What's new
What's new

Working with Ductile Iron - Making Adapter Flanges: Drilling/Tapping and 3" hole boring.

Clausing4900

Plastic
Joined
Oct 7, 2014
I am needing to create 10 adapter flanges from ductile Iron (65-45-12 Dura-Bar)
I don't deal with cast or ductile often and am limited to my Bridgeport and my 10" Clausing with a 6" 3-Jaw chuck.

First question is the surface finish in raw form. I do not plan (or have the capacity) to turn the OD down so im curious what the factory/mill finish looks like on this stock. The OD finish,diameter and concentricity are not critical, I would just like to know if it is a smooth finish or rough casting.

I plan to have 10 discs cut and shipped at 2.250" thick. Six will be at 8.250" OD the remaining four will be at 6.500" OD.

Four of the flanges will need a through hole of 2". The other 6 will need through holes at 3". Will an annular cutter handle this. I would drill a hole or two around the periphery to allow chips/swarf to fall free as evacuation may be troublesome when pushing through 2.250" of material. I do not have flood coolant available.

Next step would be facing each flange. I am not sure what method is used to cut these by the supplier but I'd imagine a bandsaw or cold saw. Most likely the faces will need trued up. I plan to grab the ID of my newly cut hole in my lathe chuck and gently face each with a Bullnose center pushed up to the rotating flange for safety.

One side of the each disc will have 6 blind tapped holes of 3/4x10 and the other side has 4 at 5/8-11 blind tapped holes, both sides tapped at 1.000" depth. Will rigid tapping/power tapping these work with a high quality spiral flute tap in this material?

Does this sound feasible; will annular cutters (2" and 3") live long enough in this material? How about the spiral flute tap?

I have a boring head for my mill if an annulalr cutter wont hack it.

Thank for any input or advice.
 

hvnlymachining

Cast Iron
Joined
Jun 21, 2019
Location
St.Onge
Dura bar is generally pretty easy to machine, the OD will resemble hot rolled steel ( mill scale) and be oversized. Most steel cutting tools can cut it just fine in small quantity, but being cast can be somewhat abrasive to cutting edges.
I machine a fair amount of cast irons and prefer ceramic insert tooling for the best surface finish.

As to facing, mine always arrives bandsaw cut. You will definitely want to square both faces of the disc. I wouldn't send one out without cleaning up the OD either, just not pretty enough for me to send out, and Durabar can be real nice when done right. As long as you're going to be mounting it by the ID already for facing, true the OD.

I don't think you're going to want to power tap 5/8" -11or 3/4"-10 in your Bridgeport, unless you don't need it for later jobs. ( May not make it through this one) those are big tools for such tiny gears.

Spiral taps don't help in cast as the chips break very short and won't evacuate as occurs in steel. But any HSS tap will cut cast just fine.

Annular should be fine, coolant is un necessary, but a shop vac is required. I often run my shop vac during machining to keep dust down and remove chips simultaneously.
 

Clausing4900

Plastic
Joined
Oct 7, 2014
Excellent information. You are correct on the OD being available to turn if chucking by the ID. These are to convert DI water fitting. The finish is terrible in very way with regards to the mating parts so appearance is not critical but wouldn't take any time to skim the scale off if already chucked up.

I had planned on employing the ol' shop vac to keep the nasty cuttings under control and clear.

I will need to get my bolt pattern positioned with my DRO and but may opt to hand tap using the quill as a guide. I was a little leery myself running those large taps under power. I've tapped hundreds of holes with same 7/16 OSG spiral point tap in mild 1018 but never anything that large, much less in ductile.

If going manual on the tapping, can the threads be cut in one pass, or is it necessary to back out to remove the chips after every few rotations?
 

hvnlymachining

Cast Iron
Joined
Jun 21, 2019
Location
St.Onge
One pass should be fine, the vac can be used during tapping to evacuate chips.

I also use the dro and do the drilling on my BP, but hand tap larger taps with a tap follower chucked up in the spindle to keep everything nice and square.
 

Clausing4900

Plastic
Joined
Oct 7, 2014
I don't think Blanchard grinding is an option if I want to keep this within budget. Sure would be nice though. I was going to have the OD and ID waterjetted out of 2" hot rolled but it really drives up the cost. These adapter flanges arent common but there is a supplier; unfortunately they're weeks out on delivery and expensive.

