Paddleducks
Other Marine Models => Live steam => Topic started by: smuttley on November 18, 2008, 05:45:45 PM
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Can anyone point me too a forum post that explains how and what tool to cut say 2mm wide by 2mm deep grooves in a cylinder head for cooling fins?
Thanks in advance,
Regards
Steve
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Hi PD's....Steve ...best spend a few hours in the WEB site
Th engine cylinder heads are best left as 'heat sink common'.........& certainly can/should be insulated
The cooling fins you talk about are the increased surface area on steam lubricators .....to condense the oily water/steam oil condensate
Welcome to our PD site ...........Derek
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Hi Steve,
If you have a lathe, you could use a parting tool. If you do it by hand, hacksaw blades stacked together will do it.
Regards,
Gerald
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Steve,
grooves in a cylinder head for cooling fins?
You haven't told us whether they should be around the head or cylinder, or across the head, as in over the top.
Both have different techniques involved.
I gather you don't have a mill, but do you have a vertical slide for the lathe? I ask this because really, over the top finning is usually a milling operation, and really needs either of the above bits of kit to get consistent results.
John
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I have a lathe, but as bogstandard mentioned, I have no milling machine yet. I was after cutting fins in a cylinder or round stock for practice, as I have not been machining for long and trying different methods of cutting, for the day when I build my fist engine or two. I have a HSS parting tool, but anything other than soft metals is hard going. Just wondered how other do it and pick some tips up.
No vertical slide yet John, but the wife says she is going to get me one for Christmas (I hope).
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Steve,
Because you are a total newbie to machining, I don't know if you know how to set the correct tool height, so the first crap-o-cad sketch shows the method that I teach to beginners. Tool height is one of the most critical setups you need to do, get it wrong and you will hit all sorts of problems.
The line on the sketch is in fact a strip of metal, I use an old six inch rule. Gently trap the strip between the tool tip and the workpiece, then look from the end. By comparing what you see with the sketch shows what you need to do. Once the strip is vertical, you are close enough on centre height, and you should have no machining problems on the height score.
Cutting finning grooves.
Start simple, no fancy stuff, just get a nice even row of fins, equally spaced.
Look at the second sketch, the top shows what you want to achieve. Select yourself a relatively soft material to practice on, brass, aluminium or nylon. No steel for the moment, start simple and build up to the difficult stuff.
You will need to grind yourself up a grooving tool. For shallow depth cuts, the one I have shown is perfectly good enough, you don't need the tip tapered front to back yet, parallel sides will do OK. Make sure you put the top rake and front rake on, something near is close enough for now. Also ensure that the tip is square to the sides, not angled.
The easy way now is once you have set the tool to the correct height and square to the job is to wind your topslide fully back and ensure it is lined up at 0 on the degree scale. Then using the saddle fwds/back and crossfeed get the tool to touch the end of the job as shown. Lock your saddle so that it cannot move side to side then carry out the numbered sequence, feeding sideways using the topslide.
For about 3/4" bar, a speed of around 400 to 500 rpm should be OK, if using a soft metal a little squirt of WD40 will help with the cutting action, more so if aluminium is used.
Practice is the only way to do this exercise. Once you can get good results doing it like I have said, then you can progress onto more complicated tool shapes and materials.
I am not being patronising, but until you can get the basics under your belt, you shouldn't take too big a step. It is better to have a lot of little successes rather than one massive failure.
Just take everything steadily and logically and all of a sudden, things will start to fall into place.
Hope this has helped.
John
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John,
Your a genius, your method for finding centre is fantastically simple and effective. I am working at the moment, but as soon as I can get back in to the shed, I will give it a shot,
Thanks again,
Steve
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Steve,
Not a genius at all, just passing on information I have picked up along my journey.
With regards to tool height. Derek brought to my attention thru PM that really the tool should be set a couple of thou below centre, and of course he is perfectly correct. But at this time, rather than confuse the issue, setting spot on will be fine. It all depends on how beefy the toolpost is and the size of cutter. Someone like myself who has a very rigid machine and rather large cutters (16mm) would need to set that lower cutter, but it is now readily accepted, with lighter machines and smaller cutters, the tip will be deflected downwards by the action of the cut.
It is this phenomenon of tool deflection that causes most of the problems of chatter marks on smaller 'hobby' type machines when taking heavier cuts. So playing around slightly with tool heights (only very small settings) and keeping the tool tip as close to the toolpost as possible might eradicate some of the problems.
