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Member postings for Ramon Wilson

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

Thread: Badger Mini Abrasive Gun
19/02/2010 13:39:53
Hi,
As I'm approaching the finishing ops on a couple of crankcases I was wondering if anyone has any experience of using the small Badger 'sand blaster'.
 
I am particularly thinking of using one to create a uniform surface finish on aluminium. Any info on it's suitability (or not) for  this or similar applications would be appreciated.
 
Or is there something better - but for not much more cost!
 
Thanks - Ramon
Thread: How to prepare Hot Rolled Steel for marking/machining
18/02/2010 23:28:21
John
That is a interesting comparitive and, something tells me, probably a hell of a lot cheaper too!
 
The bonus of course is the ability to use in it in the workshop without the dreaded 'plague' covering everything - and the disposal!
 
Milling 'through' scale into the metal below is not a problem but it will dull the cutter at the point of the scale - the thickness of the scale will score the cutter edges - use the cutter after to face off the end of some part and you will see it - not very big but it is there. But to remove the scale using an endmill without affecting the metal beneath - which is how it reads to me - is definitely a no no, well, not unless you have lots of cutters or conversely a deep pocket.
 
Forget about the Aldecon SJ and get off down to B&Q
 
Best of luck with your project
 
Regards - Ramon
Thread: Heat Treatment of I/C Cylinders
18/02/2010 23:06:13
Meyrick, just noticed my error  For someone who can get (mildly) irritated by a Y or D being added to my name I'm a little annoyed with myself! My apologies for spelling yours wrong in previous posts.
 
Had a look on the MEN site regarding materials for piston and liners. I think it would be fair to say that as far as cast/cast and cast /steel goes there seems to be two schools of thought fairly equally divided. There is a reference to Westbury recommending carburising cast liners though it doesn't say for which engines - whether this was his normal recommendation for all his engines I have no idea. I have a couple of his articles so will check them out.
 
Thinking about the production side a bit more possibly the non of use of cast was down to it's fragility in thin sections in machining - particulary when cutting the ports ??
 
The cases grow slowly- lots of rotary milling today but, still on course for two (so far!!) 
It will be interesting to compare both types of liner both in the machining and in the running - will take plenty of pics and keep it posted!
 
At this stage though I will keep to cast iron for the pistons, outside of ABC set ups for the size concerned many are made from this material - Perhaps ali on the next one? chromed bore and all
 
'Super Merlin' - Funnily enough just done a bore on one for a friend - and you began with R-C I see - Real Control that is - "fly by wire" - and my constant 'achilles heel' over the years. Never really was attracted to R/C power apart from the odd assisted free-flight but did fly a lot of glider for five or six years.
 
Engines - well I suppose you could say I have had quite a few!!!!!. Like yourself  Super Tigres figure highly along with OS - particulary the 35S. The most consistant running engine ever was a ST40(S?) - blue 'dished' cylinder head. Unfortunately it wasn't really suited to the demands of the aerobatic (C/L) mode of flying but it was a lovely engine. A few years back I rebuilt a ST-21/46 bought for 12 quid at a swap meet. It was in a really sorry state but had sound internals. After a fair bit of work however it proved to be the best aerobatic motor I have used. Haven't flown it since 2006 though - it still resides in the Thunderbird hanging in the garage!
 
Snow forecast for tomorrow, I shall think of  'Jomac' and get an early start 'a fettlin'
 
Regards - Ramon
 
 
Thread: How to prepare Hot Rolled Steel for marking/machining
18/02/2010 22:04:14
Hi,
 
Assuming you are refering to the mill scale as rolled and not the scale on any edges created by cutting processes I don't know if the following will be of any use to you but for what its worth -
 
There used to be  a product available from 'Jenolite' called Aldecon C.
This was used for 'etching' the surface of hardened and ground parts before using their 'Cold Black'solution. It is a very powerful agent and will remove the scale back to bright steel.
 
I did a set of frames from black rolled steel and with this plus a bit of elbow grease and some coarse emery had them looking like BMS in a day. I did them on a hot sunny day (bit of a problem at the moment!) - laid them on some thick polythene liberally coated with the (neat) stuff - wrapped them up and left them in the sun. Don't know if that improved the process - just the way I did it.. It certainly removed the scale without affecting the steel in any visually apparent manner.
 
