Member postings for GoCreate

I think it's a statement made with respect to hobby machines, industrial sized machines are rather over kill in a model engineering context, for the vast majority at least.

My Worco 12x 24 lathe and VMC mill have good capacity and would be considered large capacity machines so much so I do also have a Sherline lathe and mill for tiny work. In a model engineering context these are the 2 extremes.

Nigel

Edited By tractionengine42 on 05/12/2014 08:56:53

Hi Stephen

I have an interest in Rotary and Radial engines, after reading your very interesting article in ME I was hoping to here more news of progress and here we have it. Very glad to here your model is now running, unfortunately the MEX exhibition to far for me as I am in Aberdeenshire, I would love to see it in the flesh. Be good if you could make the Harrogate show in 2015.

I will be looking for a new project next summer, I think this radial may be a timely contender, I do prefer the larger scale and there looks to be some interesting machining challenges.

Beautiful model, very well done indeed.

Nigel

I have been thinking about tig,  a friend of mine uses sil-bronze for welding/brazing motor cycle frames.

Here is tig brazing steel to st st.

Nigel

Edited By tractionengine42 on 20/11/2014 23:21:08

Edited By tractionengine42 on 20/11/2014 23:23:29

As indicated by Robbo, it's a deliberate feature to prevent damage should the operator allow the table to move past the end of it's stroke on power feed. I frequently set the auto feed on my Elliott and walk away to do something else, a couple of times I have not returned in time before the table reached the end of its stroke, this feature prevented damage to the feed screw etc. it's a good feature to have and keep.

Nigel

Bert, have a look in your control panel - programs and look down the list for any unexpected programs.

I found 2 programs had been installed without my knowledge, one was called something like "shopad", after un-installing the programs this problem disappeared.

Nigel

I found these 2 books very good for a complete beginner. I would recommend Getting Started with Sketches as a first buy. These combined with an Arduino starter kit got me going.

Getting started with sketches

Adruino workshop

Nigel

Aduino uses: -

Could an Arduno board be used to synchronise a mill spindle (with encoder) with a stepper driven rotary table/head to allow gear hobbling on the milling machine? I have the CES hobbing machine castings under, maybe here is an opportunity to enhance the machine and eliminate all those gear trains needed?

Convert a hand operated surface grinder to automatic operation using stepper motors, the idea being you can input the X traverse and feed rate + y traverse, feed rate and step over per pass. Maybe OTT for this type of board?

I have no electronics experience but I have had a play with an arduino Uno and found it quit fascinating. I used one for a work project cycling hydraulic cylinders under test. I arranged it so that you input the advance and retract times and the no of cycles required, The arduno interfaces the pump control box via a relay board, it starts the pump, operates the advance/retract solenoid valve for the required no cycles then stops the pump. Via a pressure switch, if the pressure does not increase (probably due to a hose/seal failure) after a few seconds it stops the test. It also monitors the pump temperature and stops the test it exceeds 50degC.+ a few flashing LED's to add interest This was a very good learning exercise and has worked well for the last 6 months.

Nigel

If your model is to be insured and steamed in public, should it not be the case of establishing what design stress, joint factor and safety margins are acceptable to the boiler inspector and insurance company. Then the design can be worked out to meet their requirements and subsequently approved by them. In other words what code of practice do they accept?

Although you have done some testing to justify to yourself the safety of your design these are unlikely to be taken into consideration by your boiler inspector or insurance company unless very well documented and maybe also witnessed.

I am not familiar with the formulas stated above, the following table shows calculated tube thickness using a standard hoop stress formula (also typically used in pressure vessel codes). I have used some values suggested above for yield stress and joint factor and included a range of safety margins for comparison. Normally you would establish a design stress based upon material mechanical properties and operating temperature and use this in the formula.

Other considerations concerning boiler tube thickness will be a) does the boiler tube support any other significant structures like cylinders etc. b) what reinforcement is applied to openings/nozzles.

One method concerning openings/nozzles is to use an 'area replacement method', basically you take a section through the opening/nozzle, calculate the area of material removed then ensure that any reinforcing ring has at least the same section area. If the boiler tube is thicker than theoretical then the extra thickness above theoretical can be included in the calculation, for example, if the theoretical thickness is 0.05" and the actual thickness is 0.15" then there is a good chance that a reinforcing ring is not needed as the actual tube thickness already has sufficient strength. There is a specified method for determining the width of any reinforcing ring, I would have to look this up.

Here's a useful source of information.

I hope this is useful info.

Nigel

There's a explanation of hydrogen embrittlement in copper here, in particular refer to text just above fig 16.

Nigel

Fizzy/Jason

Ye looks like C101 should be avoided as it's not oxygen free, apologies for my bum steer.

There's some comprehensive technical data on that Cup Alloys website, very interesting.

Nigel

Hi Fizzy

C101 is 99.9% pure copper, not absolutely sure if that's what you need but CES do sell it in 16 swg

Nigel

Hi Graham

No desperation at all, please take your time.

I also sent a PM and payment on 5th and have not received any PM or confirmation.

No worries.

Nigel

Hi Nanande

15.5mm will probably be the nearest standard metric drill available.

Drilling 15.5mm the reaming 16mm will be perfectly OK. Less than 15.5 mm will not be desirable.

Where possible I prefer to bore the hole before reaming, I would drill 15mm, bore to 15.7mm them ream 16mm using cutting fluid when reaming steel.

Nigel

Originally I painted my concrete floor with industrial floor paint, after a few years the paint was very worn and concrete dust was becoming a problem.

I sealed all the worn areas and covered the entire floor with these interlocking tiles, I have found these very durable and comfortable, in my view worth the effort and money.

Nigel

Andrew

I think maybe Neil is referring to feeding across the work face manually, not on auto feed. So if you increase the rpm you have to turn the feed screw faster to maintain the feed rate in thou's/rev.

Nigel

Hi Graham

I am waiting patiently, no hurry. Very much appreciate your time and effort, this is very generous of you.

Nigel

Neil

Jason is referring to Model Engineer magazine, not Model Engineers Workshop.

Nigel

Thanks Jason

That makes sense now and useful to know.

The article needs a revision.

Nigel

I was reading through Practical Engineer part 1 article on this forum  regarding cutting speeds but I am a bit confused.

The article states:

1" x 375 = 375 RPM for steel

1/2" x 375 = 188 RPM for steel

1/8" x 375 = 47 RPM for steel

What am I missing?

Nigel

Edited By tractionengine42 on 10/08/2014 07:16:13

Hi

Very interesting hat posts, It's amazing the very diverse things you can learn on this forum.

I've only ever worn a woolly pompom hat. Soon I hope to be steaming my 3" scale Allchin traction engine, so that may be time for a suitable hat or cap.

The 1-1/2" scale drawing show a dummy displacement lubricator, for my 3" scale I decided to make a working version. Finished it over the weekend, here's the parts and the finished item fitted to the engine. Turned out quite well I think.

Nigel