Author Topic: Murdoch-Aitken "Steeple" engine  (Read 8011 times)

Offline scc

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Re: Murdoch-Aitken "Steeple" engine
« Reply #90 on: May 23, 2022, 08:07:30 PM »
Moving swiftly on......I set up the guide in my jig, marked out and drilled two holes for the slot ends then set to with a 5mm endmill. Opened out the slot to dimension  and all worked well.
Next I needed to drill the base.  I clamped my pre-drilled hole guide to the crosshead guide and then had to improvise :headscratch: Lacking anything better, I came up with the set-up in the photos! The process was to position as close as possible and clamp tight. Gentle taps with a hide hammer knocked things to where the drill bit would just slip into the hole without any deflection ;) Repeat for the 15 other holes.
Next up was to tap the 16 holes in the "table"  10ba.   Busy with other stuff for the rest of the week , then camping at the weekend :whoohoo: :whoohoo: :whoohoo:     Hopefully more progress next week.            Terry

Offline Admiral_dk

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Re: Murdoch-Aitken "Steeple" engine
« Reply #91 on: May 23, 2022, 09:13:24 PM »
Great to see you back on this build + that you found a renewed interest in it  :cheers:

Per

Offline scc

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Re: Murdoch-Aitken "Steeple" engine
« Reply #92 on: May 23, 2022, 09:31:41 PM »
Cheers Per :cheers:

Online Kim

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Re: Murdoch-Aitken "Steeple" engine
« Reply #93 on: May 23, 2022, 10:00:52 PM »
Wow, quite a setup you used there in pics 5 & 6 to get at the ends of those castings!  Looks like it would be a challenge to line up the spot for the hole!

Kim

Offline scc

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Re: Murdoch-Aitken "Steeple" engine
« Reply #94 on: May 24, 2022, 09:42:55 PM »
Yes it was a bit Kim!   but gentle taps with the hide hammer brought the non-running drillbit so that it could be lowered into the jig hole concentrically. at that point start the machine and drill the hole....   with a 1.4mm drill you can see and feel it when it is not lined up.
I am sure that when Jo does her's she will have proper  tooling for the job and we will see how it should be done.        Terry

Offline Jo

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Re: Murdoch-Aitken "Steeple" engine
« Reply #95 on: May 24, 2022, 09:53:16 PM »

I am sure that when Jo does her's she will have proper  tooling for the job and we will see how it should be done.        Terry

I will be digging out my old shaper box table  ;)

Jo
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Offline scc

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Re: Murdoch-Aitken "Steeple" engine
« Reply #96 on: May 31, 2022, 07:59:14 PM »
I decided to machine the big end rod next. Having been warned about it's crosshead hitting the table I thought it best to check. I don't "do" CAD so just used a pair of calipers. On my castings there would be interference if made to drawing.  The solution would seem to be to mill a tad off the inside of the webs that form the underside of the table to enable the crosshead from the bigend rod to fit inside them. I will measure properly in case the rod needs to be shorter.  Progress will be even slower soon as I have aquired two motorbikes to restore.       Terry

Offline scc

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Re: Murdoch-Aitken "Steeple" engine
« Reply #97 on: June 03, 2022, 09:02:44 PM »
Today I made a start on the big end crosshead.  Several methods, I settled for cutting from solid bar rather than fabrication.  A bit of milling
and some filing.....mostly by eye as I do not like filing buttons.  The two webs on the table were relieved and leaves enough clearance.  Another measure tells me that bigend con rod is too long as drawn so will be made to suit.   Terry

Online Kim

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Re: Murdoch-Aitken "Steeple" engine
« Reply #98 on: June 03, 2022, 10:41:43 PM »
The part looks fantastic, Terry!   :popcorn:

But what causes your dislike of filing buttons?  Just curious.  I find that my eye isn't very round.  I have much better luck using filing buttons myself. Must be my astigmatism!  :Lol:

Kim

Offline scc

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Re: Murdoch-Aitken "Steeple" engine
« Reply #99 on: June 04, 2022, 09:52:13 AM »
Hi Kim,     Thanks for your interest.    Soft buttons are not a lot of use and hardened ones ruin files which are costly to replace.  I take the easy way out and do it by eye ::).  Parts end up adequate for my use as they not intended to appear at shows, etc.       Regards    Terry

Online Kim

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Re: Murdoch-Aitken "Steeple" engine
« Reply #100 on: June 04, 2022, 03:10:01 PM »
Soft buttons are not a lot of use and hardened ones ruin files which are costly to replace.

Interesting... I never thought about that before!
Thanks for taking the time to explain it to me :)

Kim

Offline Jo

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Re: Murdoch-Aitken "Steeple" engine
« Reply #101 on: June 04, 2022, 03:48:09 PM »
It takes a good eye to hand file curves. Well done Terry  :wine1:

For those who can't  Soft and hard buttons....

I use soft buttons and I screw them tight against the item. Often I will use marker pen on the buttons and when filing try not to catch the buttons but use them as an indication that that bit doesn't need any more filing. Also as the additional width of the buttons means it supports the file and keeps the edge of the item square. Soft buttons can be used when you draw file across the item as well as following the curve  :)

Hard buttons are used loose  on an arbour: Because they are hard they must rotate away from the file when it tries to rub against it. What Ray has said about hard buttons wearing the files occurs if the buttons do not freely rotate and you cannot draw file the other way without risking damage  :hellno:.

You an also use freely rotating soft buttons  :)

I am sure Jason will be along in a mo to tell us all about using rotary tables  ::)

Jo
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Offline Jasonb

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Re: Murdoch-Aitken "Steeple" engine
« Reply #102 on: June 04, 2022, 03:56:43 PM »
Rotary tables are so last century have you not heard of the new fangled CNC :Jester:

Must admit now that I also have the SX2.7 sitting in the workshop one of the rotary tables seems to live on that so it is quick and easy to use that for rounding over. And a carbide milling cutter will round off hard iron which would otherwise round over your file's teeth. The mechanical methods do also have the advantage of being able to round over solid items so you don't need a hole for a pin like you do with buttons

The one problem with buttons is that you can only roll the file on them for 180deg, a part like Terry shows has a longer arc which is not an issue when milling but means you start having to file across the buttons which will either wear if soft or muck up your files as he says.

I do still make use of buttons, I've never hardened them (also use loose)and they generally last for more than the job they were made for so can be kept in a box for future use and easy enough to knock up a pair of new ones from mild steel. Buttons also work well with a linisher but make sure you have them secure as they do spin up to quite a speed.
« Last Edit: June 04, 2022, 04:06:39 PM by Jasonb »

Offline crueby

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Re: Murdoch-Aitken "Steeple" engine
« Reply #103 on: June 04, 2022, 04:05:10 PM »
Rotary tables are so last century have you not heard of the new fangled CNC :Jester:

...
I use CNC on my rotary table...  Count Number Cranks, right?!   :Jester:




Offline scc

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Re: Murdoch-Aitken "Steeple" engine
« Reply #104 on: June 05, 2022, 12:52:52 PM »
Last century maybe but that's when I did my engine fitter appreticeship. :old:  Two years of filing / benchwork,etc.,  then shapers, vertical and horizontal boring machines and a huge variety of lathes.
There must have been milling machines but I don't recall seeing any and had no experience of them until aquiring my little Raglan.  Hence my reluctance to do this little parts on the mill and stick to filing.
Thanks for the compliment Jo,  but a hand finished part rarely compares well with a nicely machined one.  I continue to delight in the craftsmanship that you all display. :Love: :popcorn:         Terry