Member postings for Paul Kemp

Mark,

As always the amount you can plough off not only depends on the machine but also the set up / arrangement for work holding. With a lump of steel in the vice I generally take between 0.030" and 0.050" cuts with a 2" 4 insert face mill in the vertical spindle, if not clamped quite so rigidly then less. Earlier this year I had to cut a 3/4" slot through cast iron again about 0.050" bites with a 3/4" end mill, probably would have taken twice that easilly but I wasn't in a rush, it was clamped to a large angle plate and didn't want to risk screwing up the casting to find out. I have also used up to 1" dia drills in the quill. I cut the full set of gears for my half size traction engine (cast iron blanks) 4DP so 0.530" (from memory) tooth depth in one pass, biggest gear was @19" diameter on the horizontal spindle with no particular issues, just a conservative feed rate. I don't think I would take 1/4" cuts with a slab mill, it's an "industrial" machine but a relatively small one!. Others have questioned rigidity of the vertical head and made additional support brackets to tie it to the horizontal over arm but to date I have had no reason to need to do that. Attraction for me is the versatility, you can reposition the vertical spindle to get anywhere over the table and being able to tilt it made drilling the steam ports in the cylinder casting a doddle.

Paul.

James,

All above answers correct. Some other considerations for you though depending on how you plan to cut the thread. If you measure commercially made fastenings depending on the tolerance and thread engagement you will find they have a major diameter slightly smaller than nominal.

if you are going to screw cut then starting with the full nominal is a good idea as your depth will be related to that. If you are going to use a split circular die then being a few thou under the nominal won't hurt as there will be a degree of extrusion in the die cutting process and it will be easier to cut.

Paul.

Paul,

I struggled big time to make the whistle that came with the bits for my 4" RP whistle! Read loads of stuff on net which to be honest wasn't very helpful or consistent! Edge of the bell on mine is square and ended up with an annular gap of less than 5 thou. The gap seemed to be the critical bit! Profile of the edge of the bell and vertical height of bell above the base much less important. A decent deep tone depends on size of the bell.

Paul.

Me too Andrew! I have only been doing this metal bashing lark for 45 years and I still can't get a mirror finish on everything I make. I must be using the wrong tooling or not grinding it proper.

Paul.

Well I have two hynyaung (or however you spell it) Chinese inverters running my mill for about 14 months now and they have been absolutely fine, no complaints whatsoever. The set up wasn't difficult, plenty of info available on the web to assist in 'interpreting' the manual. There was one parameter that was troublesome but with some excellent support from here I managed to sort it without any drama. For my application it was around 1/3 of the cost of using the UK based suppliers to achieve the same result going this way and as the total cost at the time was a barrier to get the machine running the longevity wasn't a major consideration. For the work the machine has done I don't consider they owe me much and even if they pack up now (which they probably will now I have written this!) I won't be overly upset. As things stand I wouldn't hesitate to go the same route again. The only caution I would sound is buying direct from China and having them ship from there, my first attempt at that didn't go well! On the second try I used a UK based seller and they were with me in three days, cost me a little more but worth it to save a 5 week sea freight delivery and import duty etc. Overall very happy!

Paul.

Well I use em, I don't have any issues. Have a set of 16mm that I use on the big lathes I have access too (Edgewick, Holbrook and Harrison), some 8mm ones I use on the hobbymat at home and occasionally on the myford. Out of the 16mm set I don't think there is any I haven't used although perhaps not for their intended purpose! Ie the parting tool has been ground into a long reach threading tool and a couple of the others 'butchered' to strange shapes to suit difficult access areas on some iron castings. That said I also use HSS and indexable tips on all the machines. I have a 1" square long boring bar (home made) that uses round HSS bits. Tend to use whatever will work the best for whatever job is being done or whatever is the most cost effective way of getting decent cuts. Can't really understand why people get hung up on one particular tooling type, they all have advantages and disadvantages, why limit yourself? I also save the blunt or chipped indexable tips and if I need something obscure braze em on to a bit of bar and free hand grind them, handy for custom bars for the boring heads. Sometimes I will rough out with a tipped tool and then finish with HSS. Only indexable tips I have never used I think are screw cutting tips, mostly I grind them from HSS although I do have and have used some brazed tip ones. I don't need to cut any micron perfect threads so my methods suit what I need to do.

Paul.

David,

You say the pump works off the engine when dunked in a shallow container. That implies the suction fitting on the pump body is direct in the water? When operating the pump like that does it develop any pressure on the outlet or are you just observing a little water being discharged? If you put your finger over the outlet when testing off the engine you can see if it is developing any pressure. You can test the delivery valve by connecting an air line (carefully) to the outlet. If the valve is good there will be no movement of the ram. You can test the suction valve by blocking or plugging the outlet, you should be able to pull the ram out on the suction stroke but not push it back in on the delivery stroke. If you can push the ram in you need to check if either the ram seal is leaking or if it is returning past the suction valve ie the suction valve is leaking. That will confirm the pump is good. Last thought is the pump of a type that has an integral bypass valve fitted in the body casting. If so as Jason said is the valve in the correct position? Picture of the pump might help. Good luck.

Paul.

Ron,

Personally I think you are over thinking the situation between pulley and bearing. Firstly the relative rotational speeds are pretty low as are the loadings. If the shaft is to be a soft (say mild steel) material then using hardened washers is likely to have them cut a groove in the shaft over time! Oilite is a bearing material and no reason to suppose that in this 'thrust' application it will be any less efficient than in the normal radial condition. Many thrust bearings are plain bronze with oil lubrication, oilite is a similar but 'self lubricating' material. Your PTFE washer is probably the kindest solution to shaft, bearing and pulley if you really want to control the axial location of the assembly. Lastly I doubt the loco will travel the distance of London to Edinburgh so whatever you do is unlikely to wear catastrophically.

is the TE on the back burner now?

