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Member postings for geoff walker 1

Here is a list of all the postings geoff walker 1 has made in our forums. Click on a thread name to jump to the thread.

Thread: problem with rotary table
08/10/2018 13:27:19

Hi Ian, Michael,

I do remain intrigued as to the original 'failure mode' though ...

It's not really a failure as such Michael. The unit is generally well designed the action is very smooth with very little backlash. The problem as I see it is the outer rim of the table has very thin section whereas the inner part of the table has a boss underneath which stiffens it up. If you look at the set up in the earlier photo you can see that the engine frame is bearing down hard on the outer rim. This combined with the upward thrust of the tee nut is causing the rim to flex, not much, but enough to create friction between the table and the base. It's a design fault, if the outer rim was a little thicker I don't think there would be problem.

Geoff

08/10/2018 09:22:07

Hi All,

I have to say I was really disappointed with this little table of mine.

I didn't expect to have the problem I had. Having said that it was "cheap as chips" so I suppose you get what you pay for!!

Anyway I took Ian T's advice and made a small sub table. This is secured firmly by 4 screws nearer to the centre of the table. The underside of the sub table is relieved 3/4" in from the perimeter so no pressure is applied to the outer rim of the table.

No binding or flexing problems now and it should be ok for the work I have planned.

Geoff

20181008_082155.jpg

Thread: Vertical Boiler Fittings
08/10/2018 09:11:58

Yes, nice work Gary, I've followed this thread from the beginning.

Well done but like others I would love to see an engine running.

I have everything I need to make a boiler except the inclination.

Having seen your success I really must get on with it!!!

Geoff

Thread: Chester Champion V 16 Z axis mod
05/10/2018 07:46:00

You should be writing that up David!

Neil

Sounds good to me I'll second that.

M.E. or M.E.W., I would imagine both editors would be very interested

Geoff

Thread: problem with rotary table
05/10/2018 07:35:20

Hi All

Big thank you for all your replies, all of which are really helpful.

A little experiment last night revealed that clamping pressure on the outside of the rim causes the table to lock, when it's nearer the centre there is no problem. I set up a dial gauge as John suggested and you see the finger move as the table flexes, not much but enough to tighten it up. It's very frustrating, I'll have a good look at it this weekend.

Really like the idea of a sub table, I have one for my lathe cross slide, they are a good idea. It might help to even the load across the table

I'll report back on this one. Thanks to all again

Geoff

04/10/2018 17:31:22

20181004_150906.jpgI recently bought a mini rotary table. see photos

Today I was milling a curve in the aperture of engine frame.

My problem is that with the set up I had when I tightened the nuts the table became very stiff and it was really difficult to turn the handle on the table.

As you can see i have brass tee nuts, 4mm thread, which accept 4mm studding. the bar which goes across the frame is 1/4" m.s.

The more I tightened the nuts the stiffer the table. It feels like the tightening is distorting the table and thus creating unwanted friction between the table and base. That to me is illogical but I'm stumped for any other answer.

Any thoughts Guys20181004_143935.jpg

Thread: Milling/drilling spindle
02/10/2018 08:44:18

Steve,

I have a potts milling spindle which I use a lot.

I had problems with spindle end play and solved it by removing one of the adjustment collars and replacing it with a slim thrust ball bearing (from simply bearings). The remaining collar is squeezed lightly on to the bearing ring and the end float is gone, completely. I locked the collar in place with small grub screws to retain the setting.

My potts has plain parallel bronze bearings.

Geoff

Thread: Benchtop mill motor and head / spindle getting very warm
28/09/2018 12:42:37

Hi Ross,

There is a forum on the chester machine tool site.

There is a post describing how a cooling fan is fitted to keep the motor cool.

Not your mill but might be worth a look

Geoff

Thread: The Workshop Progress thread 2018
28/09/2018 12:38:35

Hi George,

I notice the pistons are bevelled. Never seen that before.

Presumably so that the piston will travel further and not cover the port hole.