Two things - if you do decide to try some. It contains hydrochloric acid - obviously take the usual precautions - and don't, definitely don't, leave this stuff open or use it (even if well diluted)  in the workshop as it will cover absolutely everything that is bright steel with a brown rust(?) like patina in very short order indeed.
 
Diluted it makes an extremely good pickle for silver soldered steel items taking all that black gunge off right back to the bright (though a little 'grey') steel leaving just the solder to clean up. A thorough washing in fresh water is required. A much fainter brown patina will still form though very slight and is easily removed with a bit of fine emery
 
I don't know if it's still available - I bought mine through my works along with Cold Black about ten years or so ago.
 
I don't know of any mechanical means that will remove scale (which, as you've probably already found out, can be glass hard) as well as this stuff.
 
Hope this helps to answer your question.
 
regards - Ramon
 
 
Thread: Heat Treatment of I/C Cylinders
17/02/2010 13:54:38
Hi all, the timing out only seems to be if too much time is taken writing a post. Last night after writing I scrolled up, checked I was still logged in (yes) (this was the frustrating bit)  and opened a file to copy a pic - opened 'insert image' and got  'you need to be logged in to use this function' Back up to log in and of course the text previously duly copied had been replacd by said pic  - Aaaaggghhhhh!
 
So in future it's copy text first, log out (to be sure) login again - paste text and then get pic. Well that's the theory any way.!
 
Les, as I recall certainly the early Bee had a propensity to lose it's seal fairly quickly - only a thought, based on what Merrick is saying, and thoughts on possibly losing that fit through the wearing process but could this have been why. Others - Mills actually advertised the fact - used hardened and ground cylinders. If cast is an acceptable alternative to steel it does raise the question why they would go to such lengths on a production basis. I guess we may hear more on this one.
KeilKraft hmmmm! Love 'em - My first kit too at age 11 - totally the wrong thing - Sopwith Camel- didn't even fly like a brick but it set me out on a modelling adventure that has lasted a lifetime. Great memories.
 
Had a good morning in the workshop but the sun is finally shining - oh dear - that means garden -  I sense a degree of conflict on the horizon
 
Regards for now - Ramon
 
 
Hi John glad to hear you've cooled down a bit, I have 'found' the ModelEngineNews site - early December and it is exactly as you say - spent far too much, but very enjoyable, time going through it's seemingly endless pages.
16/02/2010 23:59:04
Nice post Merrick,
 
I had just written to your previous one and yes once again the blessed thing timed out and despite having saved it I 'moved' to get a pic and lost the bl---dy lot - again !!!! God that is tiresome - and now you've upped the ante.
 
Cast iron - you paint a very good picture - you are obviously much more technically aware of these matters than myself -my fall down I guess - I'm much more a practical person. I suppose it would be fair to say my interests lay more with the actual 'doing' - the machining processes themselves (and the results) than perhaps any specific subject.
 
My closing line in my lost post was to say that there may be two (of the current project) and that I would fit one with a cast liner. (I'm doing two crank cases - if there's a booboo I won't have to go all the way back to the start again!)
 
One has to agree, that making a liner from iron would probably be a lot easier machining wise than a toughish piece of tool steel but it begs the question why have so many gone the other route - I don't recall any model aero engine (I assume we are not straying outside of this area at the moment) with a cast liner and piston though looking back to some early diesels I grant you that's possible - all the ringed engines I have had however, have been fitted with a steel liner - normally hardened and ground of course. Perhaps because of this -  I don't think its a matter of trying to re-invent the wheel - that for most, without being able to carry out cylindrical grinding, that tough steel is generally considered as the next best option.
 
I'm not disputing your description of the glazing/skin hardness properties but what kind of wear is involved before this becomes 'serviceable' - with a cast piston enough to lose the original lapped fit possibly? I don't know? Small diesels need very good piston/liner seals to start easily and function well so that soft iron/iron could- may- be detrimental to that end. I appreciate the 'cast rings in a cast liner' situation but the compression and piston seal required for such engines is much less than for a small diesel
 
There's only one way to find out  - you pays yer money etc - but I shall hedge my bets and make one of each and see how they stand up to each other. I think it will all come down to the lapping - we shall see.
 
