Member postings for David Cambridge

Which is the great thing about this forum, plenty of helpful people and plenty to learn. Suitable annotation added to video! Thanks Chaps

David

I’ve bought myself a set of slip gauges from ebay, so I’ve been entertaining myself making another YouTube video, using the gauges to measure lathe centre height, and making myself a reference bar for setting QCTP centre height.

David

The wife’s favorite stock pot Tool abuse in her opinion!!!

I’ve a QCTP, and an aluminium bar that if I rest one end on the lathe bed is the correct length for the other end to be centre height. Then it’s just a case of lining up the end of the milling cutter flute with the end of the aluminium bar (bye eye - seemed to work well enough!)

David

Thanks Chaps

The idea of using an end mill as a boring bar worked perfectly!

Thanks all. It sounds like the boring bar is the way to go!

David

I did wonder if that was the case, and it is a while since I checked tailstock alignment. I will do so tomorrow. I haven’t noticed any other problems ,and 0.3 mm error does seem quite bad.

I should add that the part is brass.

David

Hello All

I need to drill a flat bottomed hole 10mm in diameter and 4mm in depth in the end of some bar stock. It will be used to locate a 10 mm outside diameter bearing.

I’ve put my bar stock in a collet chuck (in the lathe), I’ve centre drilled, then drilled to 4mm diameter and 20 mm depth with a twist drill, then drilled to 6mm diameter and 20 mm depth with a twist drill, and then drilled to 10 mm diameter and 4 mm depth with a 2 flute end mill. Unfortunately, I’ve ended up with a 10.35 mm diameter hole.

I’ve no idea why, can anyone offer any guidance ?

Thanks

David

I had a lot of fun in 2016 learning to cast. I started using kit I bought off the shelf , and finished by building my own propane furnace. It didn’t cost very much at all to cast brass with off the shelf equipment (a Sievert blow torch, fire bricks, and crucilbe). You can see how I did it in this video.

It cost a little bit more to build a small furnace and my own burner, but it also let me cast larger items:

Take a look at the rest of my YouTube channel where I have documented pretty much the entire learning and building process.

Once thing to be aware of when casting brass is the fumes are dangerous. Google ‘Metal Fume Fever to find out more’. Just make sure you understand the problem and what you are going to do about it.

David

'Hydrogen and Oxygen in an exact 2:1 ratio ... 'keep away from naked flame'...'

At the risk of being a pedant, it’s hydrogen and chlorine – so keep away from naked flames and naked lungs (if you want to use them afterwards ).

David

Have you considered electrolysis ? I’ve been meaning to try it with salt and electricity, but I still need to do a bit of research before I try it (just in case it yields anything nasty!)

David

A Christmas Clickspring gyroscope build.

David

Having an idle moment, a bit of curiosity, and the need to face a titanium bar I thought I’d answer the question with regards to the possibility of doing this in a hobby lathe. As you will see from the end of the video, the fire risk is certainly none trivial. This was a controlled experiment, but if you are considering doing it yourself I’d certainly recommend watching this first.

David

I’m asking this question from a perspective of total ignorance.

I’ve been enjoying the excellent Clickspring videos and I quite fancy having a go at making his gyroscope. He uses a ‘super glue’ chuck to temporarily glue the gyroscope wheel to an aluminium plate held in the lathe chuck. It might be OK to do this (?), but I can’t help but worry that the spinning\cutting forces on a 0.3 kg mass held only with glue seems a bit dodgy? Does anyone have any thoughts ?

Obviously facing a small clock gear isn’t going to go that badly wrong, but a gyro wheel does have quite a bit more momentum to hit you with if it comes loose.

David

Edited By David Cambridge on 30/11/2016 13:00:30

Thanks everyone. I do enjoy making the videos, and you never know they may be helpful to someone else.

I think I was lucky, and the wheel seemed pretty well balanced without having to do anything.

David

Video updated to include machining the flywheel!

David

I’d not intended to produce any more casting videos, but I’ve had such a hard time getting this to work it might be helpful for anyone else trying the same.

I’m part way through a Wyvern build, and this video is all about the mould arrangement for the flywheels.

David

Hello All

I’m about 20% of the way into a Wyvern build. I’ve got the two gear blanks from Hemingway but I’m a bit stuck. The gear blanks have the teeth already cut, but as they are so small I’m not sure how to hold them to machine them to the dimensions shown.

They were quite expensive so I’d be grateful for some hints before I mess them up! They need to be bored inside and turned on the outside.

David

I see. Thanks Jason – it looks like you went to a bit of trouble drawing that for me. It’s really appreciated.

David

Admittedly re-awaking an old thread, but I have the same question as Terence. It looks like ‘Engine Builder’ has supplied the solution, but I don’t understand what is being suggested. I’d be grateful if someone can explain again.

i.e. I don’t understand:

‘I use a similar system to fit the flywheels to my engines but drill through the collet and into the crankshaft a bit and fit a silver steel pin. Then when you want to take of the flywheel the collet stays on the crankshaft. The pin is drilled and tapped so a screw may be fitted to remove it. The taper is a good idea fitting a key to a parallel shaft often makes for a wobbly flywheel.’

David