Member postings for AStroud

here are the parts so far on my scratch design long stroke mill engine

Thank you Jason, good advice about machining the crank and pin, I will follow your sequence for my new build and I will take a lot more care with the alignments.

Andrew

Some interesting points made, thanks.

I think Ramon's advice about ensuring parallelism between the crankshaft pin and cross head pin is spot on and is probably the cause of a small knock I have on my Corliss which instinctively makes you think is bearing clearances somewhere but I cannot find any. I need to think of a way to check the alignment with my limited equipment.

Andrew

Thanks.

Yes I am planning to run on air.

Another objective was to build from my existing material stock, so preliminary design is 1" bore x 2 1/4" stroke, a tubular crosshead guide from material left over from the Corliss build and a 7" dia flywheel. I do not have material to fabricate a base frame so it will sit on a 6mm plate, probably on a plinth made from wood. Minimising the gland and piston seals sounds like a good tip but I don't like the sound of constant hissing indicating leaks either so a trade off is needed.

Hi All

Having built a Potty mill engine, a Monitor and an MEM Corliss for my next build I am planning an own design mill engine.

I want it to be slow running and silent. I seem to remember a bore to stroke of 1:2 is good and a connecting rod length of c. 5 x the stroke gives a pleasant motion, is that about right ?

Am I also right in saying as long as the steam ports 'match' the eccentric throw then the steam chest size and dimensions do not really matter as long as the ports are large enough for the estimated air flow ?

I want to eliminate any possible sources of knock, I know that means tight bearing tolerances but any recommendations out there to minimize mechanical noise ?

thanks for any advice Andrew

I thought members may be interested in my completed excavator arm, something I have wanted to build since being a small boy.

I have scaled it from a die cast Kubota model I have and it was never my intention to make a replica model, just somethig that looked OK and I could play with. At the moment I am running it at a 100 psi at which it seems to have more than enough force. During some early experiments I used up to 150 psi and apart from a few tubes blowing off it held together.

My main concern was that the 4mm tubes used would be so restrictive as to make the speed of operation too slow but it is OK and 'to scale'.

Going to get some cat litter so I can have a play.

I think you mean Alan Millyard and yes in the last TV series we saw he has a Bantam (lathe, not bike)

mea culpa, I had measured in situ. I have taken the gear off and remeasured

Good morning

Just measured the 12T on my S7 and the OD over the teeth = 0.723"

I have a Myford Super 7 made early 1960's and bought about 16 years ago. It has had a hard life with nicks and dings on the bed and slides and needs a regrind or converting to the wide guide for the saddle.

Why did I buy it ? I used Myfords in school techl class and so was familiar with it and it was the go to for the hobbyist at the time. It has its well known limitations but OK for the work I do, in fact I select the models I make by checking what I can do on the Myford. I have bought second hand accessories for it as needed. I also have classic bikes and most machining needs for them can be done on the Myford. I often surf to see what is on sale and often I see some beauties available but then ask myself do I really need to change and the answer is no.

Mine came with a 1ph motor fitted (3kw !!). It had been fitted by someone drilling mounting holes in the column about 5 1/2" down from the top mounting holes and I am guessing they must be tapped. Spacers are used to align with the pad. Otherwise I would have thought an adaptor plate would suffice.

Edited By AStroud on 19/12/2020 15:51:05

here's mine, seeing others makes me realise I should update the lighting

Edited By AStroud on 19/12/2020 10:47:40

Here's what I did to remove a stubborn filter.

Put 2 jubilee clips over the filter body with their worm drives aligned and tightened up.

Found a piece of pipe with id the same as the jubilee clip bands' od. In one end of the pipe cross drilled for a tommy bar. On the other end notched out a circular segment of length such that the clips' worm drives would fit into it. Put the pipe onto the filter with the notch around the worm drives and then used a tommy bar to unscrew the filter.

Hi Mark

It is a Mk 111 about 35 years old, serial number is xxxxxE so in imperial. I managed to get it in good condition, looks like it is on its original belt and most importantly with some accessories including collets. I love it, only wish it was a bit bigger as we do with most of our machine tools.

Andrew

Thanks for the comments.

yes, one of my cheats on the MRM drawings, the flywheel is from a billet. Stretched my S7 and BCA to accommodate it but I am happy how it has turned out. For the first time I finish bored for the crankshaft and have been rewarded for what looks like a wobble free flywheel.

Andrew

First set out of the main assemblies of my Corliss, based on the MEM drawings

according to my James Walker design notes for O rings

for 0.125" cross section dia o ring

groove width = 0.159" - 0.164"

max piston groove dia = min cylinder dia minus 2 x (0.110" - 0.114" )

min piston groove dia = max cylinder dia minus 2 x (0.110" - 0.114" )

The design notes are available on the net and are well worth hunting down.

Andrew

Edited By AStroud on 05/08/2019 17:38:05

A BCA Mk 3 if it qualifies as a mill. I have it because of space limitations and it is a joy to use. Downside it is limited to small work but it suits my projects.

Andrew

Yes I do, but it is a reprint purchased from the lathes.co.uk website, quite pricey and a bit light in information but if you are a BCA enthusiast a must have I think.

Andrew

The spring keeps the belt at the correct tension, there is a clear instruction in the instruction book about adjusting the tension arm to the correct fixed length so the spring is compressed to keep the belt at the correct tension.

Andrew