Author Topic: Len Mason's "Mastiff" - chewed from the solid  (Read 53776 times)

Offline b.lindsey

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Re: Len Mason's "Mastiff" - chewed from the solid
« Reply #45 on: November 01, 2016, 02:52:59 PM »
Looking great DT. Its nice to see the various pieces together in a family shot!

Bill

Online gbritnell

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Re: Len Mason's "Mastiff" - chewed from the solid
« Reply #46 on: November 01, 2016, 02:57:59 PM »
DT,
Chewing parts from solid becomes addictive when you see the finished results.
gbritnell
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Offline Dave Otto

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Re: Len Mason's "Mastiff" - chewed from the solid
« Reply #47 on: November 01, 2016, 03:56:42 PM »
Looks very nice DT

Dave

Offline deltatango

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Re: Len Mason's "Mastiff" - chewed from the solid
« Reply #48 on: November 15, 2016, 12:36:04 AM »
Many thanks for the encouragment everyone! The next bits are the timing case and its cover which are better made as a pair to get the outer shapes to match closely. The detailed shape isn't all that critical but any misalignment will stick out like the proverbials.

As usual the parts started as squared-up billets, marked out as carefully as I could using slip gauges on the surface plate. Then into the mill to bore the holes for the cam- and crankshafts:



Building a nest on the mill-drill table means you can bore the holes for the auxilliary drive shaft for the contact breaker and the oil pump from both ends and be sure of them lining up:



Then on to the faceplate to bore out the chambers for the timing gears:



setting the depth of the bores with slips from the saddle stop:



and digging out the chambers:



 When I tried the timing case on the crankcase the shaft centres didn't quite match the centres of the holes that have to clear the bearings (sorry, no picture, I was thinking "Oh bother", or words to that effect, at the time and worrying about how to correct things). Time for deep breaths and careful measurement:



It looks like the only thing I got spot-on on the crankcase was the shaft centre distance (phew!) the shafts were 10 to 20 thou off centre in the block, not a lot but then I'd goofed with setting up the timing case for the very first bores. May have messed up the arithmetic with the edge detector, don't really know. Anyway, there was just enough metal to re-bore, so back into the mill:



With that experience behind me I marked out and set up the blank for the cover plate very carefully and drilled and bored the main holes and fixing holes:



Most of the cover plate is only 1/8th" thick and I removed a lot of material in the mill:



before turning a steel mandrel to locate the plate from the distributor mounting hole and turn away the rest to thickness:



To get the outsides of the case and cover to match the final fixings were drilled and tapped:



and the fixing screws used to keep everything lined up while the outside was carved to shape:



The surface finish from the face mill isn't the best (probably needs flood coolant) but I'm less concerned with this now; my experience so far is that the surface gets damaged with further clamping etc and will need a final clean-up anyway.

The products look like:



The "family group" this time is slightly faked using Blu-Tack as I want to leave drilling the fixing holes into the crankcase until I can check the meshing of the auxilliary drive gears:



With this experience of setting up errors a DRO for the mill, plus an electronic edge finder, have gone on the Christmas list!
I think I need a rest from carving Al alloy for a while and the next bits will be the camshaft, tappets and timing gears.

DT
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Offline steamer

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Re: Len Mason's "Mastiff" - chewed from the solid
« Reply #49 on: November 15, 2016, 01:06:06 AM »
Consider the use of some "Toolmakers Buttons"  next time you're locating stuff like that....I think it's far easier, and more accurate.

Dave
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Offline deltatango

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Re: Len Mason's "Mastiff" - chewed from the solid
« Reply #50 on: November 15, 2016, 01:12:30 AM »
Thanks Dave, that is a very good idea (and a kick in the right direction towards doing things properly).

I've read several descriptions of using buttons but never yet tried the method. When you're self taught there's always a lot of things you miss out on.

DT
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Offline steamer

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Re: Len Mason's "Mastiff" - chewed from the solid
« Reply #51 on: November 15, 2016, 01:18:33 AM »
No problem DT..    Go to this post   Page 2

http://www.modelenginemaker.com/index.php?topic=237.10

I machined my oil pump using toolmakers buttons to locate the gears.   Once I had the mesh correct, and the buttons tightened down, you slide the gears off and set up on the lathe or the mill and locate on the button.    Then machine.