Ramon
 

Edited By Ramon Wilson on 16/02/2010 23:59:36

16/02/2010 17:09:38
Hi Mike,
Welcome to the (first) I/C build club.
 
First thing I guess to ask is what kind of engine are you building and it's capacity and secondly what you intend to do with it once it's finished - that  is how much are you likely to run it and in what fashion?
 
Silver steel in it's 'raw' state can be a 'bitty' material to machine particularly if your liner needs a thread cut on it but of course for most people it's the most readily available and accesible form of tool steel. Wear wise depends on the running ahead but with a cast iron piston it should make a reasonable combination. 
 
As you can see from the previous posts the opinion is to leave it unhardened.
 
Regarding the internal hones I have used these to great effect but they will not  true an out of round or tapered bore - for that you will need to lap it. Again it depends on the initial machining how good a bore is but I would always lap it after machining before using the hone to 'break the surface' and apply those microscopic scratches that honing gives if it needs it. For a really good piston/liner fit then lapping the piston is also essential finally lapping it to the bore itself. The two stone variety are no where as effective as the three stone hones for trueness so that in itself limits their use depending on engine bore size my three stone goes down to 3/4" - I don't know of any others (3 stone) that go smaller.
 
I have had good success with just lapping over the years so If you need any further info  just shout.
 
Hope this helps - Ramon
 
 
Thread: Slitting saw
16/02/2010 11:58:59
All good advice so far Chris,
Merrick is quite correct of course in that the cutting speeds should be the same for the given work material and the specific cutter material - however when slitting several other factors come into play that reducing the speed and feed when first carrying out the operation makes it a much less fraught situation especially for the beginner.
That said of course one of the problems most machines have is the inability to go slow enough for the size of saw and material to be cut particularly if the saw is largish and on the harder materials. eg stainless, carbon steel or cast - The only saw available when I slotted the some Quorn castings was 6" diameter so had to make a very small drive pulley to get the speed down.
 
Saws come with lots of different tooth patterns too - some quite fine and others very coarse. Fine ones obviously make quite a lot of fine swarf and are prone to clogging if not cleared with lots of coolant and again as Merick confirms this can prove quite a messy operation - speed reduction helps here too!
 
I'm very much with Tony here though on using a cutting fluid brushed on, clearing any chips from the teeth at the same time as well as agreeing that the cut should be made in one  pass if at all possible.
 
If the saw blade is clamped securely between two flat discs then slippage should not be a problem, if it does occur however it can normally be cured effectively by interspersing a paper shim. It should be said though that, when using hand feed, it's much better to slip than having a 'fixed' drive which could shatter the saw if it does jam.
 
Ergo feeding by hand is also good advice - as said it is much easier to feel/sense what is going on as the cut continues - power feed, if you have it, is okay once the op has been established but but if the saw jams - which sods law guarantees will happen only after the hand is taken off the feed engagement lever - a 'crab up' will occur in amazingly short order!
 
Merricks last paragraph sums it up perfectly - enjoy yourself
 
Regards - Ramon
 
 
 
15/02/2010 22:12:05
Chris
The speed and feed will relate directly to the diameter of your saw, and the material you plan to cut - I assume your saws are HSS.
 
Work holding comes down very much to the job in hand. Some metals 'close' particularly if you are doing something like splitting a tubular section or ring and you should be ready for this as it can sometimes grab or nip the saw blade quite strongly as the saw breaks through.
 
Make absolutely sure you are not 'climb milling' ie the direction of travel of the work should be into the direction of travel of the teeth.
 
The normal cutting speeds for HSS tooling are usually well reduced but keep the saw cutting - don't let it rub - particularly if it's phosphor bronze or stainless but don't force it either.
Another thing to be aware of is that despite an accurate tool holder they don't always run true (on diameter) and you will hear the cut is intermittent. Don't worry too much about this unless it is excessive - just concentrate on a nice steady feed making allowance for the run out.
 
