Member postings for mick

Does anyone know where to get hold of a small radial control carburetor suitable for a model aero engine, ideally from a UK supplier, but if needs be, from overseas.

Thanks.

Most industrial dividing heads have a bayonet fitting that allows the sprung loaded location to be held clear of the indexing plates while rotating the crank handle, sadly not included on small hobby versions.

A pattern makers ruler is 13'' long to allow for shrinkage, which doesn't have a thing to do with this post, but just thought I'd lob in it!

The ERIKS "O" ring calculator is very good, just select material, size etc and it does the rest, an online search for Eriks O rings, should bring it up

I feel it might be easier to machine the 60deg groove parallel along the length and then machine the taper on the top face of the block.

Hi Jason.

How can you work out the angle without knowing the length?

A taper mandrel has a 0.003'' taper over its entire length. 0.001'' under at one end and 0.001'' over at the other. you probably won't even need to set the compound slide off the zero mark to achieve it.

Every step you take is the unavoidable consequence of the proceeding one and there beckons more, clearly total annihilation.

Albert Einstein.

Not trying to be clever, just another way of looking at the use of tools. Mick (still breathing)

Smooth off one face and sell them on Ebay in sets of five as "shove pennies"

I'm making a multi cylinder four stroke IC petrol engine, the bores are one inch diameter and the stroke is an inch and an eight, I've no real idea of the RPM, but for this purpose lets say 4000. If anyone can work it out the temperature inside the combustion chambers from this scrap of information, I would be grateful. I've seen various examples online, which range from 100c to 350c. I intend to try and bond the stainless steel valve seats into the Ali head, rather than using the interference fit recommended, as there's seems to be a chemical bonding agent to cover most industrial applications these days, so I would need to select a bonding agent that's recommended to be efficient at temperatures in excess to those in the combustion chambers.

Thanks.

Hi. John.

Took out the G44 & G49 and it seems to work on the graphic screen, I'll try a dry run on the machine when I reach a suitable stage in a couple of days, its a starting point anyway. Thanks.

Thanks John, I'll try altering the values and see how I get on.

Maybe this might help

I not making myself clear. the arc centre is at Z-36.5 the arc itself would start some where around the Z-3/4 mark at X10.3 then a gentle sweep to X0 then on to X-10.3

Being an old school G code programer I've never embraced CAD/CAM but wouldn't be without the conversational programing my control offers. I now need to machine an upstanding arc, with its centre at Z-36.5 the arc starts at X10.3 and finishes at X-10.3 (there is no Y motion involved) Having had a look at the manual G18 would appear to be prefix before G02/3 with the arc values signed by I & K. I've tried different combinations on the graphics but nothing runs. Can anybody supply a template for a ramping arc, (that runs) where I can fill in the values.

Thanks

JB Weld would be my first choice, it takes six hours to even start curing, but after 24 it should be completely set, I'm sure you'll be surprised by the results you can get with this bonding.

If that's the tool your using, then throw it away and try a "V" shaped tool with a good positive radius top rake, the rake in the photo is almost negative, which gives the swarf curl no where to go. Tools should be razor sharp with the tip stoned or lapped with a diamond hone. The chips should be lifted away from the parent material, I think the tool your using would tend to gouge the metal away as the tool is fighting against the mechanical forces. Start with slow ram strokes and table feed and build on these when the tool and surface finish are improved. At the first sign of vibration, stop, adjust the depth of cut, stroke and feed rates

If my machines could talk, I'd probably pay them to keep quiet!

Perhaps you ought wait till Friday when its open!!

Once the tool has started to vibrate and cause chatter then getting rid of it especially in a groove by machining is a bit tricky. In the past I've achieved a passable result by turning the chuck by hand, or with the chuck key, against the tool, obviously only very small cuts of 0.001'' or so can be taken, but with a razor sharp tool and a little cutting oil you should be able to improve the situation.