Member postings for Pat

Hi Andy - Never ever raise any oil to boiling point as this is a fire hazard as the fumes given off will be above the liquid oils flash point. I only posted the oil method of drawing the hardness down as this does not need any special equipment other than a suitable source of heat and a container. Olive oil and many others edible oils smell very good where as mineral oil is not good and is probably poisonous.

The domestic oven is ok but in my experience the temperature need to be watched all the time as the oven themostats are not precise so the temperature wanders up and down quite a bit. I use an industrial glass / mercuary thermometer that is in a protective steel tube. The oils are from the supermarket or the local deli.

Regards - Pat

Hi Andy There are alternatives to salt for the lower teperature tempering of previouly hardened parts . For example for light straw simply use olive oil. It starts gently smoking at 190C to 200C and the smell is OK but there is a fire risk if heated to its boiling point arround 300C. Other oils can be used SAE30 oil could also be used but the fumes are not good.

As these oils vary a bit it is advisable to measure the temperature  of the actual oil you have.

Here is a link to some other oils and their smoking temperatures. **LINK**

And here is a better link to kitchen edible oil smoke points

http://en.wikipedia.org/wiki/Corn_oil#cite_note-chef-5

Regards - Pat

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Hi jason

Thanks for that link the digitising probe looks interesting. As I understand the process there is an eletric micro furnace with cruciple included in the kit. The domestic microwave is used to melt the wax from the investment plaster cast and vaporise any remaining wax. The metal is then melted in the supplied electric furnace and poured into the mould. This process is for small parts so should suit some model makers.

Regards - Pat

Seen tools very similar to those in the picture except they had wooden file handles on the short end. They were used to assemble thin aluminium sheet metal parts into a former and to get the reference holes to line up with the reinforcing rings prior to drilling additional holes for riveting. They were called podgers and had similar square sections on the shanks to make removal easier. The full diameter of the slow taper was the diameter of the reference holes and were filled after removal from the former after inspection. The inspectors would be check that the reference holes were correct. This was in the aero space industry in the 70's. Regards - Pat

Hi Chris

These small mills come in a variety of different configurations and there are several factories in Tiwan and China making them. So not only do they come in different colours but they eminate from different places as well and to make the mix even wider some importers have them badged and made to their own specifications. What I am trying to put over is that just because they look similar there can be differences in the castings and the clearances between the moving bits.

Here is a link to a site showing DRO scales fitted toa Seig X2. This mill has a tilting mast but the X and Y axis arrangements would be similar .

**LINK** Amadeal and ArcEuro have the scales but you would have to improvise your own brackets as per the link but the dimensions may be different. You could also search the CNCZone for X1 + DRO

Hope this helps - Regards - Pat

Hi John

I found a suitable Vee belt as a sewing machine spare in a shop that specialises in the repair of domestic sewing machines. I think it was from a Toshiba sewing machine - it is vee section with polturathane covering. All I did was take a bit of paper with the correct diameter circle drawn on it and a bit of card with the correct angle. The belt is very flexible and designed for small diameter driving pulley of similar diameter as used in the design by Hoss. Not sure about the exact profile as I worked from the belt and a pulley from a dead motor. The advantage of a vee belt is that it acts as a clutch of last resort but a HTD toothed belt should also be as silent.

I have not completed mine yet as I want to get the Z axis drive for CNC sorted first. I have in mind moving the motor to the control box side so that the ball screw can drive down the centerline of the rack.

Hope this helps - Pat

And in diagrammatic form belowjust reverse the connecting rods to get the configuration shown.

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