John
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Hi PD's.....bogstandard also suggested in a PM that these newer .......assumed as 'cemented carbide' triangular bits that have 3 cutting faces on one side ....then three faces on the obverse ....or reverse.........tips may not be as crisp+sharp as a home ground HSS tool piece....& hence the issue of 'Tool Pressure' ...........to attain a certain result.. :hammer
Whilst John acknowledges my old :hehe training........I am totally lost with the concept of these new THINGIES ....in the tool post...of my planned lathe/mill combo unit of the future :porkies.... Derek
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The 'cemented carbide' triangular bits are primary used in large industrial machines (high horsepower, massive and rigged), ether manual or more likely CNC. The type of machines most of us acquire do not have the HP or rigidity to use them as intended, and quite often a properly sharpened HSS bit will out perform them for the type of work we do.
Regards,
Gerald
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Gerald,
I couldn't agree with you more.
Here is an article I did for a machine retailers site, the third post, in reply to the second, shows my real opinions on tungsten tooling, and the problems encountered with it in the modern day.
http://www.atfreeforum.com/chesteruk/viewtopic.php?t=315&mforum=chesteruk
It seemed to have touched the spot, as the chappie never replied.
John
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Looks like I have a lot of reading to do.
Here is a pic of the type of tool I am using.
(http://www.farmtrader.com.au/13257.jpg)
I have a left and right cutter and a boring bar only at present, all 12mm to suit my tool holder. They are not cheap to buy at around AU$250 with ten tips. As a NEWBIE I have already come to the conclusion, that the most important part of lathe work is a correctly set up machine, second to this is the cutting tool, not only using the correct tool, but the danger involved in using them incorrectly. I have grate respect for anything moving and flying in my direction.
I have not broken a tip yet, as I am going very, very slowly (shallow cuts), this maybe a problem as I may not be cutting deep enough for the type of tip I am using and at the correct speed. I do feel that my lathe is underpowered at times and labours with harder metals, when this happens I back the tool off and take smaller cuts, and again this could be wrong.
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One of the problems with the 'cemented carbide' triangular bits is they do not handle interrupted cuts too well. I do use them (I also use HSS), and most of the ones I have chipped have been on either interrupted cuts or intermittent cooling (another thing they don't like).
Regards,
Gerald
PS John,
I can't agree more your posts in the link. I think you should copy them and have Eddy put them in a sticky.
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Hi PD's....& this is a good learning thread......but :thinking..Steve ....you still have not mentioned why you want to provide cooling fins on an engine cylinder that should be kept at an optimal constant hot temperature
The steam exiting the model boiler is in the order of 150 degrees C [without superheat] & we lag the boiler to engine steam line to attempt to maintain the highest steam temperature to the engine for firstly ......engine rotation but also expansion of steam to do work.... which naturally reduces the temperature of the steam [this expansion of steam is sort of like FREE energy..but if we do not harness it ....it is wasted] .....Derek
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......but :thinking..Steve ....you still have not mentioned why you want to provide cooling fins on an engine cylinder that should be kept at an optimal constant hot temperature
Sorry Derek,
I did mention further up the thread that I wanted to practise small grove cutting in cylinders or round stock. Not for cooling steam (changing phase), just for decoration of say support pillars. I will be building other engines besides steam, hopefully build petrol, compressed air and Stirling engines etc. I was more after the technique of how others do this.
I must mention that I work in a very large refinery in Western Australia, part of my job is to look after the steam distribution lines, steam trapping, condensate recovery systems and shell and tube heaters, we consume over 650 Tonnes per hour from our own power station for heating our process. My expertise is in condensate induced water hammer, eliminating this and educating others of it's dangers. As you say, cooling steam is the last thing one would want to do, other than de-superheating down to or near steam saturation temperature for heating.
I have for a long time wanted to build my own steam engines, as I am fascinated by the stuff,
Regards
Steve
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OK PD's.....& Steve has explained a few things here....but a few questions for our more qualified members :shhh
I remember :shoot
1) for HSS we used al/oxide wheels & try to not let the stock get beyond STRAW colour prior to quenching
2) for tungsten carbide inserts we used a silicon carbide wheel + water cooling
30 years later ....walking around the machine shop I see many of these triangular cemented carbide inserts waiting for the rubish bin....could these not be re surfaced via a silicon carbide wheel + water cooling? or is this just a THROW away engineering society? ...
I have priced these tips for home use & @ AUD$9.00 per insert & divided by 6 = $1.50 per cutting face...which is still good $ value
A 10x10 mm x 80 mm long HSS shank in OZ is $7.00 ....see what I mean :crash
It seems that the HSS tool grinding processes we were taught 30 years ago....back rake, fore rake, chip rake etc .......are all near a thing of the past :coffee Derek
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OK PD's ...for the second time this evening
1) have reread to comments from Steve...looks like a periodontal error on my part. :shoot...sorry.....any person responsible for 650 tonnes of steam condensate/hour is looking after a BIG number of units...is it all PLC controlled?
