Gears and Covid Part 3.... And some other bits.

The 2nd shaft gear was finally complete after quite a few passes round all 69 teeth. Here its shown with a quick coat of red oxide to protect the inner surface. Only remains the mating gear which is slightly bigger in diameter to be started.  

The main reason for finishing one of the large gears was to progress the drilling of the horn-plates for the shaft tubes. I wanted to be sure of the dimension for the hole centres using my gears rather than trying to modify it later.

It appears to be ok but I think I will still make a location spigot for the large gear, fitted into a smaller hole in the horn-plate for a test, so that the hole can be made larger  (and ) / or offset if needed after.     

The Next easy job will be the bolts required to hold the bearing housing onto the plate followed by some holes used for some threaded hex rod in the positions of the back head bolts.

I will then end up with a box similar to what I started with with my first engine. (See below) Only 3 times bigger !!

I'm not sure why I really decided to start another one I think Covid 19 was to blame !!

Minnie Traction engine 29/06/07 15 Years ago !!->

The one above will be some time until it looks like the one to the right but that is the plan for this year. Reduce the shaft tubes to the correct boiler width as confirmed from 2 boiler makers as the finished size of the fire box is 6 - 1/8",  the fire box is 6" the stays are 1/16" each side.

In other news the welder I have been messing with seems to work! 

I have sorted out the Co2 gas regulator (ebay £9.99 SH) and after some practising I should hopefully be able to make gear guards, tender sides etc. 

As my son is a welder he had first go and the results were very good, not on par with what he is use to from the TIG set at work, but up to the job for what I need. 

The first real job for this is going to be making a box section frame for cutting key ways using a hydraulic car jack and broach. Essentially like a harbour press but home made and potentially designed to be able to take it to pieces when no longer required. 

Last item for mentioning I have decided to make a simple gear depthing tool. 

This was described in the Minnie Constriction book as a simple way of setting the gear mesh clearance. As this worked well on the other engine, I decided to make a bigger version of the same tool at a fixed distance of 122mm with the option of making one end a small slot for adjustment.

This is instead of drilling the horn plates, as by way for a test, then using this flat bar as the drilling guide. Photo to follow when it has been completed.

It was found that even after an amount of deburring and checking that the mesh became tight in a couple of spots when the gears are rotated, and it may be that I need to cut the teeth a little bit deeper but only by a small amount (say 0.004"). I haven't made a final decision on this yet as it carries a risk in getting the gear set back up on the miller.   

 I got covid so progress has all but stopped for a while until I'm back fully fit!!!