Stuart Twin Victoria (Princess Royal) Mill Engine

[Dr_GMJNParticipant @dr_gmjn]

OK I’ll try to flatten somehow later. If it works I’ll do the others un-treated.

Would you say soldering the boss will affect the straightness?

[JasonBModerator @jasonb]

Probably not but I would soft solder it on first. Or as you are going to milliput the internal fillets you could just stick them on with JBWeld or Loctite.

Lust be careful not to apply pressure to the middle when flatting as there will be some spring in them

[Dr_GMJNParticipant @dr_gmjn]

I made a jig to speed things up – worked OK but I’m now out of material.

I’ll do the profiling this week.

At present they are flat, so it’s definitely the machining that’s caused the distortion.

I think I’ll use JB Weld for the bosses.

[Dr_GMJNParticipant @dr_gmjn]

Got some more material and started on the remaining four bars. Got them all to the stage where the profiles are milled and the holes drilled.

I think tomorrow evening I’ll try to spring them flat(ter), then mill the central bit for the oiler bosses on the upper bars, then mill the slopes.

[Dr_GMJNParticipant @dr_gmjn]

Milled the angles. I had sprung them flat using a 3-point bend in the bench vice, but now the 0.003” bow is back. I’ll spring them again, then flat on the surface plate. Hopefully they’ll stay put eventually. Next job is to make the oiler bosses and JB Weld them in place.

 

 

[JasonBModerator @jasonb]

Out of interest is the spring the same on all of them or have the top one smoved more?

[JasonB]

On JasonB Said:

Out of interest is the spring the same on all of them or have the top one smoved more?

Surprisingly they’re all about 0.002″ – 0.003″

I was wondering whether to just mount them in the vice and skim them flat with the shell mill. Then again if I remove any stress from the bottom by skimming them, they might go the other way…

Perhaps re-bending and flatting them with abrasive paper on the surface plate is the best (but time consuming) idea?

[JasonBModerator @jasonb]

If it is an even arc then it won’t be that easy to bend it out, particularly the top ones which are likely to just bend where the oiler socket has been cut.

You could skim one of the the top ones and see how it goes, maybe mill off 2/3rds of the material and then just do the last but on the abrasive.

[JasonB]

On JasonB Said:

If it is an even arc then it won’t be that easy to bend it out, particularly the top ones which are likely to just bend where the oiler socket has been cut.

You could skim one of the the top ones and see how it goes, maybe mill off 2/3rds of the material and then just do the last but on the abrasive.

Yes. Problem will be making sure the sliding faces end up parallel to the square end-faces on the opposite sides. I machined the longitudinal edge depths to the DRO, but any side-to-side step there could throw things out.

I could support them on the end faces I guess, with some thin parallels.

[Dr_GMJNParticipant @dr_gmjn]

It was tricky to get them flat in the milling vice to machine them flat, so I sprung them as best I could in the bench vice. It didn’t take much to get them flat using abrasive paper. Some of the upper rails have some small flaws in the surface, but they won’t be visible, and the surrounding material should give more than enough bearing area I think.

[Dr_GMJNParticipant @dr_gmjn]

Started on the bosses. Turned some steel to 5mm diameter, centred, drilled, tapped and parted them off, then screwed them onto a 7BA stud held in the chuck for parting and chamfering. Had to do it in two stages due to the drill and tap not being long enough (this became irrelevant, but there we go):

Unfortunately, two of them are not drilled centrally. I guess the drill wandered a bit, so I will have to re-make those two.

 

Overall I think the proportions will look OK once complete.

 

[Dr_GMJNParticipant @dr_gmjn]

Just wondering – the oil holes are 1mm drillings. The oil will probably run straight out of the oilers.

Would it be acceptable to plug the bottom of the bosses with JB Weld when I attach them to the bars, then make a much smaller pinhole through it with some wire? That might make more of a restricted drip feed.

[JasonBModerator @jasonb]

The usual way to regulate the flow is to put natural wool into the hole, usually done on larger oilers where there is often an upstanding tube in the middle and the wool acts as a wick but can also be used to slow the flow.

I tend to use 1mm or 1.2mm for oil hole slike this and don’t restrict the hole. I drop of oil is good enough for an hours running, once it gets spread on the surfaces it will tend to stay there.

Good luck pushing a wire through JBWeld, you will need a small drill.