2) stick with PD's Steve... & after twenty postings or so ........you may open your own FOLDER in Steam & comment on the Boyles & Charles Laws of Gas Equation's..... :hehe :towel
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Derek,
for tungsten carbide inserts we used a silicon carbide wheel + water cooling
I think we are getting slightly confused here. Green grit wheels are used for brazed carbide tipped tools, not for cemented carbide tip inserts.
Inserts are generally considered disposable once they have been chipped or dulled by use. Certain types can be resurfaced, and I do it myself, but really needs a diamond impregnated wheel or flat laps, with water as the lubricant.
I actually sharpen some new ones before use to allow me to do much finer turning work on difficult materials.
I think you will find, the old flat triangular six tipped ones are starting to go out of fashion. The types being used now come with toprake and front rake ready moulded in, but are usually single sided.
There is no comparison between tips and HSS tool bars. The HSS last many times longer than the tungsten tips. I have a favourite HSS tool that I have been grinding and touching up for a few years. In the UK I can get a length of HSS tooling for the same price as one cemented carbide tip.
http://www.arceurotrade.co.uk/Catalogue/Cutting-Tools/High-Speed-Steel-Toolbits
http://rdgtools.co.uk/acatalog/TIPS1_FOR_INDEXABLE_TOOLS.html
As I stated in the article on the other site, for most work done by model engineers, HSS toolbits will be a lot more effective than carbide.
John
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1) have reread to comments from Steve...looks like a periodontal error on my part. :shoot...sorry.....any person responsible for 650 tonnes of steam condensate/hour is looking after a BIG number of units...is it all PLC controlled?
2) stick with PD's Steve... & after twenty postings or so ........you may open your own FOLDER in Steam & comment on the Boyles & Charles Laws of Gas Equation's..... :hehe :towel
(http://www.titusinformationsystems.com/MAIN/bpx-one.jpg)
No PLC's Derek, refineries of any size use something like this, main frame computer systems running controls and feed back to many central control rooms, for processing.
I think it will take a lot of skill to grind my own cutting tool, but as my machine is small, I must investigate this further. I would rather do things that suits my needs, and that is accuracy, very close tolerance and final product finish, no good building an engine and it looks like it's been turned and scratched with a pen knife,
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Hi PD's....well I think that steamboatmodel & bogstandard have sorted us out .... :hammer...just use HSS & be happy with it
Steve ...you must get the cleaners to look at those two floor tiles to the left...... :hehe...............& keep a sharp eye on those LCD display's.............regards Derek
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Steve ...you must get the cleaners to look at those two floor tiles to the left...... :hehe...............& keep a sharp eye on those LCD display's.............regards Derek
LOL :great
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Hi Steve ,
I have been following this thread a little I have a very small lathe similar to the mini lathe, I can recommend that hss tools are much better,
your indexable tool will cut very well on brass,but their use on small machines are a bit more challenging on steel,for steel say 3/4 dia I would look
for about 3 to 4 thou of feed and 1000 to 1500 rpm with a 10 thou cut,this would be my starting point.These small machines cannot do much more on a cut as it will vibrate or deflect,I usually tell people hss cuts, carbide rubs it off,normally this is true as most indexable tips have no sharp cutting edge unlike a sharp knife.try it, an indexable tip will not cut your finger like a stanley knife will.
http://www.cromwell.co.uk/KEN0100120K
you can buy hss like this,I have used these and can recomend them,it is easy to regrind them as you can just follow the original angles
but the 3/4 dia steel bar you would want about 400 rpm and use a brush with coolant on.
Regards Steven
ps if you ever come across lots of used broken indexable tips don't throw them away 1 lbs of tips will fetch i think about £10.00 scrap value.
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Hi Steve ,
I have been following this thread a little I have a very small lathe similar to the mini lathe, I can recommend that hss tools are much better,
you can buy hss like this,I have used these and can recomend them,it is easy to regrind them as you can just follow the original angles
but the 3/4 dia steel bar you would want about 400 rpm and use a brush with coolant on.
Ok, I am now getting what you guys have been trying to tell me, I did a lot of reading last night and I now understand a little more. Here is a link to my machine. https://www.machineryhouse.com.au/Products?stockCode=L148
It takes 12mm size tools and I was looking at getting a small set of pre ground, but I can only find Tungsten tipped types like this in Australia so far, https://www.machineryhouse.com.au/Products?stockCode=L008 Will they do the jobs?
I will have to do a lot more searching to find an Australian suppliers. Thanks for you help and guidance with this,
Regards
Steve
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Steve,
Now you are talking about a different type of beastie from the cemented tipped tools.