It might help a bit more if you can say what the saw diameter and thickness is and  the material and depth of cut you want to apply.
 
Hope this helps to start with -
 
Regards - Ramon
Thread: Heat Treatment of I/C Cylinders
15/02/2010 21:48:47
Thanks Jens, literally sat down to post and yours listed up.
 
The Alpha turns out to be much smaller than it looks - is this your interpretation of Richard Gordons 'Alpha' so to have a 'vintage look? If so you have captured it very well indeed.
 
All input so far points clearly to success with high tensile steel for the liner so that is what I shall use - probably the stud material as already said. I have no idea what specification this was but as it was oilfield equipment I would guess it's fairly high one.
As I recall though it was very tough to machine the threads down to the root diameter but that was in my early days as a novice model engineer. Anyway I have dug it out and will see what it machines like before I make a final decision. I do have 'one or two' bits of tough tool steels to choose from as well as some nice 'continuous cast' cast iron lumps to make pistons from. All scrounged and squirrelled away for that 'rainy' day!! I guess one day I really will miss going to work!
 
I have made a quite few pistons in the past and lapped and fitted them to the cylinders of  worn engines. I don't know if anyone else has done this but a cast iron piston can be made to 'grow' if heated to a 'cherry red' and left to cool. Several well worn diesels and glows have been reclaimed this way, the average model aircraft engine piston growing about a thou/thou and a half depending on diameter. More than enough to re-size using an external lap and then lapping to fit the bore. it dosn't seem to affect the properties of the iron and the engines done like this appear to last just as before. Unfortunately though you can only do this just the once, so if you over do the lapping it its 'make a new piston' time!
 
John I can only sympathise with your plight as I simply cannot begin to imagine what trying to endure 40 degrees on a daily basis must be like let alone try to enjoy some time in the workshop. I hope you solve your shade problems and get back in there as soon as you are able. Tomorrow when my feet are a bit cold ishall remind myself that it could be a lot worse!.
 
The milling progresses on the crankcases - more a bit later - if they turn out okay that is!
 
Thanks again, regards - Ramon
 
 

Edited By Ramon Wilson on 15/02/2010 22:15:43

15/02/2010 00:05:54

Thank you for your replies, your interest is much appreciated
Can I just say - as I don't want to mislead anyone - that I have 'messed' around with model engines - mainly aircraft, a few marine - since  the age of fourteen so am quite conversant with their attributes and make up - within those environments. Having said that I count myself as no expert, just reasonably knowledgeable about the basics.
 
Over the latter years of this period  various 'bits and pieces' for many engines have been made - rebores, new pistons, crank bearings, changed the timing etc. mainly for control line aerobatic use and to a minor extent, lower level racing.
 
Until the Nova engine though I had never made a complete engine so that's a ''first' and as this has proved reasonably successful I thought it would be good to continue on the same road.
 
The engine is based on the 2.46 cc ED Racer, but 'scaled' to 5cc capacity and whilst there is no intention to get the absolute maximum revs and power out of it, I would hopefully expect that it will turn say a 9 x 6 prop around the 10,000 mark. It certainly won't be used 'in anger' so to speak so given that it will only get the occasional run I can see from your advice that there will be little point in going down the heat treatment route. I was looking at this possiblity purely as an 'extension' to the building process.
 
Jens advice on using high tensile steel and Windy's confirmation of it's durability under competition use is recommendation enough and that is what I shall use in conjunction with a cast iron piston. Somewhere in the depths of my metal box there are two lengths of very high tensile steel, turned from  foot long studs, 'surplus to requirements' from offshore days. After near half a lifetime under the bench I guess it's time to actually use some of it!
 
I believe the taper In ABC engines is there to allow the piston and liner to reach optimum fit at the top end when running, the brass liner expanding more than the aluminium piston. One reason why ABC engines should never be run-in in the same manner as lapped pistons in a cast iron or steel bore ie slow rich runs- much better for these to be of short duration but high reving - taking care not to let the engine overheat. To my knowledge I don't think ABC (model) engines are fitted with rings - may be wrong but never heard of it in the sizes I'm used to.
 
