My little engine (continued)

[GarryCParticipant @garryc]

Hi Jason

Thanks, I've had to have a look at one of 'Toms Techniques' to see how a radius corner cutter works… **LINK** – for anyone interested, it looks really useful..

I definitely need to have a go at milling around the gland and chest like your photos shows as it would be so much easier and a much better job once it feels comfortable – I'll have to think of what I can use to have a practice on and definitely try it that way for my next engine – my vertex vice is a swivel type and I have the Rotary table..

I'll include a small radius cutter when I get my new cutters..

Cheers

Garry

[JasonBModerator @jasonb]

Garry, its a radius corner cutter not a corner rounding cutter – convex cutter corner rather than concave which leaves a nice fillet where the boss meets the flat of the chest. You can buy them but I just freehand grind one from a blunt cutter, does not have to be spot on as the average of the 3 or 4 corners will give as good a curve as the sand casting.

Best way is to mount the vice ontop of the rotary table, centre on teh valve rod and do the two sides and then centre on each stud hole to do the ends.

This sequence shows a badly cast boss being cleaned up, bit harder than your chest as it was on the side of a round cylinder head.

Similar thing on teh round boss

And this thread shows how I form the shape of the gland, note I prefer the more tangental shape. But the more eliptical ones are not too hard to do

[GarryCParticipant @garryc]

Hi Jason

Thanks that took a while to go in for some reason, but I have it now – I've exported this and your build link page as pdf's to refer to when I come to do it and I've now found cutters with the right radius, I couldn't see any at ARC though – I'll have to have a think while I'm away whether to try it live on my current gland..!

and I need to check and see if my vice will fit on the rotary table…

Cheers thats going to be a bit of an essential technique to learn I think..

Garry

Edited By Garry_C on 15/09/2015 17:07:20

[GarryCParticipant @garryc]

Hi Jason

I'm hoping you may see this – I think I'll have a go at tidying around the Steam Chest boss with a radius corner cutter as you suggested and thought I'd order one so that it will be here when we get back, I was thinking of a 2mm radius and wondered what you thought as I've never used one before..

something like this perhaps (2mm radius) **LINK**

I thought I'll see what the gland looks like as it is now after doing the radius and stay with that if poss for this engine and then change over to doing both the boss and gland's on the mill in future….

I think my Vertex vice is going to be too big for my RT but I have a cheap cross vice that may well fit and do for shaping parts that can be held and maybe be easier to use for changing the centering….worth a try anyway until I get a better one. I think one mistake I made was getting a RT with 3 and not 4 T Slots…

Thanks

Cheers

Garry

Edited By Garry_C on 16/09/2015 08:15:57

Edited By Garry_C on 16/09/2015 08:17:12

[JasonBModerator @jasonb]

It could be done with that but its actually a ball nose cutter, at 4mm dia it is likely to flex away from teh work too much and with only 8mm long flutes may come up a bit short.

Give me a few mins and I'll take a photo of what I use

[JasonBModerator @jasonb]

Just roughly freehand ground on a bench grinder from blunt cutters, A quick look only shows carbide ones for sale in my catalogues which work out a bit pricy. Something like 10mm dia with a 2mm radius would be about right.

[GarryCParticipant @garryc]

Thats great thanks a lot Jason – I should have some blunt cutters that I hope I haven't binned so I'll have a go at grinding one, if not then its a good time to order new better quality ones and try and grind one of the old ones….

edit: – I swear that I'll never throw anything away again – just looked and can't find any old blunt milling cutters.. So I've ordered this to try before grinding any others (trying to make them last a bit longer before replacing), Hopefully just nibbling away with it will do the job and no great loss if not…. http://www.amazon.co.uk/gp/product/B00EZ78H18?psc=1&redirect=true&ref_=ox_sc_act_title_1&smid=A50DZI580G3JX

Cheers

Garry

Edited By Garry_C on 16/09/2015 09:12:00

[David Clark 13Participant @davidclark13]

Try using some diamond honing stones to put the radius on. Arc Euro Trade sell some plastic backed ones.

[GarryCParticipant @garryc]

Thanks David, I'll be getting my new cutters from ARC as they have been highly recommended – I'll order a stone as well. Meantime I hope the 6mm shank cutter I've ordered will do the job (slightly larger diameter shank than the first one I found) if I go at it lightly – i couldn't find a small radius one with a 10mm or thereabouts shank unless looking at high end expensive ones..

Cheers

Garry

Edited By Garry_C on 16/09/2015 10:20:03

Edited By Garry_C on 16/09/2015 10:20:22

[JasonBModerator @jasonb]

You can always do most of it with a straight cutter and then just change to the rounded one for the lastt bit.

[David Clark 13Participant @davidclark13]

Hi Gary It is easy to stone the radius on. A little bit of practice and take a trial cut on something soft like brass or aluminium to check radius for rubbing and correct size.

[GarryCParticipant @garryc]

Thats sounds like a good way to go about it Jason will do, and David I can see that's going to be a useful technique to have a go at, bound to come in handy, I'll have a box full of 'old' cutters to modify as and when soon as well…!