The ones you are showing are the generally available 'brazed tip' variety, and are treated and used in a totally different way. Cheap and cheerful I would describe them.
The grade of solid carbide that is used is totally different to the moulded cemented type, and these can have a very sharp edge put on them.
I use a few of this type, mainly for single point screwcutting, and if treated with respect and set up correctly can do sterling service for a model engineer.
Remember the 'set up correctly bit'. They need to be set up perfectly on centre height, any deviation, and they will chip their edges quite rapidly. Unless you go for the big industrial jobbies, they should be treated like light, very sharp versions of HSS tooling, with a capability to cope with harder materials. No heavy cuts and keep them cool and well lubricated, otherwise the brazed joint is liable to melt and the tip will fall off. They can't stand up to the rigours of replaceable tipped tooling, which sometimes I use for very hard materials and I have sparks coming from the cutting face, try it with these and you are onto a loser.
It is this type, like Derek commented on, that can be resharpened on front and side faces with a green grit wheel. The top face should be dressed with a diamond lap with water as the lubricant as the final act. One swipe across the top face with a lap can bring all edges to a razor like sharpness.
If you are going down this route, you will require an offhand grinder with a fine green grit wheel and a small 'credit card' diamond lap (very cheap nowadays) to keep them sharp. If that is the case, buy a few HSS bits as well, and practise grinding your own, but not on the green grit side, that is a very soft wheel designed for grinding very hard materials such as tungsten, but on the 'grey' wheel side that normally they come mounted with. I don't want to start quoting grades and materials for wheels as it will only confuse the issue even further, grey and green is fine for the moment, and is the standard used on most model engineering tooling sites.
http://rdgtools.co.uk/acatalog/EVERYTHING_ELSE_ABRASIVE.html
http://rdgtools.co.uk/acatalog/DIAMOND_TOOLS.html
http://rdgtools.co.uk/acatalog/TOOL_STEEL___BLANK_S_.html
http://rdgtools.co.uk/acatalog/BRAZED_LATHE_TOOLS.html
http://rdgtools.co.uk/acatalog/worldwide_shipping.html
I use these people all the time, and a lot of my American colleagues have used them for special items that aren't available in the US, and they have all said that they have received good and fast service, and very reasonable postage rates. It might be worth sending them an email to get a few quotes for those unobtainable bits and pieces.
John
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Hi Steve,
I have seen this type of tooling and I would agree with John they would need re-grinding too be of any use!.
here is a link that will help you
http://www.ameng.com.au/suppliers.htm
as always the choice of tooling is up to you,your machine is larger than mine so you may get carbide to work ok,on mini lathes it can be difficult.
but I would always advise on either hss or carbon steel tools in the beginning as they are less demanding on technique and more forgiving and will
produce good results.the hard part in todays world is not many people know how to grind them correctly and there are fewer people to "visit" and
be shown,make a good off hand grinding rest at least 3" x 4" ,there are plenty of designs on the web.I gave one away to someone who had been
modeling for many years,I ground a tool for him on his grinder and it surpassed anything he had tried but there was no grinding rest, he just did it free hand and had not got the angles correct.later on in the year I visited the individuals garden railway he showed me proudly the grinding rest and some tools he had ground.one of his words were "I wish I had,had that grinding rest 20 years ago",he is in his mid 80s ,it is a shame but this does often happen, some people don't like model engineering clubs or cannot access them and don't have access to someone that knows.
most of my tools are old myford boat types which I have collected from either shows second hand or boot sales these are only carbon steel but
will produce very good results and some will be 30+ years old and more,I just re harden and temper when i reach the end of the "hard bit".
because I am a Yorkshire man it has to be cheap and cheerful (successful).
I do have some carbide tooling but these are for use on cast iron castings as I would ruin carbon tool steel if I used them.
Regards Steven
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Thanks Guys,
Very helpful info here, I will grab some HSS and have a go at grinding my own, practise, practise and more practise,
Thanks again
Regards
Steve
:)
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For a reasonable compromise between the ease of replacing inserts and the durability of high speed steel you might consider something like this:
http://littlemachineshop.com/products/product_view.php?ProductID=1724
The are not cheap, but neither are carbide inserts. I have access to a wide variety of carbide inserts from a machine shop and frequently they are tossed with one or two unused edges. I sharpen with a diamond hone and get quite a bit of use from them.
I have one of these diamond tool holders and while they don't do any one type of cut perfectly, as would a purpose ground bit, they do many things pretty well without having to change the toolholder angle. It comes with a sharpening jig that makes sharpening very quick.
http://www.bay-com.com/index.php?main_page=index&cPath=2&zenid=b9e7b0f76909ffead7b116a4f71772b2
I feel it was well worth what I paid.
Thanx
MikeR C