Thanks again for your input, I would still like to hear from anyone who may have heat treated a liner, but for this build, I shall certainly be following the advice offered
 
Regards - Ramon
 
 PS Jens, What is the engine in your avatar please?
 
 
 
 

Edited By Ramon Wilson on 15/02/2010 00:10:05

Edited By Ramon Wilson on 15/02/2010 00:12:27

14/02/2010 19:00:04
Hi,
 
I've just begun milling the crankcase on my new I/C project, a scaled up (twice capacity) version of a model aircraft diesel engine of my youth.
 
Whilst doing so I have been musing on whether or not to harden the cylinder.
 
I have, under controlled conditions at work, heat treated literaly hundreds of small parts though none were cylindrical - that is 'tubular'.
 
Well aware of the distortion that can take place if parts are not quenched carefully I wonder if anyone has experience of this application in a home workshop environment.
 
I was thinking of using tool steel, specifically B01Arne and  tempering well back.  I have no means to grind this but  suppose I could  make a spindle that would allow this op to be done on the lathe though I really don't want to go down this road because of potential contamination. I was thinking more that I may be able to lap any distortion out providing this could be kept to a minimum.
 
The other option is carburising but I have little experience of this. I do have plenty of Casenite but am put off by the amount of time under heat this requires for a good depth of hardness and the distortion prospects when this is quenched in clear cold water.
 
I could of course just use a piece of  tough-ish tool steel and leave it unhardened.
 
Anyone have any thoughts on this - would appreciate it if you have .
 
Regards - Ramon
PS This got ate once - apologies if it posts twice.
 
Thread: Boring Question
11/02/2010 21:38:46
Yes "I can see clearly now" what you mean - it was that first image of Mikes plus the fact that I was visualising the tool being held vertically in both planes. The article in the sample issue gives all and as I do have some 1/4 square HSS and plenty of steel  theres no excuse. Back on this one (sooner, rather than) later!
 
My thanks again guys - Ramon
11/02/2010 18:58:42
What a lovely bunch of chaps you are.
 
Thanks a lot for your posts. I've studied Mikes pictures (thanks for your offer Mike) and can see what needs doing so will check out the freebie article too. I see that the tool needs to be trapezoidal (spelling?) so I guess these are available - I think that now I really will regret not having access to all those grinders - just think of the bits that could have been made in a lunch hour! One of the chaps I worked with does have a 540 so perhaps if I offer to do the holders he will do the tool bits???
 
Careful now Merrick - you're weakening   Personally I've never found the quality lacking on FC3, but I know what you mean about the monkey metal though. We had a buyer who thought she knew better - Clarkson ordered - ended up with such a cheap alternative that 16mm end mills could be 'sharpened' with a file - honestly! Totally unhardened. They were 'nice and shiny' though and above all of course "they cost much less" - 'we' won that one though ! Happy days
 
Thanks again - Ramon
11/02/2010 14:43:22
Ah, now you are talking about real machining
 
I'd like to try this type of tool - are there any drawings for a home built version?
 
regards - Ramon
 
PS Don't overdose on the coolant
Thread: Turbine Blades
11/02/2010 14:30:48
James, with your initial question and your last comment in mind ......
 
All the above replies have been good suggestions and may be the answer  to your needs however  "How do you mill a propeller without CNC kit?"
 
Not an easy problem to solve with basic kit - I have no actual practical experience with the following suggestion though do understand the principles involved.
 
I'm sure you are aware that (for a constant pitch) the angle of a prop blade changes (lessens) as the radius increases toward the tip. To create this effect then the workpiece would have to be rotated as the cutter travelled along the blade in effect - spiral milling. Outside of NC this would require that the rotary device, either a rotary table set horizontally or a dividing head be connected in some way to the leadscrew movement. The latter is quite normal set up on a universal mill but probably not in the average ME's kit.
 
