Member postings for pgk pgk

As I thought... so perhaps a pointy cutter with a depth stop bearing each side and a push spring so it chases the groove to correct depth... a bit like router cutters?

How about fitting the ring to a mandrel, off-centre drilling each end then setting it up between centres to make the groove?? I'm not sure my spacial awareness is good enough to postulate whether the groove ends up even or some sort of elliptical depth...

Ideally i would have made the main block to which all the cylinders attach next but it's quite a busy part and I decided to invest in some layout fluid..post pending.. to reduce the dumbo moves I'm likely to make.

Shop time has been scarce 'cos wife is away with granddaughter and that leaves me with all the farm and house chores solo and I don't like to abandon the dogs alone in the house for too long at once.

This was the next part:

I had a long think about how to do this. I'm after a mirror finish without jaw marks and aiming for both sides parallel. I'm sure there's lots of ways of doing that...pleased to hear of better ones too.

I decided to use the 4-jaw so i could pop some shims between jaws and part and use the whole length of bar rather than cutting and wasting bits.

I got too excited over boring the through hole to take pics but I used one of the boring tools from my mill boring tower fitted into a QCT holder and got a lovely finish. Parted off some 3 mm longer than the drawing and then over to the mill to mill the flats and place the bolt holes with plenty of counterbore.

I found a squared up scrap block I'd dumbo'd on a different project and drilled & threaded that to bolt too.. indicated in the 4-jaw I got the centre bore set without a flicker on the needle. That worked out well.

I think the best alternative might have been to make up some soft jaw covers and turn the proud side first with enough to get a grip on but that or fitting it to a mandrel left me concerns that the part might be canted on it's face?? Setting it up on the faceplate would have needed a back board or plate and a mare to indicate compared to the 4-jaw...?

Re: painting it I turned this up on a search. **LINK**

Athough painting lexan suggests the rc car paints ought to work too.

The practice paid off.. got quite quick at making them at last...

Hmm.. this could be the start of a new forum section .. a 'how not to build' thread..

Yesterday i started on the tiny conrod? axles on the crank webs. Someone was questioning the use of ER32 collet chucks. Well that had to be my way to go 'cos my 3-jaw doesn't grip 3mm.

The part is 10mm long, 3mm diameter and a 1mm wide flange of 5mm dia 4 mm from one end and an M2 thread in the short end. Talk about fiddly and not helped by my smallest stock being 1/2 inch and just to be awkward whatever variant of mild steel it is I couldn't get a nice finish with power feed on either of two different indexable tip types or two different HSS grinds. The acceptable solution was actually a tediously slower hand feed than the slowest powerfeed option.

A length of 5mm dia made up eventually and the first part turned out. Rookie mistake again. I turned the 3mm diameters dead nuts then cut the M2 thread..locktighted into the crankweb and discovered that the short end had spread a touch from threading and was now over the 3mm....Doh!

The second part was turned out ready for tapping..whereupon the centre drill tip snapped off embedded in the shaft. I called it a day.

Ho-hum. Just remake that second axle. Except that I wasn't happy with the oversize first one so a touch of heat should get it out and adjust. Not with the z-71 red threadlock brand I'd used! By the time i got it out it had blued the steel and the needlenoses had marked it..

Still i need the practice making this tiny parts....

The only borosilicate I've tried cutting was these boiling tubes. It was hugely interesting to see the effect of various cutting discs.. the brown and black dremel types essentially melting the glass at the interface from friction.. to the stage of a bright white point of light there- create a groove but never cut through. The whole point of such glass is to cope with thermal 'shock'. It is supposed to have a more flexible molecular structure than ordinary glass - so I'm guessing here - that in a sheet form it either takes a much bigger shock to trigger a crack to run or perhaps at a colder/brittle temp or cut in a semi liquid state with shears??

It's noteworthy that old glass is harder to cut neatly then fresh glass too. Ancient greenhouse glass is a real pig to recylce by cutting.

..unless some other phenomenon is at play?

At one job the only way i could get a readable ECG trace was with the patient positioned N-S. Any other direction and the baseline oscillations on the trace made it unreadable. The proximity of ley lines, my boss's antimagnetic personality or the electrified railway at the bottom of the garden were all considered causes..

Where i live now there's a 600ft ridge just across the field. One day i shall find the energy to climb it and recover all those small parts missing from my shed. I'm convinced of the mass attraction that causes them to vanish.

