Here is a list of all the postings JasonB has made in our forums. Click on a thread name to jump to the thread.
|Thread: Water pump dimensions|
You only need to look at photos of other engines to see what the offset is, look at teh gear behind the eccentric, no way is it offset by 1/2"
Yes Jeff, altered it now
Drawing says ream 3/8" and shows ram as 3/8".
1" stroke does sound too much for that engine, he did use 1" stroke for the larger horizontal pump but 1/2" stroke eg 1/4" offset is more likely. By comparrison my 2" Fowler is 3/8" bore x 3/8" stroke.
Edited By JasonB on 20/08/2019 20:41:07
|Thread: Profiling tools|
Does say "box of 5" and around £4 a go would be right for reasonable quality. You could also try APT who will sell you a box with just two inserts of a slightly better quality.
Can't say that I use my one of these cutters very much but do use grooving & profiling type with the 2mm dia end more.
A lot will also depend on material both type and diameter. Brass cuts easily but if too slender the cutting tool will deflect it and more chance of chatter. Stick out can also be an issue when clearance for the ball turner means the work is a long way out of the chuck.
Your 75mm figure would be if the whole insert were touching, at the most only half will be in contact so 37.5mm and even then as you get further around the tool the depth of cut lessens to nothing.
This form tool probably had a contact length of 30mm on my 280, stock is 16mm square
Biggest issue using a round insert as shown in teh video is the large fillet you are left with where the ball joins the stock which becomes proportionally greater as ball diameter decreases and the wide cutting action of the "blunt" round tip will put more load on the work needing a larger dia contact with the parent stock, an RCGT rather than a RCMT would help a bit as the edge is sharper as would going down to a 5mm dia insert to reduce fillet dia and contact length.
Edited By JasonB on 20/08/2019 07:26:24
You do not need to post any more to place adverts.
|Thread: Lathe rigidity|
Check the bearing preload if you have not done it since fitting the new bearings and carry out the test on a warmed up machine.
Also take a consistant depth cut along the whole bar to eliminate changes in work, tool and spindle deflection
|Thread: Southworth engines / pumps|
Yes should be able to get them from Blackgates though I know someone who has been waiting a while for them to get some of the Lincoln range cast, not sure about pumps and the corliss.
See page 94 & 95 here
Edited By JasonB on 19/08/2019 18:20:45
|Thread: Subscription renewal notice|
You get access to all the old MEWs for the duration of the digital subscription from No1 to current and it works on Windows.
Your subs expire 1st Nov so a few weeks notice is given.
Edited By JasonB on 19/08/2019 17:26:05
|Thread: Home Workshop Site|
Thank's for the update Ketan, I have copied your post to Homeworkshop website where the subject was raised a couple of weeks ago and I responded then with the info you had already given me.
Edited By JasonB on 19/08/2019 16:57:00
|Thread: Using the faceplate and dog on a Sherline lathe|
One point that may have been missed is that when using a soft ctr held in the 3-jaw you true it up by taking a skim cut and then DO NOT remove it from the chuck until all work between ctrs is complete. By turning it before use you remove any errors that may have been there if the chuck runs slightly off and this can be more accurate than using a ctr in the spindle's Morse taper as that could be slightly off too.
That crankshaft I use to illustrate my first reply was taken in and out of the lathe several times as well as being swapped end for end but as I did not take the ctr out of the chuck all my turning will be concentric
Yes for slender parts that don't really need a lot of support you would not have to go right in with the drill and could stop part way up the 60deg part of the drill but you do need to go in past the smaller diameter pilot hole so that your ctr is bearing on a matching angled hole.
If the bar is too big to put through the lathe's spindle then yes a fixed steady or rest is used, this is one in action on something a bit bigger. You can also face the end of the bar with a setup like this as it is not good practice to start a ctr drill on a sawn end. Note as this was for a tool I have cut a small recess and then put the ctr drilled hole into that which saves the hole getting damaged which could throw things off.
Faceplates are more often used to hold odd shaped work that won't easily fir a 3 or 4 jaw chuck.
A drive or catch plate is a lot shorter than a 3-jaw chuck so allows you to get the max distance between ctrs as it does not protrude beyond the ctr mounted directly in the spindle
Edited By JasonB on 19/08/2019 13:16:28
Size depends on the work in hand but for a small lathe like that a BS-0 or BS-1 should be about all you need. For very fine work it is often a case of "picking up" the centre with a graver.
Work would be held in a chuck or collet with most insid ethe lathe spindle, if too big for the spindle then the free end would be supported with a fixed steady for drilling. or you can simply mark out the ends and drill with a bench drill.
For your Staff you would not drill holes but use female ctrs that the shaped ends fit into.
This photo from yesterday shows what NDIY is saying, a soft ctr turned to a point in te hchuck and the cranked dog being driven by the chuck jaw.
Edited By JasonB on 19/08/2019 12:27:33
Edited By JasonB on 19/08/2019 13:16:46
|Thread: The Workshop Progress Thread 2019|
That's Right Ron, some models tend to use upturned cap heads screws but I put a fine straight knurl on some 4mm steel and then reduced turned the end down for a M2.5 thread before using a 3mm ball mm nose cutter to make the recess. I'll be making all my own period fixings, the cap heads are just easy during construction.
The reason these engines did not have a throttle was they often went into tether boats where you had no control of the engine just dropped the boat into the water running and timed it to see how fast it could complete a set number of loops, at this sort of period they were getting around 50mph out of the top ones.
Michael, the whole of the old magazines make interesting reading as they cover many subject and the adverts are as interesting or more so than the articles. Page 626 of the 1936 edition has the article about making the castings.
The fuel tank turned up today along with some spares so that jamjar Maytag engine could be a possibility. I'm sure the postie must think I'm getting into jam making as I also bought some 8oz Mason jars for another engines vapour tank.
|Thread: Kingscale 5" models|
I assume these engines need a steam test before you can go an run them anywhere just like any other newly built loco?
|Thread: The Workshop Progress Thread 2019|
Thank's Ron, I think it was that video that first got me thinking of making the engine so I got the 1938 Practical Mechanics Shop notes that had both of the two part article in them. One shows the patterns to make your own castings and the other the construction.
I have scaled it down from 1 1/4" bore to 24mm and altered just about every part in some way but still kept to the basic layout and overall look. As you noted the simple rockers and bent wire pushrods are a bit basic so I have some shapely rockers ( see the KX£ adventure thread) with screw adjusters and the tappets ride in bronze bearings. I will deviate a bit on the carb which is just a plain venturi type on the original by adding a throttle and doing something a bit nicer than the metal pot seen in the video for the fuel tank. As the engine is just for show being able to blip the throttle will be more enjoyable than having it just running flat out and also save it getting too hot while stationary.
Although several illustrations show the engine in a boat hull this one is an interesting use for it and if Michael G. is looking in he will approve of the tool being used. Also shows the basic rocker and rod design.
Edited By JasonB on 19/08/2019 07:35:56
|Thread: Part built Allchin 1.5 inch|
Most of the ME suppliers who sell steam fittings will do packs of washers in nixed thicknesses. Reeves do them in various diameters here
|Thread: Grinding your own lathe cutters|
Thank's for that Michael. I was thinking of asking whet the part looked like.
Are the "trumpet" shaped ends critical or would a taper do? As I said in the thread about radius tools a graver would more than likely have been used and for those trumpet shapes and the undercut it would be the best tool for the job as I can't see it being done with off the shelf brazed tooling or inserts for that matter though you may get close with a RCGT one.
|Thread: Digital inclinometers|
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