Here is a list of all the postings Dick H has made in our forums. Click on a thread name to jump to the thread.
|Thread: DANFOSS INVERTER HELP PLEASE|
Try **LINK**. The model without display seems to be a weirdo, see about p.33 et seq.
|Thread: Mail order ban on bladed products|
Ever cut your finger on a sheet of paper?
Edited By Dick H on 11/07/2018 21:57:31
|Thread: Age related macular degeneration.|
Many thanks to Ian for the clear explanation.
As too the injections, a friend had a brush with these injections some years ago in trying to save an eye. At the time the clinic here in S. Germany was using Avastin in an off-label use and diluting it themselves. They had patients set up on a production line, the injections had to be given under full operating theatre cleanliness conditions. Thus one vial of this stuff (Avastin) went a long way. The cost difference between Lucentis and Avastin still makes me wonder. The question was debated in 2015, with even the BBC taking notice.
As to my friend, in the end the problem had another cause so the treatment didn´t work.
Perhaps a reference to the "Amsler Grid" would be useful as it is something that can easily just be printed out.
|Thread: Steinel SV4 milling machine problem|
A couple more links to the German and (D)english manuals. On the second link scroll down and look for the OneDrive link.
|Thread: Christmas gift for grandson|
Going to **LINK** and searching "steam plant" would point to about 1993.
|Thread: mitutoyo digimatic micrometer 2293-766-10 instructions|
It´s "über" not uber. Sorry couldn´t resist.
|Thread: DRO Operating manual|
I sent you a personal e-mail, login and see.
|Thread: Etching Aluminium|
This might be a bit of an aside but an old way of cleaning silver is to put a bit of aluminium foil in a brine (common salt) solution and then put a tarnished bit of silver in. It works, you can smell the hydrogen sulphide from the tarnish being removed. Afterwards the aluminium foil is pin holed, possibly selectively etched by the process. Perhaps an electrolytic process might be worth trying though the pH might change during the etch.
|Thread: 'What LatheXXXXX sorry 3D Printer should I buy'|
Thanks for that. Still drooling over Prusa offers.. Can you clean the nozzles by torching them the way you would clean an injection moulding screw? (as long as the polymer concerned isn´t PES)
I like this thread on 3D printing and am inclined to buy the hardware. Sorry to be pedantic, but at some stage I ask myself as to when the effects of viscoelescticity/melt expansion and crystallinity/annealing will manifest themselves in 3D printing (i.e. in the dimensions, stress and strength of the part. In injection moulding there is a lot in the meltflow and how it freezes off. Stuff a melt through a nozzle, it expands afterwards. Anneal a casting and mess with the crystallinity and it will distort. How do you take these effects into consideration? In particular the crystalline morphology should affect the strength of the part unless it is just used as a form in a lost wax moulding process or as an ornament.
I had a bit of a crash course in these considerations in thermoplastic composites.
|Thread: Silver Steel|
How much relief does a cutter actually need if cutting brass?
Thanks for the suggestions and the illustrated guides. I´ll try the eccentric approach. I was a bit wary of using this approach with my small lathe. I´m trying to make a 0.6 mod cycloidal cutter so the cutting tool is small.
As to the silver steel, it machined okay, just the piercing saw blades I have seemed not to take kindly to it.
A long time ago I bought John Wilding´s book on how to make a Weight Driven 8 Day Clock. In discussing gear cutting he describes a gear cutter. I tried to make such a disc type profile cutter. You create the edge profile, introduce radial slots and then saw parallel to the circumference to create a lot which is then collapsed by walloping it one. You can try to get away without the relief or using his idea you slot the disc and you cut a slot (with a piercing saw) parallel to circumference for a part of the tooth and wallop it with a brass object to create relief on the cutter by collapsing the circumference partly into the space left by the slot..
I thought I would try it.
Piercing saws and silver steel don´t get on. Is silver steel delivered in some highly annealed state? Sometimes the steel cuts, sometimes not, either it is work hardened or just delivered that way.
Any insights please?
|Thread: PEEK plastic for sliding steam valve|
There aren´t too many producers of PEEK, its high processing temperature makes it expensive to compound and extrude. The base polymer is also expensive.
Igus seem to offer preformed liners. The trouble with machining a sleeve from rod is that you throw most of it away, okay for prototyping but you would extrude/injection mould it if you scale up. . You will also need a bit of practice to see how it machines.
Drake in the US **LINK** seem to equate 450FC30 with the Solvay Ketaspire KT820SL30 (but see the caveat at the bottom of the page).
Try Victrex tech service (Fleetwood/Thornton Cleveleys in the UK), they might know who supplies small quantities in the UK or around Europe.
