Here is a list of all the postings John McNamara has made in our forums. Click on a thread name to jump to the thread.
Thread: Drill table Clamp Vice and a treat for train buffs. |
25/06/2022 08:57:10 |
Hi All |
Thread: I may be stupid but |
24/06/2022 00:49:53 |
The scroll in a 3 jaw chuck has to have a small amount of lateral clearance within the chuck body or it would seize up. this creates a small and unavoidable radial error that grows as the chuck gets older. Edited By John McNamara on 24/06/2022 00:51:06 |
Thread: Seamus |
13/06/2022 15:12:21 |
Greetings From Melbourne Seamus. |
Thread: 3D-CAD Package Shootout - Cotton Reel Example |
01/05/2022 02:17:51 |
Hi All |
16/04/2022 09:51:11 |
Thought I would add some cotton just for fun |
Thread: Best Budget 3D Cad software |
15/04/2022 04:47:55 |
FreeCad Cad Cam (Completely open source.) The presenter at the JOKO Engineering You tube channel has made many other videos on FreeCad**LINK** |
Thread: 3D-CAD Package Shootout - Cotton Reel Example |
13/04/2022 16:45:12 |
Cotton reel drawn with plain Autocad |
Thread: MEW, ME, RCM&E and Model Boats under new ownership. |
05/04/2022 04:37:19 |
Hi All A spring clean in the UK with a new broom, maybe a good thing, Model engineering or as I prefer to call it DIY Home shop machining is changing. Like it or not Automation is coming. While there will always be traditional hand guided precision toolmaker level machine work. CNC Automation is here to stay. Tn this case the duck needs to survive just like the magazines. Change is a good thing if it is balanced. Regards PS: |
Thread: An unpleasant nocturnal experience. |
11/01/2022 07:13:47 |
When we moved into our house about 45 years ago it was derelict, a brick Victorian with bad everything except the cracked walls. ! Yes it even had a council notice served on it. that it could not be re-let, The previous owners were terrible, the worst kind of landlord. Anyway for a youngish couple like us then it offered opportunity, and years of work restoring it. There was a lean-too at the back that was in slightly better than the front, at least there were no holes in the floor. It was here we slept for the next couple of years. however when we moved in there were another occupants, In the roof there were possums. About the size of a medium size house cat these critters like the protection of the roof space. I gather they have an appetite for certain physical endeavours, All know is they make a lot of noise when engaged. In due course I was able to close of the holes they used and we had a little peace. But then there was the scratching and scurrying noises with the occasional squeak. A rodent! Anyway one night I could hear him in the next room It was actually a walk in cupboard about 1.8m square. I knew with the door closed there was no exit. So in I went and closed the door. I was armed with a broom. And so the battle started. I had no Idea how fast a rat can move. and yes they really are aggressive when cornered! Fair enough too I was on his turf and he was defending it. Sadly a story like this has to conclude with an outcome and yes after maybe 15 minutes of me shifting boxes and Mr Rat darting and lunging, the broom minus the head which had broken off settled the argument. I was never happy about that argument, I guess you do what you have to do is the right rebuttal. Having now moved to the country I See rats and mice in the fields from time to time. I wonder if they know I am a killer? Our country garden is also home to many Antechinus a pouched Marsupial About the size of a large Mouse. Most times I go for a walk I will see one. The live on insects mainly. The Males have a very short but happy life, a few weeks, adding to the gnome! Cities within cities within cities. |
Thread: WIN-10 Query |
13/12/2021 12:28:08 |
Hmmm Windows 10. Overall It works well in an evermore Microsoft centric sort of way, you can turn off all the back to base stuff it asks you about when you install it hoverer it periodically nags and nags asking you to turn on this or that "Feature". I did an update from Windows 7 to 10. not a new installation. It installed my licensed Non Subscription version of AutoCad 2021, Revit and 3D Studio and two versions back. However previously installed earlier versions did not work. Yes this is in accordance with Auto desk's licencing policy, however they all worked with windows 7! This may be a problem for other users with older versions. I guess it calls home while Transferring. I still use Microsoft Office Pro version 2003. including MS Access That transferred successfully. However hardware gremlins that have caused me a lot of grief. I have an HP 42" Designjet 500 plotter and a Xerox Office printer. Both are connected to a separate Windows 7 PC that is connected to the network. I can print a pdf created in Autocad if i transfer the files to the PC then print it from there The same applies to Microsoft Office Word Excel and Access programs. I can also print to both printers over the network from another windows 7 PC. But not windows 10. Anyone with older hardware should check, they may need to keep an older Windows 7 PC to run it. Regards |
Thread: Is installing skylight expensive? |
11/12/2021 06:21:03 |
I have specified dozens of skylights. Recently I have been involved in construction. I have always used Velux, some types open some are fixed, manual or automatic. In my view blinds are essential to keep out summer heat, Velux supplied blind kits are likely to be half the cost of having a local blind company make one to fit a skylight. Depending on the area insect screen as well if they open. Take note that the roof angle has to be considered, not all types will not work with with all angles. check the angle first. Cutting the opening to fit a skylight is easy, Velux supply flashing kits for most roof types. The local Velux sales office should have a list of installers. for DIY You can download very detailed installation instructions. Light? Don't over specify check how much you actually need. Beware of creating a heated greenhouse! I have no connection with the Velux company. Edited By John McNamara on 11/12/2021 06:21:58 |
Thread: Antikythera Mechanism |
23/11/2021 10:24:43 |
Good find Michael G From the first Scientific American link you posted. Maybe there is a better copy of this image available? Regards |
Thread: 80th birthday |
20/11/2021 05:54:06 |
Hmm Maybe oysters... But then again, maybe not.