I probably would not have done a chamfer on the top of the bosses, as your intension it to make them look like cast bars then the boss would just have been machined flat. Could just turn the bosses upside down rather than remake as the Milliput will hide the chamfer

[Dr_GMJNParticipant @dr_gmjn]

Thanks.

I did wonder about the chamfers after I’d made them. They’ve also restricted the room for a Milliput fillet. I’ll turn the first two upside down – the chamfers are hidden in the counterbore I milled in the bars. I’ll still need to re-make two bosses though.

When I said use wire for the hole, I meant push it through while the JBWeld was wet, and leave it until it went off a bit – obviously with some grease on the wire to release.

[Dr_GMJNParticipant @dr_gmjn]

Finally got these finished today after a few weekends away. I think they look OK, and they seem to have stayed flat. There is no gap visible when placed face-to-face and held up to light, and they can be wrung together.

Next up are the pedestals and the spacers for them, so I can start assembling the whole cylinder ends of the beds and get things aligned.

 

[Dr_GMJNParticipant @dr_gmjn]

Second attempt at the valve rod ends. This time used a Stephenson block (as suggested) to hold in the milling vice for the flats and through-hole. For some reason, one of the holes seems very slightly offset. I used the centre finder on each side of the milled shaft, and halved the DRO value, and used the stiff centering drill to initially mark the hole, so they should have been spot-on. Still, I think they are OK for what they have to do – it’s a small error:

Made some filing buttons to get the radii consistent:

And finally chamfered, drilled and tapped the ends in the lathe:

So a bit more progress:

 

 

[Dr_GMJNParticipant @dr_gmjn]

I noticed that one of the oval packing glands on the valve blocks causes the shaft to bind when it’s fitted.

The other side is fine.

What’s the best way of addressing this?

Thanks.

[ZanParticipant @zan]

Reamer

[Dr_GMJNParticipant @dr_gmjn]

I think I did use a reamer on the individual parts, but how would I know which hole it’s aligned with on the assembly – the brass or the iron? The other end of the rod needs to fit in the guide hole in the opposite end of the valve block, so if the reamer follows the brass, chances are the rod won’t then fit the guide hole.

[JasonBModerator @jasonb]

Reamer has worked for me in the past. You can also ease the gland hole in the chest or the dia of the gland to allow it a bit of “float” so that it will find it’s own position and that is the way I tend to build them.

[Dr_GMJNParticipant @dr_gmjn]

Thanks, I’ll try easing the O/D of the gland spigot. I don’t think it will need much – maybe even wet & dry might do it.

[Dr_GMJNParticipant @dr_gmjn]

Continued with the crosshead by making the pillars and spacers

Always frustrates me that there’s no easy, accurate way of determining how far the tailstock is being extended. Resorted to a bit of tape to get consistent depths.

I made a fixture for the chuck by facing some steel, then drilling and tapping it and fitting a screw. I could then fit each stub in there and know it was against a hard datum. Didn’t ensure concentricity though.

Test fitted for separation, before all spacers were faced at the same setting (as above). By some miracle the first cut turned out to give what appears to be a perfect sliding fit for all four brass sliders. Which was nice.

Set the tool so it was perpendicular to the work, trying to ensure equal radii at each end of the necked part:

TBH I was initially turning to scribed marks at each end to establish the datums, and must have misjudged one. The lands were unequal, and required more work. They’re not exactly right now, but seeing as they’re decorative, and will be painted, I let it go.

Pillars (all OK):

Spacers (a few unequal lands):

Test assembled:

Couldn’t resist balancing the rest together to see how it was looking:

It looks nice so far, but it has to be said it doesn’t seem to reflect the amount of work that’s gone into it just yet.

[JasonBModerator @jasonb]

Looking good.

Does the Myford not have a graduated handwheel for the tailstock or at the very least graduations on the barrel? I make use of both on my warco depending on the accuracy needed.

[Dr_GMJNParticipant @dr_gmjn]

Graduated barrel, but so coarse that it’s not much use. I ought to figure something out, like a DRO, at the expense of making it look a bit odd. Also not sure how it would stand up to the shock of having Morse tapers knocked out.

[Harry WilkesParticipant @harrywilkes58467]

Like a lot of people I fitted a 6″ digital caliper on my tail stock others I’ve seen have used these digiral readout bars

H

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