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Member postings for Dusty

Here is a list of all the postings Dusty has made in our forums. Click on a thread name to jump to the thread.

Thread: darjeeling locomotive
13/01/2011 09:26:31
Peter
        As I see it, the tank mounting brackets are on the inside of the frames and the cylinder mounting plates on the outside. How do they foul? I have not started my build yet but have a full set of drawings plus the works drawings available.
Thread: My Best Christmas Present!
12/01/2011 09:53:56
Hi Nick
      No it is not a myth. I can remember visiting relatives in Ipswich in the 60's, travelling by train. Just outside Colchester was the Colchester lathe company. Between the railway and the factory were row upon row of lathe bed castings. They had been there for some time as they were all red rusty. I mentioned this to my boss at the time, an engineer of some repute, he told me that they left them like that for about 18months after they had had a light skim on a couple of faces.
Thread: Drilling Hardened Rivet
09/01/2011 20:50:26
James
        These are something called a drive pin. They are a blind rivet as you say but they have helical serations on them (rather like a very coarse thread). They could be described as metal nails as they are driven in with a hammer. They are almost impossible to remove. The only way that I know of to remove them is to try and remove the belt speed plate without damaging it too much. Then make up a tapered wedge to go under the head. Then gently tap the head of the drive pin while taping the wedge in. There is the danger of bursting the casting and you end up with a crater. For your information the hardness is like a masonry nail. I would have thought drilling was a non starter. I would be tempted to grind the head off, remove the plate and when replacing it move it up or down 5/6mm and re-drill.
Thread: Rulers - my pet peeve
08/01/2011 12:34:27
Hi guys
     Remember that when using standards to set measuring equipment that whatever you are setting is only accurate at the size of your standard, you are relying on the inherent accuracy of the tool thereafter. If you have the use of a set of slip gauges then you can check across the range of the tool you are trying to set. If you then find you have an error then I would suggest that you balance the error over the range of the tool.
i.e. set it so that it is accurate at the midway point.
Thread: Boring a Cylinder
06/01/2011 09:48:58
Hugh
   Do not put a reamer anywhere near the bore of a cylinder. A reamer is a sizing tool and is not meant to produce the sort of finish required on a cylinder bore.Secondly  as has been stated when drilling, the tool will have a tendency to snatch(in this case the reamer) this will cause minute flats within the bore, you may not even see them by eye. The end result can be a hole that looks like a 50p piece. To reduce the the potential of a tappered bore make sure the lathe is adjusted properly (no slack in any gib) reduce the overhang of the boring bar, making sure the topslide is withdrawn, and most important set the tool on centre height.
Thread: Late delivery of magazines due to adverse weather
24/12/2010 12:46:06
I am afraid it is not only you subscribers that are suffering. I, like many others try to support our local shops and order the magazines through them. I still have not received the latest M.E. and the last one was two weeks late. The newsagent blames the distributor. I had contemplated a subscription but in view of the posts here I will hold fire before I make any kind of decision.
Thread: Making a large internal lap for one off job?
20/12/2010 21:31:51
I take it this casting is cast iron, if this is the case why lap it? The danger with lapping is that particles of the lapping paste will embed themselves into the cast iron. I hope you see where I am going with this?. You will turn the head casting into an outside lap and the spindle will wear, more to the point the harder the spindle the more it will wear.
 I would use a hone (Polly sell them) this if used properly will give you a nice figure of eight finish which will hold the oil. This in turn will prolong the life of the head and spindle. If you do decide to lap, the lap must be of a softer material than the component being lapped. You must make sure that every last speck of lapping compound is removed from the casting, not an easy task especially with cast iron and its porous nature. Lapping has its uses, but to my mind this is not one of them.

Edited By Dusty on 20/12/2010 21:32:51

Thread: Chinese lathes
22/11/2010 20:41:33
Din 8606 is the standard for machine tools of normal accuracy (what is normal accuracy you might ask)  I suspect,but do not know, that it is less than the standard we would normally expect of a' toolroom' lathe. A toolroom lathe is only a lathe that is capable of maintained accuracy, most of our lathes are capable of the same sort of accuracy but require much tweeking to maintain it.
Thread: CT 918 - any comments
21/11/2010 23:54:30
Some of the earlier '918s' had a huge 4 jaw. This was basically a heavy faceplate with four radial groves in the face these had a slot in them which accepted the jaws which were loose. The jaws were secured by a stud which passed through the slot and were secured by a nut at the back. If the lathe has one it would be worth buying just for that. I missed mine when I changed lathes a while back. I could hold things in it that I am unable to in my current 4 jaw although it is a larger lathe I have now.
Thread: steel for cylinders?
21/11/2010 18:00:51
Peter
   In answer to your original query, steel as a cylinder liner in a steam loco is a no no. You will suffer with severe rusting problems, and a compatable material for the piston will also be a problem, as has already been mentioned differential expansion will rear its ugly head. My opinion is that the work involved in fitting gunmetal liners is not worth the agravation. My current loco has cylinders of slightly larger size than that of the Darjeeling. They are of cast iron with cast iron pistons, they have two iron piston rings in each piston. The cylinders were honed as Ray has indicated in his article. When tried on air I needed 50psi to get the thing moving, after a few minutes the pressure was lowered and after 15 mins the chassis ticked over on 5psi. I did make sure that plenty of engine oil (car) was introduced during this period. When the front cover was removed I had a beautiful bore in the cylinder. My advice stick with the cast iron.
21/11/2010 10:12:32
Aaaaargh   ads over posts yet again. it is so frustrating when you have to guess what has
been written. I would have thought that it would/should have been sorted out by now.