Dave
"Mister M'Andrew, don't you think steam spoils romance at sea?"
Damned ijjit!

Offline steamer

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Re: Len Mason's "Mastiff" - chewed from the solid
« Reply #52 on: November 15, 2016, 01:19:34 AM »
Buttons can be any convenient diameter, like the ID of a gear for instance.   They need to be round, and the ends square.

Dave
"Mister M'Andrew, don't you think steam spoils romance at sea?"
Damned ijjit!

Offline steamer

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Re: Len Mason's "Mastiff" - chewed from the solid
« Reply #53 on: November 15, 2016, 01:27:27 AM »
Take a look at reply #443 ....it shows the idler gear button being used to as a spindle to locate the idler gear mesh just so.

Dave
"Mister M'Andrew, don't you think steam spoils romance at sea?"
Damned ijjit!

Offline deltatango

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Re: Len Mason's "Mastiff" - chewed from the solid
« Reply #54 on: November 15, 2016, 10:41:23 AM »
Hm, I was wondering just how I'd line up the cylinder centre lines with the crankcase holes, maybe I now know how!
Thanks, Dave - DT
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Offline kevin beevers

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Re: Len Mason's "Mastiff" - chewed from the solid
« Reply #55 on: November 27, 2016, 06:39:13 PM »
hello,i am new here and just looking around and would like to say that is a great job
kevin

Offline deltatango

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Re: Len Mason's "Mastiff" - chewed from the solid
« Reply #56 on: November 28, 2016, 03:07:42 AM »
Hi Kevin
Welcome! I haven't been a member for very long myself.  Keep looking around, there is a lot of information and a lot of very knowledgeable and helpful people on the forum.
DT
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Offline Roger B

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Re: Len Mason's "Mastiff" - chewed from the solid
« Reply #57 on: December 09, 2016, 09:53:56 PM »
I'm still following along and enjoying  :ThumbsUp:  :ThumbsUp:  :wine1:
Best regards

Roger

Offline deltatango

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Re: Len Mason's "Mastiff" - chewed from the solid
« Reply #58 on: January 25, 2017, 12:12:20 AM »
After rather a long break its time to show some progress with Mastiff. Apart from all the other very welcome family activities we were away from home over Christmas. In mid-December we welcomed our younger son and his wife back to Australia after 10 years in the UK. They will stay with us until they find jobs etc etc… This very welcome disruption has lead to a clear-out of the house and somewhat of a loss of workshop time.

As a change from carving Al alloy I made a start on the cams, camshaft and camshaft drive. The tappets are straight-forward items needing only some hexagonal stock to be made for the locknuts and silver steel with two flats for the heads:



The bodies are from ¼” silver steel, hardened and polished. The family got together and bought me a macro lens for my birthday so there will probably be too many very close up shots in the log for a while. However, each finished tappet assembly looks like:



The two camshaft bushes in the block obviously need to line up but on checking before going any further, they didn’t. The timing end bush was spot on, the other end not so good, in fact a 3/8th shaft wouldn’t enter it. The cause of the mess up is lost in the mists of 2016 but it had to be fixed with an eccentric bush. The misalignment was estimated by using a sharply pointed rod to mark the correct centre on a dummy bush and then set this up in a four-jaw chuck to drill and ream:



The new bush was drilled at the same setting and silver soldered to a disc of gunmetal prepared in the soft jaws:





And trimmed square:



With a 3/8th rod for location the flange outline was scribed on and the fixing hole locations set:



OK, now it lines up, ready for the camshaft:



Now I just have to remember to drill the oilways!

DT
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Offline Art K

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Re: Len Mason's "Mastiff" - chewed from the solid
« Reply #59 on: January 25, 2017, 02:19:00 AM »
DT,
Glad to see that you are up and running again with good progress. I like your creative fix to an off center bushing boss. I probably would have set the block back up re-machined it and put in an oversized bushing since I wouldn't be comfortable that I had it centered right. Your solution gets the same result w/o the extra setup. Great job...
Art
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