Fast spinning objects may well be communicating with an alternative reality.. why in some places you can put a pair of socks in the spin drier and only ever recover one sock. It's no stretch to consider a perfectly spinning gyroscope can also exhibit abberant behaviour <s>

On my first set of stand arms I used mild steel filing buttons and didn't like the result.. just not neat enough. I then made up a set of hardened buttons of slightly smaller diameter to try and salvage the parts (my first at hardening silver steel) but my filing wasn't neat enough and i ended up with a sort of neck where the bearing rings met the arm length. I've just finished remaking them and this set are acceptable; a good press fit on the bearings but again the problem was with the handwork where the rings part meets the longitudinal; I found it hard to file that junction and it took ages.

The crank webs now need reworking or remaking - a similar problem with neatness at the internal angles before i move on.

But was that with borosilicate glass? Certainly for ordinary glass creating a weaker point then thermally shocking it can work well... there's suggestions for cutting bottles with accelerant soaked string and tieing around, lighting it etc... or a scratch then pouring boiling water over the area. For ordinary fresh window glass a simple scratch and tap is classic. Along the way before i used the diamond discs I did try scoring and tapping the tubes...just a mess.

I went on to make the crank webs next...twice because i didn't like the first ones. Then i sat back and looked closely at the parts i've made and decided they aren't really neat enough so back to square one and I'll remake them again...

..it's a slow learning curve for me.

Edited By pgk pgk on 09/12/2015 10:32:50

I also have a MT5-3 adapter and use the MT3 ER32 from my mill in the lathe.

You can hardly feel a mark on them with fingers or fingernails but they still show tool marks. Since they're scheduled to be painted.....

On to the next part..

Ian, I have no doubt you're right...I just need a heck of a lot more filing practice and likely some better files.

I've not got much done..simply because i got bogged down in calculations for the support frame arms. The drawing supplied wound me up some being determined to work things out from the figures given.. until I realised that the only important dimensions were the spacing between bearing centre and distance to pivot point and the rest was really just artistic. Nevertheless i was determined to solve the figures on making a duplicate and wasted ages doing so before I 'cracked', 'cheated' and displayed the original pdf at several hundred percent on screen and measured the angles of the arms off the screen. I've finally dimensioned it all and ready to start cutting.

It would have been a lot quicker just to draw the arms out on a piece of plate and roughed it with a decent bandsaw then filed the rest but i've been using the mill dro rather than marking (don't have good height gauges or surface plates yet) and I'd already cut 2 strips and glued them together.

This is a learning experience for me as well as brain excercise.

I challenge anyone to dimension that drawing without guessing at at least 2 figures or measuring them off the original plans

My daughter took degrees in English and kept insisting to me that 'language is organic'. I followed by arguing that it's insubstantial and unbestowed of any life apart from that anthropomorphised upon it.

'Organic vegetables' is my personal hatred in terminology. Where can i buy inorganic veggies?

Today I went in search of a better finish. As stated before I have bags of hot-roll plate but I don't like the mill finish .. that corrugated look after several furrows to thickness and I'm not very good at sanding them out. Ues the belt sander gets rid of them or enough patience with a sheet of abrasive and a flat surface but however you hold or rotate there will always be more coming of the edges than the middle...unless someone has a better way??

I bolted a 6mm plate to the backplate of lathe. This gave a diagonal of some 8-9 inches. With a carbide insert I could get a mirror finish on the outer part but once surface speed dropped as it moved across the face the finish fell off too. Is it reasonable to stop the lathe mid cut and change speed? Does it work or leave a transition ridge?

Anyway I tried with a facing tool in HSS.. and then ground a new one to see if i could do better still. The best i can say after several hours messing about is that the finish is 'OK'. It's better than mill but not mirror. I'll chop the plate into needed bits and start on the stand tomorrow.

There's a chance I might actually get some building done.

Pics of successfully cutting the glass and the misting unit and attachment to my mill:

I freely admit to some sloppy writing at times..and appalling typos. But this phrase from the BBC news site shows how standards are dropping everywhere.

These "proof masses" will be allowed to free-fall inside the spacecraft, and a laser system will then attempt to monitor their behaviour, looking for path deviations as small as a few picometres. This is well less than the diameter of an atom.

A bit of 'googling' found this (scroll down for the metric ones) **LINK**

And on aliexpress **LINK**

pgk

Just a valve on the air side (1/4 or 1/2 turn - can't remember which). Set it too low and the coolant flow (suction) stops but still a decent air blast. Not used in anger yet. It may well be a case of having to take breaks to allow my lidl compressor to catch up. the nozzle has some adjustment too.. haven't played with it but probably just the spray shape.

hopefully I'll load some pics of how I attached it