage of it. Also, that short length of contact would appear to require a nice big contact area (the two M6 screws in the tuber are only separated by 13mm or so which makes it all a bit ' sensitive' if the whole setup is to be nice and tight yet minimise stress on the tube.
It beds in really well to the radius I've made. It should 'do' I think. I must see how the star trails look.
OH boy - you have to use an album. Still it does work.
Whoops. That picture didn't post. I just tried copy and pasted it in. I could see it fine on my copy as I edited it. I'm looking for an option to insert an image but the window I get is gobbledegook. I need a file select window and there doesn't appear to be one. Any ideas?
I trip out when asked for a URL. That's something from the dim and distant past afaic.
Edited By andrew lyner on 14/11/2019 23:28:18
This is how I did it. Same idea as @JasonB's The work piece had a hole in it and sits on the tool post. There are no T slots on the mini lathe cross slide so this seemed to be the only way to clamp it.
I re-purposed an 8mm drill for the cutting tool
It was all firm enough and I was using about 300 RPM with small nibbles.
The result is not bad at all. Right curvature, fair finish and in the right place!!
I guess I could make a fitting for the cross slide with T slots but that would be hard, I think. Is there anything available on the market?
Thanks for all the input chaps.
That's what I had sketched out and just the result I want. Thanks.
My table is vertical and not as firm but I could go very slowly. There is screw adjustment that way. Did the feed in the picture use changing shims? Ah yes - feeler gauges - smart. Fitting to my cross slide could be hard;
Is that between ctrs bar something to buy? Could be expensive so it would have to be DIY. I was wondering about the problems of holding the tool and making a square hole but I guess a round hole and a round/square insert would be doable. Was thinking to cut a slot in the bar and sink the tool in it. Strong enough if the bar is solid enough I suppose.The picture doesn;t show the tool clamping unfortunately.
IF I could get hold of a 90mm grinding wheel, that could do?
I have an 80mm refractor telescope which came screwed with two screws to a bracket that has a dovetail foot. I replaced the foot with telescope rings to make it all firmer. But now I need a lighter system and seem to have lost the original bracket.
I can do the dovetail and the rest of the bracket but I need to produce a nice clean 45mm radius groove along the top of the bracket (around 30mm wide) to sit the optical tube in. I have a milling table for my mini lathe and was hoping to mill a long internal radius slot along the top of an aluminium block.
A fly cutter with a long arbor could do the job but the lathe is a bit flimsy IMO. I was thinking I could use a long sort of boring bar, supported at the tail stock end to hold it steady and use a flying cutter (carefully).
Alternatively, I could try to form a flat plate round a suitable pipe to get the curve and sit it on top of my bracket.
This is the sort of thing I could imagine would be needed to fit a cylindrical boiler for a steam engine so people must have already solved this problem. Problem is to choose the best search terms for information straight from the internet.
Edited By andrew lyner on 04/11/2019 17:34:53
|Thread: How badly do I need a surface plate?|
Many thanks for all those thoughts from everyone. Much appreciated, as usual.
I did consider the Three Plate method aamof, as it was mentioned in the Optics part of my Physics degree course. The lecturer (decades ago) seemed to imply that it was done by ancient old technicians in long brown coats and that it took days and days (he was talking about optical flatness of course).
I guess it would have the advantage that I could sell one or two of the resulting plates.
A cheapish solution seems to be the way to go. After all, it I get more fussy as time goes by, I can always step up in cost and quality.
I have watched a number of YouTube movies showing how to improve the various 'flat' surfaces on a mini lathe. They mostly seem to involve a surface plate, which is not a cheap item.
What is the alternative? I do have a number of thick steel plates. Would that be a good place to start - or perhaps some glass? Failing that, I guess I could start with the 'best' surface that's on the lathe and use that as a reference. Is that easy to measure? I have a budget dial indicator to help me.
Many people must have improved their mini lathe performance. How have they done it?
Edited By andrew lyner on 21/07/2019 10:35:23
|Thread: Aldi bargain laser level|
I got it / them - I liked the thread lock tube picture best.
But I'm still surprised no one seems to have suggested turning up a suitable thread adaptor. An excellent exercise for the student one rainy afternoon..
I thought this was a "Yes we can" forum.
Wassamadda you lathe owners? You don’t need taps and dies - just a bit of time and some gears.
Trouble is that camera equipment has been used for years and there's no reason (as far as photographers are concerned) for changing that thread standard. I would think that most photographers are not DIY people and they just buy stuff. So the standard continues. I use both sizes of thread because the small thread is not strong enough for very heavy lenses (= modest sized refractor telescopes).
The available adapters are at least as expensive as that now famous cheapo laser level.
Ian. I just found out form myself (today) that, if you put your message on the line below the verticals, it appears outside the quoted text.
And I think your laser 'level' was very good value and the same bit of tatt as the one I have!
"The above quote I find patronising and unnecessary."
I could say exactly the same about your complaint about using (well known) abbreviations. You are successfully using one part of the Internet so, instead of being grumpy about an alternative style of (informal) communication, why not just take it on board?
Using letters for well known phrases goes back to the very early days of morse so it's not a new idea.
I really didn't want to upset you.
You don't have to "fix on" two points. You adjust th sextant until the two objects coincide. It doesn't;t matter if they are jigging about.
What sort of accuracy can you rely on with your hand bearing compass and have you ever tried a HSA reading?
The RYA method uses 3 compass bearings not a sextant angle
If you have ever tried to take a fix with a hand bearing compass then you would realise the accuracy (on a rocking boat) is +/- several degrees (yes really). A Sextant angle can be measured to much less than a degree with practice. That's because you move the wheel until the two images are superimpiosed. So HSA is a very powerful tool.
I can't remember the geometry involved in using that angle to help with a fix but it's a pretty damned good method. iirc. What you see in a hand bearing compass will just NOT STAND STILL!
RYA don't expect an inshore yatchsmperson to own a sextant as everyone thinks they are for blue water trips.
Edited By andrew lyner on 15/07/2019 19:47:06
There are sooo many clever old fashioned tricks to navigating near the coast. I must say that I tended to be a bit sloppy about doing it 'properly' when there are three GPS receivers on board. Natch, to get a useful course over ground will always involve adding some nowse about tidal streams; a 'simple' chart plotter can take you very much the long way round on long passages.
I did my first coastal Nav course about fifty years ago and we had to do everything the conventional ways. GPS has its problems though. Whereas you were lucky to rendezvous with another boat in the old days, you stand a significant risk of bumping into it if you both have the same destination co-ordinates punched in.
I'd be interested to know the age at which these things cease to have validity for an individual. I have a feeling that I am by no means the youngest member here and I wonder if it's I who am out of step. I certainly qualify as a grumpy old man.
Does acronymophobia kick in when the free TV licence does? Does it kick in at State Pension time - or perhaps when policeman start looking younger?
Language is a tool and we all like to use new tools if they do the job.
That's a shame. Language is a fluid thing and, by ignoring the recent additions, you can miss out on a lot of useful stuff. If TTFN and ITMA mean something to you, then you were part of the new wave of acronyms in the past. Stay in touch; you won't regret it.
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