Member postings for Martin Shaw 1

I have a piece of BMS 6 by 30 by 100 long. I needed to reduce the width to 18mm. I wonder how others might approach this bearing in mind it's done on an SX2P, so not a big rigid mill. I've actually done the job to I think a reasonable accurate quality, but I wonder whether my approach was any where near right. I'll let you all know in due course how I did it, if I'm not going to embarass myself too greatly.

Regards

Martin

Hi Fowler's Fury

The two 2-8-0s that returned from Turkey came from Silvas shed in the eastern part of the country, and as far as I am aware have never been at the Camlik museum.

Regards

Martin

Peter

You are wholly correct, this is one of the pair returned from Turkey. One has been sold on as a static exhibit in Israel. The other one has been bought by the Scottish Railway Preservation Society for restoration to running condition. Our one, despite it's outward condition, is actually in an amazingly good condition. The boiler which is inevitably the most expensive bit to restore is in a good condition with very little sign of wear. Tubes and superheaters will need replacing of course, but the firebox sides show little signs of grooving and the stays are apparently mostly intact. Most of the non ferrous fittings are there, the injectors which were missing have had replacements purchased, as have the motion brackets which are currently somewhat bent. Nobody would pretend that it is inexpensive to restore, but it will certainly be a lot less than ex Barry loco. Donations to assist would be gratefully received at SRPS Steam.

Regards

Martin

You will rarely find a snifting valve on a saturated engine because they are usually fitted with slide valves that fall off the valve faces so the pumping action of the pistons is completely negated. A superheated engine will have one on the smokebox behind the chimney (a la Mr Gresley), or on the main steam pipes (a la Mr Riddles) and as Baz points out it is to relieve the vacuum so that char isn't drawn from the smokebox into the valve chest and cylinders. On a cold engine it's academic since you need steam pressure to close the snifting valve(s). When coasting on a piston valve engine the practice is to set the cut off about 45% and about 10-20 psi on the steam chest to buffer the piston stroke end, keep the lubrication flowing and prevent the superheating elements from overheating.

When towing an engine any distance the practice was to disconnect the wheels from the motion, where depended on the particular motion fitted. Certainly many older engines had a displacement lubricator and obviously without steam no lubrication would reach the valve chests or cylinders. If your going to move an engine that has been static for some while 1/2 gallon of lub oil down the blastpipe is worthwhile and stops the worst of the groans.

When a full size boiler cools the water level drops and at the point where there is no pressure left the regulator valve is no longer tight on it's face which is enough to prevent a vacuum forming.

Hope this helps

Regards

Martin

I can only second the sentiments expressed, Arc have had quite a bit of my money this year which I certainly don't begrudge them. The service and support have been excellent, and coupled with a desire to ensure I was completely satisfied to the extent of pointing me at another supplier for a particular item, makes dealing with them a pleasure. Well done all at Arc and a Happy Christmas from me.

Regqards

Martin

An update

I followed Russell's advice and drilled two holes. Because the existing holes are counterbored I calculated the volume which then gave me the size for drilling, following the advice of 0.7 resulted in an 8MM hole. This was easily enough done on the mill and I just spaced then equidistant by 18.5mm from the common hole. Back on the lathe there is a significant improvement, still a slight wobble at 1300-1400rpm but less than before and at the 900-1000rpm nice and steady. Without being able to dynamically balance or start from scratch I have a compromise that will at least allow use of the machine.

Regards

Martin

Alan

Yes quite probably, but the holes in the backplate are counterbored as well so whilst I could make three plugs, drilling two holes is obviously easier, and having got the backplate balanced it will remain with it's respective chuck for ever more. It's currently not very usable so worth having a go, and not too horrendously expensive if I make an a*** of it.

Martin

Russell

No doubt drilling extra holes is easier than plugging unused ones but may I ask whether the spacing from the common hole is critical or not and presumably they should be on the same PCD?

Regards

Martin

I have an SC3 and decided I wanted 4" chucks for all the reasons outlined above however whilst the 3" chuck is fine when I put the 4" backplate on there is a distinctly unpleasant vibration around 1000rpm, and thats before the chuck is fitted. There is a slight but noticeable movement between the spindle register and the backplate recess which is undoubtedly a major contributory factor as well as the unbalanced drilling in the universal backplate. I am discussing this with Arc and we will get to a satisfactory state in due course, but worth being aware of.