Have a look at Solvay´s site for Ketaspire
**LINK** and download the processing and design guide. Look out for KT880-SL30 or FW30. The mechanicals don´t match exactly.
Or look at Victrex´s website **LINK** and look at PEEK FC30.
Both have some simple temperature data (tensiles etc.).
From the density and mechanicals you are probably looking at a higher melt viscosity PEEK grade with about 30% carbon fibre, some graphite and PTFE in it (+ some other non-reinforcing filler eg. mica to lower the mechanicals a bit more).
The crucial temperature is the glass transition temperature of PEEK at 143°C.
|Thread: Help with clock escapement|
Did you see these threads on the NAWCC? Some nice pictures.
You don´t seem to be the only one having fun with this escapement.
|Thread: John Wilding 8 day Weight Driven Wall Clock|
Reducto ad absurdum. If the spring is too stiff the resonant frequency depends on the spring not the length of the pendulum. The suspension spring should just store enough energy to keep it going, if too stiff it will kill the oscillation, the movement of the escape wheel will be countered by the stiffness of the spring it will not disengage. Too stiff and you can fiddle with the length of the pendulum as much as you like, you can never adjust it to keep time, the spring dominates gravity as a restoring force. Both books say 0.006" for the thickness, as far as I can tell mine is running with a 0.004" (0.1mm) spring, I tried 0.006" but had problems (perhaps for other reasons). In any case depending on the heat treatment of a steel the modulus should vary anyway. Regards, Dick.
Hi Jim, I don´t know how you have the movement mounted but you need to check that is in beat. You need a scale behind the pendulum rod, low down, so you can judge whether the tick and the tock are symmetrical about the neutral (i.e. vertical position). The movable collet that fastens the crutch to the arbour with the anchor / pallets on it. If the collet is not too tight you can hold the anchor with two fingers and move the crutch relative to the entrance and exit pallets. The adjustment is tiny. Listen to the tick whilst moving the pendulum slowly by hand. The kick from the escape wheel keeps the pendulum going. If you have a light clock oil, put a smidgen on the pallets. the clock has a eccentric on the pallet arbour to change the amount that the pallets engage the escape wheel. Turn it a fraction clockwise and it engages a bit more and you get a bit more kick, too much and it stops. What are you using for a suspension spring (thickness) etc.? Try a little bit more weight, once it starts to go it´s a bit like running a car in (nobody does it anymore) you are probably going to take it apart again anyway to clean it once you get it going. Regards, Dick.
PS. Based on my cousin´s experiences with her grandfather clock, cat hair is lethal to the smooth running of a clock
Jim C:- Before you start cutting metal, try the weight you have´, without the pulley and add some weight e.g. with a bottle of water/sand (a bit of thick wire should do to suspend it, make sure it doesn't turn and interfere with the pendulum) tagged on below your weight. By my calculations your weight is pretty much 2Kg. A drop of oil, even on the pallets? You can vary the depthing of the escapement with the eccentric at the front, start with it in the neutral position and turn slightly clockwise to make the pallets engage more. Move the pendulum by hand and listen for the tick and tock, they should be symmetric about the vertical neutral position. The clock has an adjustable crutch, i.e. you don´t have to bend the crutch to get it into beat. You can alter the position of the crutch relative to the escape wheel arbour. Conversely make sure that the tightening screw that holds the crutch in place is tight (given the moment on it, if it is slightly loose it can lead to strange effects, been there, done that)!
Once it starts to run, leave it alone for a while, go have a beer or whatever. Try and see how long it goes for.
Alan:- Sorry to hear of your frustration. Having taken the blasted thing apart many times to look for faults and one time even managing to put the anchor in the wrong way round I know how it can be. I messed about filing down the anchor pallets until there was nothing left and then made a second.
I´ve got lots of other peoples clocks going over the years but when it came to my own....
Depending how you read the books the answer is different.
Without the weight pulley the answer is about 2.2 Kg, if you have the pulley in and hence half the drop and energy the answer can be more than double this. The second book (at least) has a second roller to try and counteract the effect that the cord wrapped round the barrel wanders back and forth, this roller seems also to add a bit of resistance/friction. The ideas that the clock should rattle and a bit of oil should be present are also good. If this doesn´t work go looking for rough teeth on wheels and pinions. At the beginning it even made a difference whether I hung the other end of the cord to the left of the pulley or to the right. Left, ( viewed from the front) worked best. At one stage I found I had put the thing together so tightly that with the screws on the pillars tightened, I could stop the thing by gently squeezing the plates together with my fingers. It should rattle! If in doubt test each arbour individually. I don´t think my clock is a particularly good example but it runs. Now how about a case for it? Hope this is helpful.
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