Trouble is now I'll not only be looking at types of nuts and bolts and threads in photo's of old engines and that – but on joining corners, fillets and such like now as well – what next I wonder

Hoping i'm bound to find a 'steam museum' (or two) in Cornwall somewhere while we're there (that allow dogs in)…

Thanks both

Garry

[Bob Brown 1Participant @bobbrown1]

I've used ball nose cutters to put a radius on parts even a 25mm one to radius some 6082 aluminium.

[JasonBModerator @jasonb]

The reason I suggested a radius corner cutter rather than a ball nose is that they can take off far more material per pass and are generally stiffer.

 

Take this piece below, 1.5mm radius to the internal fillets, the lug sticks up 9.5mm and a fair amount of metal to remove all round. I took full depth cuts using 9.5mm of the cutter length and fed in 0.050" per pass.

To do that with a ball nose cutter would have meant one of 3mm dia, how many passes would that have taken and thats if the flutes even reached down 9.5mm. Any significant stepover would leave a series of "U" shaped grooves on the surface due to the small dia of the cutter, all I did was give it a quick rum over with a garryflex block after machining.

Edited By JasonB on 16/09/2015 13:19:59

[Bob Brown 1Participant @bobbrown1]

Jason,

I suppose to some extent it depends on the radius and I have used both ball nose and a corner radius cutters, the problem of depth can be a problem dependant on how much depth there is even for square end mills when restricted by size.

[GarryCParticipant @garryc]

Not only are the fillets in those photos very nice Jason but also the 'brushed' look, if that would be the right word for it is superb. I've just been looking at some info about garryflex blocks (never heard of them until now). I'm thinking I'll have to give them a go on my next engine… I'm guessing to leave the finish like that they would need some kind of clear protective lacquer to prevent rusting, assuming that's steel in the photo's…

and I'm seeing fillets everywhere I look now – its just never sunk in what a massive difference they make…!

Cheers

Garry

[JasonBModerator @jasonb]

Yes bob job in hand will also have alarge influence on what cutter/s suit.

Garry thats Aluminium so no rust.

There is another way to do the fillets as well

[GarryCParticipant @garryc]

Thanks Jason, great to see that, I'll have to get some 'Bondo' and some 'JB Weld ' – I seem to recognise the 'filling material' used as similar to your paint prep of the Gade build…

I've learnt some cracking things on here last day or so….

Cheers

Garry

Edited By Garry_C on 16/09/2015 17:43:02

Edited By Garry_C on 16/09/2015 17:44:11

[GarryCParticipant @garryc]

I'm back I'm afraid – I see there have been some changes and i now seem to have my thread in the wrong place, I don't know how to move it and don't really want to split it again so I'll just let it die if its a problem – no worries my fault for taking so long over getting it done..!

I decided to have a go at milling the Steam Chest Gland and Boss as one. Not made a very good job of it so far as I haven't cut down low enough I think, but its looking better than it was and I have to remember its a first attempt…

Couldn't resist putting up this pic of the photo that greeted us over the main fireplace of the Cornish Cottage we stayed in, felt right at home…

Setting up to Mill the gland..

The new Milling Cutter.

Progress so far.. I haven't touched the rounded ends yet.. (the step looks a lot worse in the photo than the real thing..)

Cheers

Garry

[JasonBModerator @jasonb]

Thread is still in the same (right) place, good to see you are back at it.

J

[Mike BondarczukParticipant @mikebondarczuk27171]

Great to see you back on with the project. Like your progress and approach.

Mike

[GarryCParticipant @garryc]

Ok, thats good to hear I must have misread that, thanks Jason – and cheers Mike.

[GarryCParticipant @garryc]

Have to put today's session down to experience gained – in finishing off milling the gland, and I think it was very good experience although I guess looking at the photo's it won't look like it..

All going reasonably well rounding off the first end but then after changing tools a few times for centring on the RT I used my first 0 setting for the maximum depth on end two which of course was very silly by then… Thankfully its pretty much out of sight on the bottom of the engine, but that's not the point of course..

The overall setup used..

So to get things symmetrical I did the same on the first end – I don't think it will look too bad when it is painted – trying to convince myself it may even look better….maybe not.! It looks worse in the close up photo but the one above looks a bit more real and a lot less noticeable…

Have to learn somehow.

I should also say it was great fun doing it and definitely the way to do them in the future – hopefully will get better with them after more practice…

Cheers

Garry

Edited By Garry_C on 11/10/2015 10:18:47

Edited By Garry_C on 11/10/2015 10:19:36

[GarryCParticipant @garryc]

The Steam Inlet and Exhaust Flanges next, also the fitting hole in the steam Chest for the Displacement Lubricator..

Inlet on the left and exhaust on the right in the drawings below.

Just writing thread data here to refer to as I was getting confused…

3/8" x 26tpi – BSB Thread (British Standard Brass) – Tapping Size 8.5mm

1/2" x 26tpi – BSB Thread (British Standard Brass) – Tapping Size 11.5mm

1/4 x 32 – ME Thread (Model Engineer) – Tapping Size 5.5mm (Displacement Lubricator)

Cheers

Garry

Edited By Garry_C on 13/10/2015 05:02:10

[JasonBModerator @jasonb]

Garry if you don't have the taps already and are mostly going to be running on air you might want to make the inlet 1/8" BSP and the outlet 1/4" BSP. Both just a fraction larger OD but easier to hook the compressor upto.

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