....and you have that vee cut to aid compression.

Nice work Geoff

Thread: small cast iron flywheel
18/09/2018 18:00:56

I need a 100mm dia flywheel for my next engine.

The one supplied by ATELIER looks more or less just what I need.

Could I ask does anyone have experience of Atelier flywheels, usual disclaimer of course.

It's not a cheap flywheel but I don't mind the cost as long as the product is good.

Any comments appreciated

Geoff

Thread: Chester Champion V 16 Z axis mod
18/09/2018 17:31:52

Nice work David, is it your own design?

Looking forward to seeing it completed.

A you tube video of it in use would be a good idea.

Geoff

Thread: The Workshop Progress thread 2018
18/09/2018 17:27:30

Yes, very nice, as someone once said it's amazing what you find inside a big chunk of cast iron.

Hope you had a good clean up Brian!!!!

Geoff

Thread: Cleaning castings by hand
18/09/2018 15:31:03

Looks good to me Gary.

I like your approach, nothing wrong with adapting current equipment to meet an immediate need.

The problem is that it is very time consuming.

Sooner or later you may feel the need "to get on with things" and will need then need to expand your workshop equipment.

Geoff

Thread: The Workshop Progress thread 2018
12/09/2018 15:06:37

Nice work Jim, looking good.

Are those just very short studs in the cylinder end or are they extended into the cylinder wall thickness?

Keep the pics coming and can you put 6" rule in the pics so I get an idea of the scale.

ATB Geoff

Thread: WT2527 15cc Glow Engine
10/09/2018 09:15:46

Agree with everyone, great craftsmanship. You appear to have a very wide range of skills, the spitfire looks superb. Keep posting Craig, really interesting topic.

If I was betting man I'd say you probably laid that patio as well......?

Geoff

Thread: What did you do Today 2018
06/09/2018 13:25:38

20180905_143510.jpgCurrently making another Muncaster engine so I thought I would also make the simple reversing valve detailed in the 1912 book. Works well and will be incorporated into the new engine. Also gave me a chance to try out my "new toy".

Many of you will recognise the small circular table, sold by RDG which was great for the semi circular curves in the valve head.

Some feedback on the table. It's very small, 2 1/2" table diameter so only good for small scale modelling but is well made and I think good value.

Geoff20180905_143457 (2).jpg20180906_123533.jpg

Thread: double acting oscillating cylinder engine
23/08/2018 18:21:23

Hi Thor,

Thank you for the reply, some good advice.

I find the issue of which materials to use confusing and would expect people to have different viewpoints largely based on their own experience.

My experience is limited to two engines both of which had a cast iron cylinder and a gun metal piston. they have both worked well and my thoughts were that you could pair them the other way round, gun metal cylinder and cast iron piston, but I don't really know whether that is practical.

I feel I should point out that the well made parts in the photo are not mine, they are Jason's work from his new year oscillator

thanks again Geoff

23/08/2018 15:10:51

Hi All

My next steam engine will be a simple double acting oscillator, 5/8" bore 1" stroke.

I want to fabricate the cylinder in much the same way as Jason did in his new year oscillator by silver soldering the parts together. see photo below.

M Machine metals have LG2 gun metal in hollow and solid round, a material which I would favour for most of the fabrication. no particular reason I just like the material and as it is used a extensively for cylinders thought I would give it a try.

I assume gun metal ok for silver soldering, if so what grade of solder?

The piston material, cast iron? phosphor bronze? aluminium alloy? gun metal?

Any thoughts/comments as ever would be welcome.

thanks Geoff

jason cylinder.jpg

Thread: Murray's Hypocycloidal Engine - Antony Mount
05/08/2018 13:21:24

Nice work Mick, been a good thread this some interesting input

Geoff

Thread: The Workshop Progress thread 2018
30/07/2018 13:11:12

Another sumptuous example of craftsmanship Jason, well done

Like many others I envy not just your talent but the efficiency with which you turn out these lovely models.

Geoff

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