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Post by flyingfox on Jun 21, 2021 6:27:50 GMT
Phil, one option, if you have not progressed too far, is to tap the crosshead, and thread the piston rod end. This method give a strong connection, is removable easily, I have had very little joy with roll pins coming out easily, and there is a measure of adjustment available to get the piston in the middle of the cylinder, with equal dead space at each end. Regards Brian B
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Post by philh1aa on Jun 21, 2021 11:34:01 GMT
Thanks Brian but it is too late for that option. I am either going to go for a high tensile (silver steel) plain shank bolt or will use the same material and make a tapered reamer.
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Post by ettingtonliam on Jun 21, 2021 14:30:55 GMT
What size taper pin do you intend to use? If I've got the right size taper reamer, you are welcome to borrow it.
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Post by philh1aa on Jun 21, 2021 17:08:26 GMT
Thanks very much for the kind offer but I have noticed that the weighshaft parts are held with probably the same sized taper pins.
The script just says to drill through at 1/16" diameter and open up in stages with a No.52, followed by a No. 50 and a No.48 drill at different depths finishing with a reamer.
So I probably need to swallow hard, give myself a good talking to and get the silver steel out and make a reamer (D bit type thing) and get on with it.
I sometimes have these moments when I get unexpected work to do on this engine. I try to avoid it by thinking of alternatives then end up sticking to the script anyway.
Oh, unless you literally live round the corner. I am between Chester and Ellesmere Port.
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Post by ejparrott on Jun 21, 2021 21:24:59 GMT
£10 for a 1/16" taper pin reamer
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Post by philh1aa on Jun 22, 2021 9:47:02 GMT
Oh, prices I saw were in excess of £17. So for a one off connection - ok a few including the weighshaft - just seemed a bit ridiculous.
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weary
Part of the e-furniture
Posts: 290
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Post by weary on Jun 22, 2021 9:58:16 GMT
Less than £9 (inc. carriage etc.) for 1/16 taper reamer from ebay & RDG.
Phil
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Post by John Baguley on Jun 22, 2021 10:47:30 GMT
I keep my eye on Ebay and have bought several 'job lots' of reamers over the years very cheaply and now have dozens of various size reamers including taper ones. Ok, they are secondhand but many of them have had little or any use and still perfectly ok. As has been mentioned, you can get them for a tenner or less new. They may not be top quality but will be fine for occasional use. Zoro Tools have got 3/32" on Ebay for £10.38 and free postage.
John
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Post by philh1aa on Jun 22, 2021 11:34:49 GMT
Thanks everyone. I had obviously spotted an expensive version somewhere which prompted my initial post. I have just seen some on Tracy tools. £30 for a whole set or £10 each.
Also, I have two Rob Roy books. One of them has the William build attached and I notice that the it has a threaded piston rod and threaded crosshead - interesting!
I should have a careful look at the William section because I suppose it will have incorporated all sorts of lessons with about 20 years between their designs.
I am also getting closer to being able to post pictures - got a new phone at least. Next is a new laptop that will work - hopefully.
Phil H
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Post by philh1aa on Jul 6, 2021 17:19:06 GMT
Right chaps, the next question please;
I have threaded glands on by rear cylinder covers in accordance with the original design that calls for graphited yarn. How does everybody else pack their glands? I am probably too late to use O rings?
By the way, I am still unable to post pictures of my build to this site but I do have a build thread on the ME website under PhilH1.
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uuu
Elder Statesman
your message here...
Posts: 2,808
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Post by uuu on Jul 6, 2021 17:56:31 GMT
Graphited yarn works really well, so if it's "too late" to use an alternative, why not just go with the original design?
Wilf
PS - this site won't host pictures directly - you're best to use Flickr or some other hosting site and then generate the BBcode and paste it in here.
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stevep
Elder Statesman
Posts: 1,070
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Post by stevep on Jul 6, 2021 18:35:12 GMT
I second what Wilf has said. Posting pictures here (via a picture hosting site) is easy. Once you have done it, you'll wonder why you had problems.
There is a 'sticky' thread that gives all the details.
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Post by philh1aa on Jul 6, 2021 18:49:40 GMT
Yep, for whatever reason, this laptop which is 7 years old will not play ball. It simply won't allow me to upload flickr or imgur or whatever. I really do need a new machine.