|
Thread: Help in identifying antique milling machine. |
17/11/2021 22:17:56 |
Both Browne & Sharpe and Pratt and Whitney made similar machines. Many companies made similar machines An assembled photo might help identify it. |
Thread: Antikythera Mechanism |
16/11/2021 13:38:56 |
Hi Drewt The centre of the hole(s) arc was positioned by eye as seen below. I tried to visually pick the visual average centre of all the holes. The circles around the holes were also positioned by eye, prior to placing the arc. Reviewing the placement used it looks about right, Improving it would not significantly affect the placement of the arcs. and the the all important radius that assists us in calculating the number of holes. For me that only leaves distortion, the centres should align a lot more accurately. was this distortion physical? The result of unknown forces over time? Or could it be possible that the X-ray scanning methods introduced error. I know the imaging was done in slices, were they truly planar to the mechanism? Could there be some form of spherical distortion of the scanning beam? I would really like to know more about the scanning method. what was the accuracy and linearity obtained particularly over the entire area of the objects. The fine detail is good but that is not all we need. Edited By John McNamara on 16/11/2021 13:42:14 Edited By John McNamara on 16/11/2021 13:43:29 |
Thread: Solid Edge - Community Edition |
16/11/2021 11:43:30 |
Hi Nealeb The link below may possibly interest you? Developed by Art Art Fenerty and Bob Landry, Who created Mach 3 CNC. I have no connection with the company apart from having bought my copy maybe ten years ago and updating it as new versions come along. What I can say is it works well. a bargain if you have a use for it. |
Thread: DIY Epoxy Frame based CNC MILL |
15/11/2021 02:15:37 |
Hi All When I started this project I had no idea that having got so close to a finish, Life pressures would push it into the background. Clearly I have a debt to repay the interest received with a completed project. My workshop is now moved to a new temporary brick garage and hopefully soon I will have 3 phase power. I need the lathe to make some of the parts. I want to build a new shed later this year. But at least I can work in the temporary garage. It will be interesting to see if there is any change in the alignment of the mill, having travelled on a truck about 60 kilometers crane on, crane off etc. The columns and crossmember are only bolted, as noted in the post they were to be set in epoxy then bolted to final alignment. |
Thread: Antikythera Mechanism |
13/11/2021 08:20:52 |
Hi All Thank you Drewt for the image, I am not exactly sure who to acknowledge regarding its copyright. However I wish to acknowledge that it is. How many holes? So far the tests have suggested a lower number certainly not 365 is the most likely? |
Thread: A very close call with a scammer |
13/11/2021 00:17:16 |
Firstly I never repost but this is an important lesson. apologies. Just because it looks all right? You better look very very very carefully. We recently bought a new house. An exciting time. The usual thing we paid a nominal deposit on the day pending payment of the full amount a couple of days later. Having looked at a number of properties with the same estate agent we knew several of the sales staff and the name of the sales office accountant who had properly handled the initial deposit. A couple of days later we received an email telling us the bank account details for the rest of the deposit, The email used the logo and office details of the agency together with the names of the sales agent and the details of the amount owing. However, there was one difference. the bank account details had changed to a new account number. Apart from that it looked like the initial deposit email. Luckily this triggered an alarm in our minds. It was then that we also noticed a difference in the web address, so we phoned the agency to check the validity of the email. They were shocked! They knew nothing of the infiltration of their computer. And yes! it was a scam. I later found out that this bank account number was indeed a genuine Australian bank account number. The Police told me that this is the norm. However, any money paid into that account would have been whisked out of the country in seconds. What had happened is that the estate agent’s office computer system had been hacked. The hackers had gained access to the records of current sales taking place at the time and were able to construct bogus documents to use against current transactions. With all the correct names and logos in place. We were lucky, the small discrepancies triggered that essential check phone call. Had we not done that we would have suffered a substantial loss. As I understand it another client did not notice. and was snared by the scammers net. I don't know if they were compensated. I suspect not. As a consequence, the estate agent shut their offices for several weeks while a new system was put in place. In Australia Property is now settled by computer, not like in the past where the conveyancing Layers for the parties concerned sat around a table. and exchanged documents. Our lawyer who conducted the final settlement told us that many lawyers and other businesses that handle cash had also been hacked in a similar way. She told me that in spite of automation they always telephone other parties verbally and only use account numbers obtained verbally having confirmed that there is no possibility that the party on the other end of the phone is a scammer. The event also triggered a long investigation by our two banks not because we were affected but because they were trying to set up defences to counter this sort of activity, however in my discussions with them I gleaned that as soon as the cash is out of the country it is almost impossible to recover it. Naturally we had put a stop on all our bank accounts immediately, We did not know what sort of information the scammers had. Just because it looks all right? You better look very very very carefully. |
Thread: Antikythera Mechanism |
13/11/2021 00:08:25 |
Hi All Using the second set of observations I made shown in green I calculated 355,83deg. This used the larger fragment with no visible cracking. I guess this larger fragment offers the best approximation accuracy available. The method used was to visually place small circles over the “points” then apply an arc over the circles using eyeball best fit analysis. Can we assume the points were holes? If they are holes I would be very interested to know if the “silt” mentioned previously by Drewt contained iron, particularly at the bottom of the holes? Maybe this would suggest pins protruding that might suggest a pin gear. Getting back to the method. I would like to try it on the best available known image. If available online I would appreciate a link. I will repeat my test using this image. I am somewhat confused by the apparent inaccuracy of some of the points, I firmly believe that a person capable of constructing this mechanism will have been capable of better hole placement. Maybe we should ignore certain outliers from the calculations. Local corrosion might possibly have moved the apparent hole in the substrate. Additionally, there is the possibility of larger (not visible) cracks deforming the substrate. I look forward to a retest on a better image if found. Edited By John McNamara on 13/11/2021 00:09:54 |
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