Member postings for Paul Kemp

Well generally for what Ron is trying to achieve you need a bit of oversize or undersize somewhere if a shaft is going to enter and be free running in a hole. If your reamer makes the hole exactly 16mm and the shaft is exactly 16mm then a decent running fit is unlikely. Professional reamers are made in a variety of tolerances to allow for this, the general hobby reamer will make a hole with a little clearance in which a shaft of the nominal size will run. Remember oil takes up space too so it's always good to leave a bit for it to do its job. Size for size is not a good free running fit. If you want to make the hole and shaft a press fit then you really have to look at tolerances. For general running fits a general purpose reamer is fine. I have just made a 1 1/8" hole into which I need to press fit / shrink fit a bush. I used a standard machine reamer for the hole as an easy, quick way of making a hole that is basically round with a good finish, saved setting up the boring head. I will put the interference on the OD of the bush when I turn it after measuring the hole.

Paul.

At risk of provoking a man with a moderators hat on and a big key in hand I would like to respond on behalf of the nay sayers and pessimists.

My contribution to this thread was solely based on a reason you quote - the thought for the hobby level folk and more particularly the new hobby level folk. There have been a few people join up here in the last few years and three of which have from very little knowledge or facilities turned out some very decent work and more importantly displayed independent thought and I have complimented all three gentlemen on what they have achieved. Sadly it seems all too common that a beginner asks a basic question and very quickly becomes overloaded with safety advice, theory and standards of accuracy way in excess of what is required for the job in hand. I tried to inject some humour into this thread rather than rubbish the concept outright but the truth is the OP question was about speed and that had been answered and it was heading again into theory and accuracy territory. There is nothing wrong with working to fine tolerance or expounding theory where it is necessary but there seems to be a culture on this forum that rather than encourage beginners and answer simple questions simply, information and standards have to be introduced way over the top of the simple answer required. As skills develop so will the questions and that is the time to bring in the deeper thought.

i could counter to the sarcasm accusation that expounding wisdom beyond the need is also a means of "showing off". Let us not discourage those just starting out or those asking simple questions by bombarding them with information that to the task in hand is largely irrelevant is my simple point.

If it was my post that offended you then I apologise unreservedly with the exception of asking you consider the above.

Paul.

I have to strongly disagree here. It is absolutely critical to producing a precision knurl that properly matches the standard fingerprint profile to ensure optimum grip of the knob being knurled that the diameters and knurl pitch are properly calculated to a minimum of four decimal places. Furthermore no knurl so should ever leave the shop without full inspection on a shadow graph and final verification of the major and minor diameters with a tenths micrometer.

Actually though I think there are far too many people with far too much time on their hands to even be considering this aspect of knurling. Sadly I suppose that includes me for even bothering to post on this subject!

Paul.

Like Hopper I am intrigued by the actual function of these "needles" within the printing press. Depending on their actual purpose the material spec can differ widely. If they are merely to guide paper or are used to transfer ink there may not be a requirement for them to be hard or 'strong'. Can you elaborate a little as to the actual function within the press?

Paul.

I have not built a Minnie but looking at the thickness it should be quite easy to pull that round by hand. Technique I have used for similar parts in the past is to set two round pins vertical in the vice, say a couple of bits of half inch round bar for that job, just over 1/16" apart, put the plate between them and gently curve round by pulling it and checking against the smokebox as you go. I have made tyres this way from 1/8" and thicker quite satisfactorily. You might want to clamp it on to a filed plate edge on in the middle though if you silver solder the bracket on though as it's likely to change shape when you heat it!

Paul.

I don't think I have ever seen a magnetic chuck used for milling, only grinding. I don't think I would be at all confident using one on a mill to do anything but very light work and managing the swarf would surely be a problem?

Paul.

Well it seems the flange in question is non standard. Indeed a DIN 225 does exist and it has 12 off holes but only 16mm on a 195 PCD and the spigot diameter is different also. So once again there are established standards but it doesn't mean they are used! The unit in question carries Class approval as well so it obviously doesn't matter to them either! Also seems the only way to view the complete DIN standards is to pay!

Thanks for the suggestions though.

Paul.

Dave,

Once again as pointed out by SOD it really depends what you intend doing with it. Bearing in mind the size of the lathe and the likelihood of taking 50 thou cuts I doubt the extra 10mm of the HBM and its chunkier construction perhaps greater clamping power will make a great deal of difference on your machine. If you are intending to do big stuff - I have been turning castings on the ML7 that will only just fit in the machine, but they are for a 6" scale traction engine and I have access to bigger and heavier machines to do the really big stuff. Like choosing lathes or mills it's really horses for courses in choosing work holding devices.

Paul.

Ron,

As Jason says horn plates are normally rivetted, in fact on FS engines they are often an upward extension of the firebox sides and the centre 'rivets' you see are actually the knocked up ends of the boiler stays, the ones around the edges being the rivets holding the boiler plates together. On models it is normal to have a small number of screwed fixings (6 or 8 per side) and button head Allen screws are good for that, the socket can be filled after fitting if you wish and the rest are dummy rivets. I am pretty sure some of the kit manufacturers just advocate loctiteing plain shank round head rivets in suitable clearance holes. With yours being cold this would be fine.

Paul.

Stick some kind of smooth reference bar in the chuck (bit of silver steel perhaps or a bit of 1/2" bright bar) stick a clock on the tool post and wind your slide, do it with the clock horizontal (on the side of the bar) and vertical (on top of the bar) that will show you what if any movement you have. Rough and ready way of checking it before you look further at tool geometry / height.

Paul.

