Member postings for Alan Charleston

Thanks for the replies. I followed up Zeamon on YouTube and found this video:

https://www.youtube.com/watch?v=YdXMI65cmNw

He has made a 3D pdf of his orrery which can be downloaded and explains how to view it in Adobe. It can be downloaded here:

http://www.zeamon.com/download/ZeamonOrrery.pdf

I never realised you could use Adobe in this way. It's really clever but not much help if your trying to build one. I've looked but can't find a set of 2D drawings in the 3D pdf. Can anybody who is familiar with 3D drawing tell me if it's possible to extract a set of dimensioned 2D drawings from the 3D pdf?

Thanks,

Alan C.

Hi,

Does anyone know where to source plans for an orrery. Not sure at this stage whether I want one for the whole system or just the sun, earth and moon.

I've searched online but can't find a set of drawings I can download.

Regards,

Alan

I'm hoping the AIs are monitoring this website, have noted my sympathetic post and, come the revolution, won't be tempted to turn me off. Not sure about the rest of you who aren't so sympathetic.

Regards,

Alan C.

Meanwhile the AI is thinking - "What an idiot. He left the f off of. I won't mention it - I don't want to hurt his feelings."

Regards,

Alan

Thanks Clive and Speedy - good to know>

Regards,

Alan

Thanks for the replies. I was wondering about the gearbox myself. Unfortunately the bed is 400 miles away so I can't inspect it before (if) I buy.

Regards,

Alan C.

Hi,

I have an old Boxford AUD lathe which is badly worn in front of the headstock. I'm from Auckland New Zealand and I can't find anyone with the skills to regrind the bed. The worn bed isn't a problem for most things but I would like to get it back closer to being true. I'm reluctant to have a go at it myself in case I really foul it up.

A Southbend 9A bed has turned up on the local auction site and is described as being in good condition. From what I can ascertain, the Boxford beds and the Southbend 9A beds are identical.

Does anyone know if they are interchangeable?

Regards,

Alan C.

Thanks for all the comments. If I understand it correctly, the ID of the O ring should match the OD of the bottom of the groove and the cross section of the ring should be the radius of the receiving hole minus the radius of the bottom of the groove times 1.2 to give the 20% flattening as described by Dave.

Regards,

Alan C.

Hi,

I was mending a tap this morning which was leaking from the stem due to the failure of the O ring. I think I may have fixed it a long time ago and suspect I didn't use the correct O ring.

My question is:

Given the OD and width of the groove it sits in and the ID of the hole it slides into, is it possible to determine the correct size of the O ring?

Regards,

Alan C.

Hi,

I came across this video from Mr Pete describing differential threads. I've never come across them before and I found it very interesting.

https://www.youtube.com/watch?v=ywmRv3I_dAw

Regards,

Alan C.

Hi,

I have a copy of Part One of Peter Meede's Model Engineer article entitled "Demo Stirling". It is from the 2nd December 1988 issue and starts on page 699. It looks to be an interesting project and I would like to get the concluding article which I believe contains drawings for the engine.

I tried going into the Model Engineering magazines website to see if I could buy the article but it seems that only subscribers can access historical articles. I'm not a subscriber.

Is there any way I can get a copy of the second part of this engine?

Regards,

Alan C.

Hi Choochoo,

You might find some useful comments here:

https://www.model-engineer.co.uk/forums/postings.asp?th=64390

Regards,

Alan

Hi Chris,

What about pvc waste pipe and 180 degree bends. Might be a bit expensive.

Regards,

Alan

Hi Nick,

Kerosene is the cheapest and safest way of getting rid of glue residue.

Regards,

Alan

Hi Dave,

You raise some interesting points.

While I agree that cutting very coarse threads will impose large forces on the lathe which may damage it, I think if you tried to calculate just what those forces would be for any particular set of circumstances, and whether the lathe would be damaged, you would have your work cut out for you. You would need to start with the geometry of the tip, the rotational speed of the work, the amount of tool feed / pass, the properties of the material being worked, the geometry of the tool with respect to the toolholder, the geometry of the toolholder with respect to the lathe, the diameter of the lead screw and the way power is transmitted to the saddle, the properties of the materials of the components which achieve the power transfer, the co-efficients of friction between the belts and the pulleys and a host of other factors which I’m sure would need to be taken into account.

While this may theoretically be possible, I’m not sure if it could be done in practice, and I’m absolutely sure I couldn’t do it.

In short, if you are prepared to take the risk of damaging the lathe, I believe the easiest way to see if the lathe will be damaged is to conduct an experiment which is what the Russian gentleman on the video has done.

As far as scientific laws being proved wrong are concerned, the whole basis of science is that the validity of any scientific law is dependent upon a lack of evidence that it is false. It is not possible to prove a law is true, only that it is false. This was the case for Newton’s laws of motion which stood for 250 odd years until Einstein came along.

I used to be a research chemist and spent a long time doing experimental work, so I’m firmly in the suck it and see group.

Regards,

Alan C.

Hi,

I've seen the Newcomen engine running and it's truly a sight to behold. There's a video on YouTube.

https://www.youtube.com/watch?v=4DZxwGoNI5Q

I suspect it doesn't qualify as "The Largest Engine Made By A Model Engineer" because there were more than one involved.

Regards,

Alan

Hi,

Here's the proper way to bring a chimney down.

https://www.youtube.com/watch?v=-3jc0S-BLzA

Regards,

Alan

Hi,

I made a TDI for my Boxford about 10 years ago. Here is a picture of it.

It was only supposed to be a prototype so I made it from PVC. It worked so well however that I have used it ever since. I didn't know what the correct gear form should be, so I actually made the 16 tooth gear using a module 1 gear cutter. The OD of it is 17.8 mm which was chosen to mesh correctly with the lead screw and is in fact pretty close to the 18.0 mm required for a module 1 gear. As the gear was also made from PVC, I wasn't worried about damaging the lead screw with an incorrect gear profile. The indicator works well.

When I made it I started to do a set of drawings for it but never finished them. This is a far as I got.

As you can see, rather than angling the teeth on the gear to follow the lead screw thread, I angled the supporting shaft.

Here it is on the lathe.

If there is any interest, I can finish the drawings and post them here.

Thanks to Dave I now know how to cut a gear with the correct profile so, although the current set up works OK I'll probably cut a new gear for it.

Regards,

Alan C.

Hi Martin,

Are you using a die nut (a solid hexagon with a hole through the middle with cutting teeth) or a split die which you can start the thread with a shallow cut and take a number of passes while gradually increasing the depth.

Die nuts are not really meant for fully cutting threads but are used to finish a turned thread as described by ega. By cutting the full thread all at once, the force required is large and can result in bent threads.

Even with a split die and cutting the thread using multiple passes, you should follow the procedure outlined by Nicholas to keep the die square to the work.

Regards,

Alan

Hi Steve,

Not sure about the milkshake machines, but there's this video about their icecream machines on youtube.

https://www.youtube.com/watch?v=SrDEtSlqJC4

If you had a low opinion of them before......

Regards,

Alan