Edited By Dusty on 21/11/2010 10:13:20

Thread: O rings
06/11/2010 21:35:23
Wolfie
   If you are going to use 'O' rings you do not need a threaded gland. You are much better off using a plain gland. It appears that you have threaded the cylinder cover. This will need to be set up and bored concentric with the hole for the piston rod. If it is not concentric the 'O' ring will not work properly. New glands will need to be made with a spigot that fits the newly bored hole in the cylinder cover. The hole in the gland should be a good sliding fit on the piston rod, if you make it with clearance the 'O' ring will try to escape through the gap causing the 'O' ring to tear (yes even though it may only be a few thou gap)  The counterbore and the gland must be made so that the gap left between the bottom of the counterbore and the end of the gland is such that it allows the 'O' ring to roll a few thou. Charts can be obtained showing the nomenclature of 'O' ring groves and recesses. Your problem with the piston rod binding is probably caused by using a die to cut the thread on the gland. It is very difficult (if not impossible) to retain concentricity using a die. Either screwcut or make a new gland but do not drill it for the piston rod yet. When you have got your gland threaded, put a short length of brass in the chuck face it,drill and tap a hole the same size as the thread on you gland, make sure you can screw the gland right in. Now you can drill and ream for your piston rod. unscrew it and you will have a gland which may not be perfect but will be a lot better as far as concentricity is concerned.
Thread: warco mill help needed
02/11/2010 09:04:37
Hi Ed
      I totally agree with Bogs, an E.R. system has a number of advantages, and as he rightly states you can use them in the lathe. I invested in an E.R. 32 system some time ago and have never regreted it.  It is up to you now and how much you can afford, if you are considering using them in the lathe make sure your lathe is capable of holding them. An E.R. 32 system would be much to big for a 2 1/2" centre height lathe.
01/11/2010 19:23:28
Ed
  It would help us to help you, if we knew which Warco machine you are talking about. Is it new or previously loved? I personally do not know of a Warco mill/drill that does not have some sort of adjustment to the head. I have a Warco minor(no longer available)
I can get the spindle nose to within 3" of the table when at the lowest point on the column and around 15" at the highest. So you see with 4" travel on the quill I can reach the table. If you are thinking of purchasing a posilock type milling chuck can I enjoin you to buy both metric and imperial collets, it works out cheaper in the long run.
01/11/2010 09:01:13
Hi Ed
     I think that your problem will be solved by lowering the head. Most of these mill/drills have on the right hand side of the head two clamp bolts. Slacken these and the head can be lowered by use of the handle on the left hand side of the head. The other thing is if you are using M.T. collets in the nose of the machine you are losing about 4". The easiest way  round this is to purchase a proper milling chuck and collets(about £80) this will give far better security for your milling cutters anyway. The other alternative is a an E.R. collet set up. The 3mt collets may have seemed a cheap option at the time but as we have all found to our cost saving a few quid can cost dearly in the long run.
Hope this helps    Dusty
Thread: Tool tips
19/10/2010 16:48:52
Gentlemen
         What we are talking about is finish,nothing more nothing less. If your tool is a couple of thou over or under centre height it matters not one jot as long as you are achieving an acceptable finish. Yes, generally a tool on centre height will perform best, but how the tool is ground also has an effect on the finish you achieve.
Thread: Holding for sawing
12/10/2010 17:07:14
Many thanks guys
           Job done, I used David's idea. I was able to put a 8mm blind tapped hole in the spare bit and then clamp that to the angle plate. I will stick all the other ideas into the back of my head for future reference,allways relying on my memory not having another senior moment.
11/10/2010 15:58:24
Thanks David
              Why are things blindingly obvious when someone points them out. I think that sometimes we get to close to the job in hand, it's like when you put something down on the bench and you go to pick it up two minutes later  it has disapeared, you spend ages looking for it someone else comes along you tell them what you have 'lost' and they find it straight away, exactly where you had left it on the bench.
11/10/2010 15:26:20
I have a 1 1/2" length of 4" dia B.M.S. I need to cut a 3/4" slice from this. My bandsaw will not hold it as the length is to short. My power of lateral thinking seems to have deserted me, short of going to the gym for 6 months to build my muscles up and then hacksawing it (which is not going to happen) I have no ideas. The option is turning the blank to thickness but that would be a waste of a large piece of metal. Ideas guys?
Thread: Stuart compound marine engine
05/10/2010 09:10:28
Hi Richard
     I may be able to help you I will 'pm' you.
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