Ok, age not an issue it is brand new not yet delivered from the factory. Manufacturer really not that important or relevant to the original question I think, I just want to find out if the flange of the sizes mentioned matches any established standard. Yes I am well aware of Classification Societies, their rules and approvals process, it won't be of any particular concern to them that the flange may be an odd ball as long as it can be shown by calculation and testing it meets their requirements. Unit in this case can be DNV approved for appropriate fee.

Had another dig around on the DIn website (Michael G provided a link also) and searching "marine shafts" gives a fair number of links, most interestingly enough seem to be referenced back to SAE standards. I found one I think may be relavent but they want to charge me 32 euro's to read it. Shan't be bothering with that as its not that critical! Been in the marine industry 40 odd years and never come up against this before. I will ask around my peers and if I find an answer I will let you all know.

Thanks,

Paul.

Dave, OK, did that but didn't find any specific reference to DIN standards? Do you have a direct link to a page that answers the question? I had a good dig round, they certainly have a lot of info on there, even downloaded their coupling catalogue but it's all for servo motors and torque limiters. I just need to know a DIN 225 coupling will fit the output flange we have! Can't believe this has turned out to be so difficult! Going to have to phone a friend I think!

Paul.

Mike, did that too, found loads of stuff and nice pictures and companies touting to make them but no standard! I have in the past found SAE standard flanges with tabulated dimensions against the various SAE numbers but I can't find anything for DIN on shaft couplings - plenty on pipes though! I never did rate the Germans!

Paul.

Thanks Michael, yes I had seen that and interestingly the DIN 200 does have 12 X 22mm bolts. As Jason says though, no register / spigot for alignment. I am just amazed that a search for something you would think would be so common yields such a load of dross that is nowhere near what you want!

Paul.

Thanks Michael. I have located DIN standard flanges including a 225 (which apparently relates to the diameter of the flange and not the actual DIN std No) that has a matching spigot diameter but only has 8 off 16mm bolt holes. I can't find anything that explains the mechanism for determining flange size, spigot and bolt holes etc for power transmission flanges or a table giving standard dimensions for the relevant options.

Paul.

It's a marine gearbox transmitting 900HP. I am pretty sure it's not SAE, that is the usual standard for bell housings and flywheels in this application and unlikely to be BS.

Paul.

This question has no relation to model engineering but I am sure someone on here will know the answer!

I am trying to confirm that the output flange from a Danish produced gearbox conforms to a standard! It has an OD of 225mm and thickness of 25mm, a male spigot of 145mm diameter 5mm high and 12 bolt holes 22.5mm dia on a 190mm PCD.

One commercial source suggests this is a DIN 225 flange but another says it is non standard. Google is no help whatsoever in either delivering a clear set of dimensions for DIN standard power transmission flanges only directing me to manufacturers of shafts where this size does not seem to appear or pipe flange standards which also appear not to conform.

So can anyone tell me what standard this flange may be? Apart from telling me to contact the manufacturer of the gearbox who insist on just sending me a drawing of the flange but failing to comment on any standard! Which leads me to believe it isn't standard and source B is correct although as the gearbox has classification approvals surprises me somewhat.

Thanks,

Paul.

Under the old HSE produced code of practice developed out of a document called TN3 from the federations it was recommended that anti tip rails were used. This COP is no longer supported or endorsed by HSE and in it's absence the federations are in process of releasing a new guidance document. However the draft that I saw from memory made no specific judgement such as "you shall" in favour of listing all the relevant legislation and leaving you to make up your own mind. Not seen a final version yet but to me it was nowhere as useful or pragmatic as the old HSE COP.

As far as I am aware there is no specific law applicable to anti tip rails but there is the legal precedent of "duty of care". For example if there is an injury accident on your track that doesn't have tip rails can you demonstrate you have properly fulfilled your duty of care? It may be as stated by a pervious poster that your passenger car foot boards are so close to the ground the car cannot tip over in which case in all probability you could say you don't need them. You also need to be careful your track is not considered by the local authority to be a fair ground ride, if it is it must have regular independent inspections to verify its safety and properly documented maintenance and operational checks of your own!

Final consideration is if it all goes wrong have you done enough to satisfy your insurer that they will back you and pay out on any claim. As it stands it's really down to you to demonstrate by risk assesment that you have managed any risk of derailment or tipping properly and your passengers are protected and if subsequently it is proved you haven't - watch out cos claims are us will be knocking on your door. Also worth remembering if it is decided HSE has jurisdiction (ie work was involved and it doesn't have to be paid) you could be prosecuted.

So whether you have to have them or not, it's probably a good idea to cover your bottom.

Paul.

Ron,

As I mentioned I think when you were looking for the first RT try and pick one where the locking / clamping arrangement pulls the table down on the base rather than with a screw that goes in on the side as if there is any play it will jack the table over when you lock it. Good move to get the tailstock too, always useful and a four jaw is a lot more versatile than a three jaw, you can overcome any inaccuracies in location of chuck to table by clocking the work in a four jaw, with a three jaw you are stuck with what you have and it doesn't take long to clock something true in a four jaw once you have had a little practice! Also a four jaw gives a better grip on round stock that a three jaw and allows irregular shaped work. So out of choice the 4 jaw is a lot more versatile if on a budget. You may well find though the standard plate set for the divisions you still don't have the numbers you need but worry not, you can make your own as long as you are not fussed about microns of a division!

Paul.

Derek,

Lokking good, nice to see you are progressing. Usually with glands or flanges I drill off the gland / flange tapping size for the studs, put it in position and drill through and tap, means the holes are all in the right place and the studs stand up like soldiers rather than drunken sailors! In your case though pointed or transfer studs are a good way to do it. Any way that you come up with that works is a good way to do something!

Paul.