Having given it a bit of thought - IF - the rotary device could be disengaged ie to freewheel and the workpiece held securely then the rotary device could be made to rotate as the table moves by a bar emanating from the side of the (moving part) table. If this bar was to bear on a  fixed triangular plate (or be captive in an angular slot) that is securely held but independant of the table travel the bar would slide up the slope rotating the table as the cutter advances along. This obviously would be some set up and the cuts would need to be gingerly applied but it would give the effect that you seek. Whether it would actually do the job you require is another question. In effect the same priciple as dis-engaging the cross slide leadscrew for taper turning, just different axiis.(How do  you spell that?) The angle off the triangular plate would give you the pitch transition you seek - the actual pitch angle to start would have to be set on the workpiece. It would need to be set up so that the cutting forces if possible acted such to keep the bar in contact - I would see this as very much using the side of the cutter - all a bit pricarious to say the least not to mention backlash but that's the principle. This would give you flat sectioned blades the camber is down to hand work .
Should you decide to go this route I would try it on something very soft first - plastic or wood to prove it all out. The 'maths' involved - well I'll leave that to you - or others -definitely not my best subject! - Just don't forget the pics!!!
 
Whilst I concur that KWIL definitely has a point I hope this might go some way to answer your original question.
 
Now, back for that afternoon session
 
Regards - Ramon
 
 
Thread: Boring Question
11/02/2010 09:39:20
Yes Merrick, very rarely venture into the top range unless it's something really tiny.
 
Coolant is a problem with tips very much a case of all or nothing. Ian's right the Haas machine pumped it out at some 14 gallons a minute if I remember right - three outlets simply throwing it on. Because of this need (and the ability to contain it) all carbide tools - lathe or conventional mills - were used dry. Blue chips and stand well back! I expect there are quite a few reading this will remember having the odd hot blue spiral smack them on the cheek and stick just under the glasses.!
I remember the uncoated Seco tips well, they were always preferred for the Clarkson Hi-Flo milling cutters and on the lathe for mild steel - they always outlasted other types.
Because of the way they were used I have never felt the desire to strain the Myford and the mill simply isn't up to it. Hence their limited use at home.
 
Just going back to the 'Throw - Away' FC3 bits a moment
I totally agree about the need to get up to a shoulder and /or face off but I don't use them for that - the whole object, and the point I was trying to make was that they require very little grinding (from solid) and are ideal for making small cutters for odd jobs -  very small parting off, tiny bores, o-ring grooves, screwcutting tools ad infinitum. Once the FC3 cutters are of no further use on the mill, if a cut off wheel isn't available then a quick nick on the edge of a grinding wheel at the start of the flutes,  the flutes held in a vice, and covered with a bit of rag before snapping off with a hammer. Ergo free 6mm or 1/4 round HSS.
Putting the need to turn to a deep shoulder aside - I tried this from fresh the other day - straight forward left-hand turning tool - 12mins for 5/16 square HSS and  just over 2 for the insert. It's not so much the time but the dust and heat build up. I accept the HSS insert won't get as deep or as close as the 5/16 blank nor will that get as deep as the carbide tooling, but they are very useful when you need something quick to advoid having to grind relatively much bigger lumps of HSS. It's offered purely as a help to those
whose budget might be slightly 'restrained' as well as being a good way to use something otherwise 'thrown away'.
 
I've yet to try the Tangential tooling though I understand the principle - sharpening being very simple to achieve. I guess we all have our old habit's though. Good we're all different .
 
It's cold and miserable outside - guess I'm off to the workshop then
Have a good day in yours
Kind regards - Ramon

Edited By Ramon Wilson on 11/02/2010 09:42:49

Thread: Nova 1 compression ignition engine
10/02/2010 23:01:14
Hi again,
 
Just like to add my friend John finally finished his engine and I went over to his today for a twin run. In a word - Magic!
 
He had made a mount out of a nice piece of wood, the engines were bolted in and the flicking began. Not too good at first but we put that down to the cold - it was a bit parkie with the windows and doors open and snowing outside. Anyway finally got them running - bet his neigbours were impressed - and they performed well.
By cunning reduction of his spray bar diameter his has a much larger venturi area and was doing a consistent 5100 to mine steady at 4000 - his has a nicer beat too so having chided him for already 'tuning it up' it's a now question of 'if you can't beat 'em' etc.'
 It was a good end to a short, very enjoyable project - on to the next? You bet.
 
Thanks for all your interest on this one back with another I/C soon
 
Regards - Ramon

PS Often taken for brothers I've known John since I was four years old - I'm the good looking one with the white beard!
 