Regards

Martin

Hi Nige

I bought an SX2P from Arc earlier this year. I can only speak most highly of the service from Arc, the machine was delivered when promised, in proper condition, and when I had issues a phone call resolved everything without trauma. I was sufficiently impressed to subsequently purchase my lathe from them.

The choice of the SX2P was firstly weight, my workshop is in the attic so getting it up there was a large consideration and even with two of us a bit of a struggle.. Secondly cost, I spent £780 delivered which is a substantial enough sum, but I have since spent in excess of that in tooling, some of which might be considered luxury if your on a tight budget but I justified it to myself nonetheless. Thirdly but importantly ongoing support from the supplier, I don't think Arc are going to disappear. I've no doubt other suppliers can do as well.

In essence I think the SX2P could do most of what you wish however in hindsight I wouldn't recommend this particular machine for these reasons. The arrangement of the head movement via a rack on the column, both for coarse and fine movements, is sub optimal, especially with the counter torsion spring. A machine with a quill is IMHO necessary. It does work but not as well as it might. The lack of X travel stops on the table is undoubtedly a cost saving but could be an issue. The X and Y locking screws are a joke, I'm making something better.

Further thoughts, if you don't have any existing tooling to match in then get the R8 spindle taper, getting stuff out the spindle is much gentler, Don't bother with a tilting column, tilt the workpiece, it's much simpler. The brushless DC motor with a belt drive is very quiet.

This might sound as though I have aeons of experience, but really I'm just a beginner. I found Harold Hall's book most helpful and yes I did read it before I bought the machine.

Finally I think the hi torque version of the SX2.7 is where I would go if I were doing it again, it's not much smaller than the SX3 but is £460 cheaper.

Regards

Martin

Just remembered, be prepared to do a little lapping in on the dovetails and gib strips, they're a bit unfinished as supplied which seems to be a Sieg issue rather than anything to do with Arc. The quality and application of the paint is dire.

Edited By Martin Shaw 1 on 18/10/2017 14:34:04

Edited By Martin Shaw 1 on 18/10/2017 14:40:19

I though you might appreciate an update. Having stripped the complete saddle assembly it was obvious that both the dovetail of the cross slide and the surface of the gib strip were somewhat rough so the brasso came out and much rather mundane to and fro has polished up the rubbing surfaces nicely. They felt quite sweet when dry so with lubrication they are much improved. This was all done by hand without the leadscrew in place, and what remains is a slight tight spot which suggest a machining problem that I haven't quite polished out.

Having put the leadscrew back in and adjuted the nut properly it is much improved with almost complete lack of movement of the crosslide, except of course where it's meant to. I am much heartened by this, and if I can get the top slide as good it will at least make the lathe reasonably usable. At some point I am going to make a new gib strip that fits accurately into the space, whereby the adjustment screws will just be to snug it up and the strip won't then be able to rotate at all..

Regards

Martin

After all the useful posts I have been playing around. I managed to mill a fraction off the tip of the gib which made it fit snugly into the dovetail, but somewhat surprisingly if I reversed the gib it fitted perfectly which suggest it isn't a parallelogram in section. Either way nipping up the cone point screws did what was needed, the gib sat exactly where you would expect it to.

However I still couldn't get a satisfactory compromise where rigidity was maintained but ease of operation enabled, so I tried deepening the points in the gib, bad mistake, now the adjustment tipped the gib out of alignment. I think that this a partly due to drilling into a surface at an angle and on reflection it is the pointed dimple surrounding the cone point that maintains the correct angle to the dovetail. The brass gib now had so many wrong holes in it that the scrap bin beckoned. I reverted to the original steel gib but the other way around. This worked as described above so I thought maybe a centre punch would be adequate to maintain alignment of the gib, it does but by no means ideally and I have come to the conclusion that you should do no more than screw the adjusters tight to form a dimple and then adjust for operation.

The net outcome of this is that I will obtain a replacement brass gib from Arc, BTW you do have to polish out the machining marks to have a chance, mean while the steel one will do, but the optimum is not really satisfactory, rigidity is compromised by operability. I think the truth of the matter is that the manufacturing tolerances are sufficiently lax for the odd rogue to slip through, maybe I really am expecting too much. Thanks though for all the help.