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stevep
Elder Statesman
Posts: 1,070
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Post by stevep on Jul 7, 2021 8:02:18 GMT
I don't understand. Loading pictures to Flickr, and posting them on this board, is all done using the web browser. There is virtually no processing done on the laptop - so it should work with the oldest of machines.
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uuu
Elder Statesman
your message here...
Posts: 2,808
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Post by uuu on Jul 7, 2021 8:38:24 GMT
Ah - but Flickr says "Flickr on the web is browser-based.... Features may not work properly if you're using an older operating system (which can't be updated) or an outdated or unsupported browser."
Wilf
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Post by gwr14xx on Jul 7, 2021 8:46:29 GMT
I was also thinking it may be your browser that is causing the problems. For years, I have used Firefox, then a few months ago, my computer got very slow and eventually wouldn't let me access any WORD or EXCELL documents. After a while, I remembered that there had recently been an upgrade to Firefox - so restored my computer to an earlier date - Hey presto, my documents returned! I have now changed from Firefox to Brave for my browser, and my computer is now running as fast as it ever did!
Regards, Eddie.
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Post by doubletop on Jul 17, 2021 1:24:56 GMT
Thanks Nobby. By the way, I looked up Loctite 567 and noticed that it was a thread sealant for low pressure. Does the same gunge work on boiler fittings (for when I get there)? Can I suggest that Loctite 567 be replaced by Loctite 5770. I used 567 before I discovered 5770. It is medium strength so locks the joints better than 567 and it does come apart easily. Perfect for the boiler fittings www.henkel-adhesives.com/us/en/product/thread-sealants/loctite_5770.htmlI do like the fact that you've secured the drain cocks, having them loose would mean that the will leak and the last thing you want with a Rob Roy is any loss of power. On the use of O rings in the glands I've done that without any modifications. They work well. Something that you will need to be aware of is that you will be stripping it down a number of times before you are happy with the performance. As you add more and more parts something that seemed accessible is now buried deep. A bit of forethought will pay dividends later. This may be of use to you. www.homemodelenginemachinist.com/threads/rob-roy.8800/Pete
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Post by philh1aa on Jul 17, 2021 12:04:15 GMT
Thanks Pete.
I haven't bought any sealant yet, so moving to 5770 is still possible.
Can you remember what diameter of O ring that you might have used. Clearly, 3/16" and 5/32" bore for the main rods and valve rods but were they quite chunky to fill the void?
Yes, I suspect you are right regarding the strip downs. As an example, my cylinders have been on and off the frames about 4 times already and I haven't even finished making all the parts yet.
A superb thread showing the strip and painting etc. Thankfully, mine is starting to look quite similar as more and more parts are going on.
I also notice that your tanks have bottoms. Something I am considering too. I bought the cab and tanks from an ME exhibition, laser cut because they were on offer and seemed cheap when compared to buying sheet brass etc. However, they still look a bit flimsy in their flat state - so I suspect Ill be adding plenty of angle etc.
Despite encouragement and a bit of help etc, There doesn't appear to be any way that photos are going to appear on here using this laptop. I've got my build on the Model Engineering magazine website.
Thanks again,
Phil H
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Post by doubletop on Jul 19, 2021 5:05:58 GMT
Thanks Pete. Can you remember what diameter of O ring that you might have used. Clearly, 3/16" and 5/32" bore for the main rods and valve rods but were they quite chunky to fill the void? I also notice that your tanks have bottoms. Something I am considering too. I bought the cab and tanks from an ME exhibition, laser cut because they were on offer and seemed cheap when compared to buying sheet brass etc. However, they still look a bit flimsy in their flat state - so I suspect Ill be adding plenty of angle etc. Thanks again, Phil H Phil I'm afraid I can't remember what O rings I fitted, it was a while ago. Yes the tanks have bottoms. They do tend to be more useful as tanks when they have bottoms . Seriously you will need them to hold water and makes the loco more self sufficent rather than relying on a tanks on the riding trolley. I did put a small tank and pump on my riding trolley. It is low pressure model boat bilge pump that fills the tanks rather than high pressure to fill the boiler. Had my tanks not been useable I wouldn't have been able to bring the loco to the UK for the Rob Roy Rally as I wouldn't have been able to bring the riding trolley as well. Pete
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Post by philh1aa on Jul 19, 2021 15:35:28 GMT
OK, its just that the tanks on the drawings do not appear to have bottoms? I'll take another look but they appear to rely on the running boards to stop the water from falling out.
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