Paul.

I would assume it's to preserve the fit. Every time you press something out the hole gets a teeny bit bigger. Drilling them out first reduces the bulk of material and relaxes the strength of the fit hence reducing the growth of the hole and preserving the original tolerance.

Paul.

Through a hole and pipe extension off the side, not yet drilled and fitted! Looks like it was left once the turning was completed and never finished!

Paul.

Difficult to be sure with the size of the picture but it looks like it should be a captive blow down valve. Ball goes in the shroud at the end of the spindle which gets forced onto the seat in the body when the spindle is tightened. Back nut is to stop you screwing it all the way out!

Paul.

Try driving London bound on the M2 / A2 in the morning and the opposite way in the evening! I unfortunately have to do this fairly regularly and having ridden bikes myself I still have palpitations watching the antics, get on centre white line between lanes, open throttle and try to weave between anything that may be in your path - it's worse on the multi lane sections if you are in a car at 60 (you can rarely get to 70 and more often 15 is optimistic!) but at 60 you can have the pleasure of being both undertaken and overtaken by bikes on either side between the adjacent cars - not even waiting for a gap! I have had my mirror clouted twice in the last fortnight and saw one come to grief. Maybe things are different in your neck of the woods! I rode bikes for many years and did a few track days but the way bikers behave now scares me!

Paul.

Derek,

Afraid I don't know the detail of the Alchin diff as have never built one but when making the diff on my LS I left the centre boss of the diff housing (both sides) over length from the figure quoted on the drawing. I then set it up in the lathe first one way and then the other and gently faced it back to get a nice engagement with a bit of clearance / backlash on both crown wheels to the pinions. Worth mentioning all gears in the diff on my 6" LS are cast gears (as many full size engines were) so they are not as precise as machined gears!

As I am guessing on the Alchin I would say you are on the right track with shims. Ideally you want a little bit of backlash in the diff for smooth running.

Paul.

Derek,

"small amount" of play will be fine. In practice the diff gears only really rotate when turning corners and then only a tooth or two at a time or depending on the set up if winching where they may turn proper. If you look at any full size engine gears, your small amount would translate to a brand new running fit! If you think about the age of these machines many of them are well past their sell by date in terms of gear wear but they still run just find albeit a little on the noisy side!

Paul.

William,

If you look at Arc Eurotrade web site you might just find a picture of a mill very similar to yours and if you look at the parts list you may well find they have exactly what you need sat on their shelf which for less time and probably less money they could send you, over you making your own.

Paul.

Ian,

You might want to consider fitting a bigger hand wheel to the knee, if you have a job with a lot of vertical movement you will find the small wheel hard work. The small wheel should fit on the other end of the table to give you another option for table traverse. The machines were only supplied with one table hand wheel as standard from new.

Paul.

Iain,

My baby mill is exactly the same as yours and I have suffered several failures too! First time round I split the motor gear so fitted a new one - key was slack so I filed up a new stepped key that was a good neat fit. Second failure was the gear fork breaking completely and similar damage to the gears. Replaced the lot, third time it spread like yours and of course broke when I went to straighten it - so I welded it back together! That drove all the oil out of the bushes so I soaked it for a few days, made a new longer key that spans the gears fully and off we went again. So far, it's still running! My impression is the radiused end on the short key acts like a wedge in the nylon and jacks the gears apart, bending the fork. My new key is full width of the gears and square ended so eliminates the possibility of the wedge effect. Try making your own key with the new gears rather than using the std one, I feel you will get on better! Only needs files and patience!

Paul.

Ok. Afraid I am not familiar with the device! Any chance it is configured so the gauge reads a differential preassure? That could tie in with the other contribution of often reading "considerably higher than boiler pressure" ?

Paul.

Have you checked the pressure gauge? They have been known to be wrong!

Paul.

I think to use the example of Mr Fraser to support the argument that physical punishment does not work is stretching the point a little. Sadly there will always be examples like that and I very much doubt given he was certified insane several times that the soft touch would have been any more successful! Whatever the arguments for or against hanging and similar disfiguring punishments (and I am not advocating either way) at least hanging guarantees 100% there is no chance of a re-offence by the recipient! How many cases have their been in recent history of offenders being released, supposedly assessed by professionals as rehabilitated and posing no further risk to society that have gone on the re-offend with devastating consequences for innocent individuals going about their daily business who have just been in the wrong place at the wrong time!

Using statistical data as sole evidence of the success or failure of any policy is also flawed if used in isolation who said there are lies, damn lies and statistics? Pure numerical evidence can be manipulated to convince something is so when in fact taken in conjunction with other evidence the picture is different.

If there was a true answer to the problem properly implemented there would be no problem! Fact is as highlighted by others there are many variables that contribute such as cultural belief, ethics, morals and example. As I think I said a good few post back if society instilled successfully in its peers a proper sense of right and wrong and moral conduct then the judicial system would only be needed to deal with the minority extremes like Mr Fraser and his 89 year old ASBO holding mate and in their case segregation or eradication from the masses would be the only sure fire way of preventing further mischief!

As also said by others the deterrent of respect for the law coupled with a high chance of being caught is fast disappearing in this country so expect plenty more examples like this in the future!

Paul.