Author Topic: Stuart Major Beam Engine  (Read 33842 times)

Offline Chipmaster

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Re: Stuart Major Beam Engine
« Reply #180 on: October 25, 2019, 10:26:45 PM »
Hi Willy, I'm glad the Stuart Major straps aren't as elaborate as the straps you're having to make for your Bressingham engine model. The Parallel Motion is a prominent part of the engine which needs to be well finished so I have a lot of polishing to do.
By the way how was the Forncett event this year, any pictures?

Andy


Offline scc

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Re: Stuart Major Beam Engine
« Reply #182 on: November 02, 2019, 09:45:17 PM »
Lovely work :popcorn:            Terry

Offline jeff l

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Re: Stuart Major Beam Engine
« Reply #183 on: November 03, 2019, 01:26:00 AM »
very nice work !

Offline Chipmaster

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Re: Stuart Major Beam Engine
« Reply #184 on: November 19, 2019, 06:57:35 PM »
Thanks Terry and Jeff,

I have made a little progress with the 'Lower Motion Link Bush' part No 68 which are split bearings, four required. I used bronze instead of brass, but encountered a milling machine malfunction along the way which has prevented any further work involving  milling, more about that in another post.

Here is an extract from the plan.
Lower Motion Link Bush by Andy, on Flickr

A straightforward approach for making split bearings, half of a 3/4" bar was milled away, half of the milled section sawn off then the soldered back on for machining. However, the outside of these bearings is rectangular with thin shoulders. I thought I should end up with four identical bushes if they were machined together from a bar.

Lower Motion Link Bush x 4 by Andy, on Flickr

Soldered

Lower Motion Link Bush x 4 by Andy, on Flickr

I went in with a parting off blade to form the shoulders of four embryonic bushes then put the bar in a square collet block taking care to ensure correct orientation of the soldered join. The plan being to mill the bar to the required rectangular profile then use a 3/16 end mill to form the 1/4" wide faces in between the shoulders.

Lower Motion Link Bush x 4 by Andy, on Flickr

Lower Motion Link Bush x 4 by Andy, on Flickr

Parted off and cleaned up

Lower Motion Link Bush x 4 by Andy, on Flickr

The better sides.

Lower Motion Link Bush x 4 by Andy, on Flickr

Irregular shoulder thickness.

Lower Motion Link Bush x 4 by Andy, on Flickr

Buffed up

Lower Motion Link Bush x 4 by Andy, on Flickr

Unsoldered

Lower Motion Link Bush by Andy, on Flickr

I'm not entirely happy with these bearings and may have to make them again, it will depend on how they fit in conjunction with the upper motion link bushes (parts 66 & 67) and even more important - whether I can hide the chewed up bits from view, I've managed to conceal them in my pictures!
Perhaps the method used wasn't appropriate, any suggestions for an improved approach would be most welcome.

Andy
 
« Last Edit: November 19, 2019, 07:26:13 PM by Chipmaster »

Online Jasonb

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Re: Stuart Major Beam Engine
« Reply #185 on: November 19, 2019, 07:41:27 PM »
I usually machine some bits of bronze block to half thickness in your case 1/4 and a bit over size in the other two dimnsions. Then tin and sweat together. I will then machine to overall size on the mill then if small drill and ream in the mill or bore in the lathe if larger. Finally hold in vice and mill the grooves.

Nice sharp milling cutter on the small ones and big for that matter especially if a soft GM bearing so you don't have much in the way of burrs to clean up..





If you want a turned lip then follow by holding on an arbor


Offline crueby

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Re: Stuart Major Beam Engine
« Reply #186 on: November 19, 2019, 07:46:54 PM »
Jason, on yours do you silver solder or soft solder?

Online Jasonb

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Re: Stuart Major Beam Engine
« Reply #187 on: November 19, 2019, 08:08:15 PM »
Soft, don't see the point of anything stronger as you will be taking it apart after machining and it is also easier to clean off the solder afterwards with a quick rub on wet and dry.

Offline Chipmaster

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Re: Stuart Major Beam Engine
« Reply #188 on: November 19, 2019, 08:25:47 PM »
Thanks Jason, I'll make them one at a time when I do that again.

Andy

Offline Chipmaster

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Re: Stuart Major Beam Engine
« Reply #189 on: December 02, 2019, 08:39:40 PM »
To make the 'Upper Motion Link Bushes' = radiused part 66 and square part 67 following the normal split bearing routine and followed Jason's advice making them one at a time, well almost..

Lower Motion Link Bush by Andy, on Flickr

Here I'm milling the rebate with confidence now that I have resolved my milling machine lead screw problem.

S Major 0702 by Andy, on Flickr

Unsoldering the halves

S Major 0705 by Andy, on Flickr

Machining the radiused parts

S Major 0706 by Andy, on Flickr

Then came the Motion Link Spacer Bushes

Motion link spacer bush by Andy, on Flickr

For these I was fortunate to acquire a form tool from another MEM member (thanks Jeff L). I started the job by roughing out then the form tool did the rest at a low speed and a copious amount of cutting oil.

S Major 0710 by Andy, on Flickr

S Major 0711 by Andy, on Flickr

S Major 0712 by Andy, on Flickr

With the bar held in a square collet block I marked out the rectangular ends and milled the 'bar end' to shape. i used a linisher to shape the other because I thought milling would rip it out of any of my workholding devices

S Major 0717 by Andy, on Flickr

Here is the first spacer and the set of Upper Motion Link Bushes,

S Major 0719 by Andy, on Flickr

I finished the third spacer this afternoon, it's a slow process with the roughing out followed by going in with the form tool using very gentle feeds at slow speeds. I have had one 'dig in' that destroyed a spacer when I tried too much force feeding in the tool.

Andy

Offline Johnmcc69

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Re: Stuart Major Beam Engine
« Reply #190 on: December 02, 2019, 11:49:37 PM »
Great looking parts Andy!  :ThumbsUp:
 :popcorn:
 John

Offline crueby

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Re: Stuart Major Beam Engine
« Reply #191 on: December 03, 2019, 12:45:14 AM »
So you put the halves that needed the radius together to turn the outsides, then put each half with a square half? Clever!

Offline jeff l

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Re: Stuart Major Beam Engine
« Reply #192 on: December 03, 2019, 12:56:15 AM »
Happy to see that the form tool worked well for you .

Offline Chipswitheverything

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Re: Stuart Major Beam Engine
« Reply #193 on: December 03, 2019, 12:35:29 PM »
Hi Andy, pleased to see your continuing progress with the interesting little bits of the parallel motion, all coming on very well.  When i got those four links all done, embarrassingly long ago!, I felt pretty chuffed because they do look interesting and very decorative and it seems like a good step forward on the Major build as a whole.   Dave

Offline Chipmaster

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Re: Stuart Major Beam Engine
« Reply #194 on: December 07, 2019, 05:28:21 PM »
Cheers Dave, progress is being when my workshop isn't too cold. I've really got in to making the Motion Link Spacer Bushes using the form tool from Jeff L, there are four plus two spares so far. At first I had my lathe turning at 35 rpm using an anonymous cutting oil. however, after a couple of failures I increased the speed to 350 rpm used CT-90 Cutting and Tapping Fluid and the form tool went in very easily.

Here are some of the 'interesting little bits of the parallel motion' in a tin awaiting assembly,



Now I have to make four more pairs of the rectangular Lower Motion Link Bushes to replace the rejects (taped together) in the tin which I made a mess of. The bearing halves are not even and the rebates are all over the place.

Andy