High Pressure Steam Table Engine

[ettingtonliam]

Did you think about mounting it between centres instead of the light grip in the chuck and letting the workpiece flex?

[Jo]

If you noticed the first photo of the piece showed it on a centre but when I added the drive dog I found it was hit by the milling machine chuck at the closest end. The three jaw chuck has a fraction more clearance 

Jo

[Jasonb]

Jo, do you have a spin indexer as there is less chance of miscalculating the turns. Every other hole of the usual 36divisions would work out well

Or go for 20 flutes which is just two full turns of the div head handwheel

[Admiral_dk]

Many ways to skin the proverbial Feline .... and the Extra Spare looks fine 

Per

[Jo]

Jo, do you have a spin indexer as there is less chance of miscalculating the turns.

 

 I recall selling you my spin indexer as I didn't use it.   

Jo

[Jasonb]

Unlike you to only have one of something

I thought I had seen you using an indexer but hay have been a vertical one. Do none of your dividing heads have a direct indexing facility, I know some do.

If your cutter is getting a bit close to the chuck/collet then a simple extension could be made, just a bit of bar with a hole in it and grub screw to clamp onto the column's spigot

[Jo]

All of my dividing heads have the ability to do indexing: The standard indexing ring count is 24, which allows you to do 2, 3, 4, 6, 8, 12 and 24 divisions. Of course the columns need 18 flutes to keep me on my toes.

Thankfully the cutter and its tool holder has plenty of clearance for cutting these flutes Out of interest that little ball end cutter is an FC3 cutter and Clarkson do a rather nice FC3 cutter holder which provides a bit of an extension that can be used if needed. Personally I prefer the DA holders which are much smaller than the Clarkson ones. You may have seen me using the DA extensions on other pieces, they can be picked up for about £5 each and often come with a free collet  .

Jo

[Jasonb]

That's not a bad flute length for an FC-2 cutter, I'm moving away from them now as the carbide ones can be picked up for not much difference in cost from the likes of APT and they tend to all have 50mm overall length so reach and visibility is better, smaller sizes tend to have 4mm shank not 6mm and you can also get them with 4 flute so feed rate can be doubled.

I've seen the Clarkson adaptors but not had need to use them as I don't use a Clarkson chuck.

[Jo]

Standard milling cutters are just under 50mm long. The FC3's were always considered to be cheap disposable items, with good edges that held well and were forgiving, normally they turn up at about £1 each in their sealed packets. I have a very scary to use 1.5mm ball nosed milling cutter in carbide, as you know small carbide breaks easily 

Here are a pair of standard Clarkson FC3 holders (metric and an imperilous one  ) they fit into any tool holder that is also able to hold the same size Clarkson milling cutter. You can also see an FC3 cutter made for my BCA.

Back to flute cutting 

Jo

[john mills]

Hi   jo
Is the ball nose in the first picture a carbide end mill  it has long ftute length  the ones i used to use were very short and a 3mm shank
held them in a mazak  chuck in a er 11 chuck could run at 3500 rpm to cut a groove part way round  piston rings insides to 400mm dia
it was just as well it was in teflon compound materials or they would have been very fragile  that long flute don't know how that would have lasted.
John

[Jo]

Hi John,

Yes it is. I think high speed, well supported and cutting plastic would be increase its life expectancy before it goes "twang"


One column fluted.... just getting focused ready to do the next one 

Jo

[Jo]

Initially I started with a cut 0.2mm deep:



I repeated at 0.35mm deep:



It is really difficult to see how deep the scallops are 



So I took it to 0.4mm deep and called it deep enough. A few coffee breaks to aid my counting on the dividing head: move sector arm to touch back of plunger, move the plunger to sector arm, plus one turn, plus second turn and let the plunger go into hole. Cut next slot. Move sector arm, move plunger up to arm, 1, 2, cut. Making sure that both full turns are done (this time  )

Those horrible cutter marks will be cleaned up with a round needle file when I feel the need for something easy to do 



That's enough excitement for today 

Jo

[crueby]

Thats a LOT of cranking, counting, moving....   

[Jasonb]

Certainly an improvement on the supplied castings

Will you attempt to reuse the capitals or cut new from stock? Expect you will keep the bases due to the shape of the cut out

[Kim]

Very nice fluted columns, Jo! 

Kim