Regards

Martin

Neil

I think we might be slightly at cross purposes. Looking from the front the two adjacent surfaces of the gib strip, left and bottom, should be in close contact with the inside of the dovetail and the top surface of the saddle. The right hand side obviously will be at a distance form the cross slide by virtue of the adjustment screws and the top doesn't want to contact the underside of the slide so it doesn't try to lift it. It is therefore I feel axiomatic that the fit of the gib strip into the dovetail is as close as needed without binding and cannot possibly be achieved if the corner of the strip bottoms out. This does assume that the angle of both the gib strip and dovetail are the same, are they?

You have pointed out other things I can look at as well so thank you for that.

Regards

Martin

Neil

Since my last post I have taken the top slide off, and holding the gib into the dovetail I can rotate it on its corner in the root of the dovetail, and not just a bawhair either. Unless I totally misunderstand the relationship between the gib and the dovetail it should be nearly a close fit on both sides, should it not? The gib screws have been changed to cone point and into brass form a pocket, whether this is deep enough I don't know. Tomorrow I'll strip the cross slide and see if that's the same.

Regards

Martin

Gents

Thanks for all the thoughts, it seems I'm not the only one who has this problem. Interestingly the 35 year old Cowells ME90 I also have works as sweetly and as solidly as you might wish. I appreciate it's unfair to draw the comparison, but never the less I have.

Lathejack's suggestion about the lack of clearance in the root of the dovetail is an interesting one and fairly easily checked and altered.

I found that I was also having a problem with the gib rotating and at Arc's suggestion repositioned the holes for the adjustment screws closer to the edge. Apparently they did this in the days when they prepared machines, and despite entreaties to Sieg, the Chinese didn't want to change their manufacturing process. It certainly improved things, but obviously not enough.

Neil

I can probably take the saddle assembly and compound slide apart with my eyes shut, it's been on and off that often, and I have your book on the subject, which by the way I found invaluable before committing serious money, but this is I think more than just a 'feel', or lubrication, there is something not right, or am I expecting too much for the cost of the machine.

Regards

Martin

Here we go

Nick

When I can work out how to do that I will.

Martin

I recently purchased an SC3 from Arc which I've had a few problems with. To be wholly fair to Arc they have been most helpful and accommodating in overcoming the issues and I have absolutely no complaint about them. Despite following their recent advice I'm still having difficulty with the cross slide gib strip, and I'm lost as to where I go now.

If the cross slide is sitting with it's left hand dovetail hard against the saddle dovetail, and the brass gib strip is also hard against the saddle gib strip, how much clearance would you expect between the gib strip and the cross slide dovetail? On mine it's about 1.0mm, maybe a tad more, this maybe right but I'm struggling to get the whole assembly tight enough to make the tool rigid whilst retaining sensible movement of the cross slide fed screw. Any thoughts?

Regards

martin

Jimmie

It's still fairly unusual to find individual stopcocks for tenement flats. When they were built the cold supply from the street runs under the close floor, branches into two and then runs up the kitchen wall to the attic. Each kitchen had a cold tap fed fron this, the attic cistern was typically built from 6" by 3" timber half lapped at the joints and then lead lined, about a 1000 gallons. A supply from this went down the building, each flat tapping off for bathroom cold and hot water cold feed, which is part of the reason why bathrooms were often at the front of buildings. What's the betting that your daughters bathroom is long and thin, and not really big enough for a bath.

I have been to one or two tenements where this cistern arrangement was still in use, but I wouldn't want to live under a 1000 gallons of water contained in a 130 or so year old tank. Didn't really want to go in the attic either, feet deep in pigeon guano at best. More recently when lead pipe removal attracted grants, flats were often repiped and everything connected to mains water, but a lot depended on the factors inclination. Your picture is most definitely not the stopcock but is the remains of a mechanical door bell.

Regards

Martin (in Glasgow)

I had some Castrol LM grease left over from the days when I had to fix my Land Rover frequently, so I used that. The chuck is a lot smoother, and since it's gone on the rotary table, stuff flying out isn't really a problem. I've no doubt that oil would work equally well, but the line of spatter up the face is too be avoided I feel. Thanks chaps.

Martin