 
Thread: diamond grinding wheels
10/02/2010 22:28:36
 
Hi All, Some good replies here. At the risk of repeating myself a bit perhaps I should elaborate a little.
As said diamond wheels were only used as far as I remember for surface grinding the cutting faces of punches and dies. Most of these P&D's had very complex shapes the forms of which were wire eroded. The use of diamond wheels was purely down to the hardness of carbide. Prior to the accelerated use of carbides in these press tools  these parts were made from varying grades of tool steel and whilst the more complex were wire eroded many were formed by grinding with conventional wheels. The forms were shaped on the wheels by a single point diamond using an 'Optidress' wheel forming attachment.( Big panic when you hooked the diamond out of the end of the dressing 'stick' !) The forms took many different shapes of angles and radii all dressed in this way. To give an idea of the limits of dressing involved it was frequently required to dress a 1/4 wide 6" wheel down to a thin blade with a .8mm (yes that is right) radius on the end. (That form had to be 'dropped in' some 16mm which required an awful lot of re-dressing as the wheel glazed up) Sorry for repeating myself - the wheels came in all sorts of grades, bonds and hardness to allow this to be carried out. I mention this to give you some idea of the (relative) ease of which conventional abrasive wheels can be shaped - not to suggest you do it - or even need to do it - at home but if you have a T&C then this is going to be a lot more beneficial to expose new clean grit than not being able to shape a diamond wheel.
 
Merrick is right to say these are finishing ops or to put it another way if you do intend to cut from solid - eg HSS blank for turning - then you need to take your time. Grinding is not something that can be forced. I don't wish to raise the dreaded H&S but be aware that grinding wheels are not shatterproof and do rotate at a peripheral speed that will shower lumps of abrasive everywhere at a phenomenal rate of knots - it makes a big bang and you don't get an advance warning! Sorry if it sounds like a lecture but it has to be said - Keep your wheel guards on. Really!  And whilst we're on the matter its not good to beathe the dust created when grinding carbide particularly if you use a diamond. The dust, once in the lungs, does not come out and it's accumulative. I know the amount that the home user is likely to be exposed too is very small, probably very very small - but it's a health issue that you should really be aware of.
 
Finally can I just remind you this was ten years ago - the progress since then particularly in the use of carbides and wire eroding has made these techniques very much a thing of the past. Things have moved on - I just haven't so don't beat me up if I'm off the mark!!
 
Thanks for the info on the diamond dresser - I couldn't open the pics on the link but the price was much better than anticipated. This is the type I mentioned, I guess the Chronos one will be similar, as you can see it's on it's last legs so it's good to know I can replace it.
Hope this helps a bit more
Regards - Ramon
 

Edited By Ramon Wilson on 10/02/2010 22:32:28

09/02/2010 23:55:37
As I've said it's quite some time since I was involved with these matters but unless things have changed this was how it was -
 
Our press tools were made up of individual parts made of hardened (various) tool steels or carbide. The diamond wheels were only used on the carbide and never on the steels. I was not involved with the carbides but I recollect the wheel was brought down on a 'block' of some material which trued the wheel and removed any detritus.
 
The tool steels were ground with a myriad of wheels - sorry but I can't remember all the grits and grades but most were white for form ginding ranging from soft to very hard, brown 46J for basic surfacing and/or roughing, pink for the really hard chrome steels. These wheels were all dressed regularly with a diamond held rigidly in a holder on the chuck or in the optidress wheel grinding attachment. All well to the rear of the technology queue now I guess but it may have relevance.
 
All of our diamonds were 'single point' of varying carats but someone at some time gave me a very small piece of diamond impregnated steel section about 12 x 6mm. This is bolted to a piece of steel for a crude handle. I have no idea what it is called or where to get it from but it is absolutely the best thing for hand dressing abrasive wheels - as the steel grinds away fresh diamonds are exposed - I used it only at the weekend to trim the wheels on the off hand. I'll take a pic of it tomorrow so you can see what I mean.
It's getting rather short - if you know where I can get another I'd be grateful
 
Hope this helps -  Ramon
Regards - Ramon
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