I considered getting a blind flange but they are not thick enough to tap from both faces in addition to the holes coming sized for through-bolts leaving no material for threads to be cut.

Thank you all for the advice.
 

atomarc

Diamond
Joined
Mar 16, 2009
Location
Eureka, CA
Wow...with a 10" lathe sporting a 6" chuck your shop rate must be minimal if you're "going to keep this within budget". That's a lot of work with a nasty, tough material for a hobby type shop. Good luck, senor!
 

john.k

Diamond
Joined
Dec 21, 2012
Location
Brisbane Qld Australia
Used to work in a foundry with nuthin but ductile iron......machine shop floor was a black sahara,you had to trudge thru iron chips to get to the kazi........your tea mug was jet black where the black dust reacted with the tannic acid ...every thing you lifted was covered in black dust......reckon I got "Black Lung " workin there......a vacuum cleaner would have got buried in the iron chips in five minutes.
 

DDoug

Diamond
Joined
Oct 18, 2005
Location
NW Pa
I don't think Blanchard grinding is an option if I want to keep this within budget. Sure would be nice though. I was going to have the OD and ID waterjetted out of 2" hot rolled but it really drives up the cost. These adapter flanges arent common but there is a supplier; unfortunately they're weeks out on delivery and expensive.

I considered getting a blind flange but they are not thick enough to tap from both faces in addition to the holes coming sized for through-bolts leaving no material for threads to be cut.

Thank you all for the advice.
Why are you making these in the first place ?
It sounds as if you've never made a simple flange before, nor tooled up to doo so.

FWIW I did plenty of these from 1" thick MS burnouts. Grab on 1/2", turn, face and bore.
Flip over, grab by slightly less than 1/2", dial in on the bore, turn the rest of the OD.
 
Last edited:

Clausing4900

Plastic
Joined
Oct 7, 2014
I figure I'll have a few days in labor to make these. This isn't my primary source of income and I often have plenty of free time. My small collection of machine tools are more to assist with my other interests and hobbies. I realize they're not ideal for this project.

I can get it done but am curious about tool life and feasibility with the anuular cutter and tapping of the some 120 holes I'll need. Will I burn up multiple cutters and taps in the process? I haven't worked with ductile enough to forecast this.

I'll be using carbide inserts for the facing operations.

I'll have my respirator on and Vac running when the dust starts flying.

Thanks
 

DDoug

Diamond
Joined
Oct 18, 2005
Location
NW Pa
Run flood coolant, clean tank when done.
The more flood the better, to sluice the grit right off the ways.
 

Mtndew

Diamond
Joined
Jun 7, 2012
Location
Michigan
Yah man it SMELLS?

Treat it the same as dead fish that smell, then.

Mount a sharp tool.
Cut off its nose.

End of problem.

Yes. Whenever our lathes are turning ductile iron, that smell gives me an instant headache. Same thing when we cut G10.
 

DDoug

Diamond
Joined
Oct 18, 2005
Location
NW Pa
Tried that.

ONCE!

"Off" was the part that didn't... ennybody have an air-chisel?

Folk say machine it dry for good reason! Damned good.
...and yet, I've run blanchard grinder for years with flood coolant on CI.
Just clean the tank out each night.
 

DDoug

Diamond
Joined
Oct 18, 2005
Location
NW Pa
C'mon, Doug?

Lathe and mill cuttings don't BEGIN to RESEMBLE grinder swarf in size NOR "self interlocking" shape?

CI don' give yah no "bird's nests".

Gets wet, it's closer to Pertified Pigeon chit, hard packed and in a hurry to fossilize!

Everbody hates it. Nobody loves it. Some would rather eat worms!

Surely can make a nice finished product, though!

Per a Merseyside-born G'mum: You have to take the bitter with the better.
Gee...someone else is using coolant on cast iron...:
 

guythatbrews

Hot Rolled
Joined
Dec 14, 2017
Location
MO, USA
We used to power tap 3/4-10 blind holes in mild steel in a Bridgeport. Spiral flute tap. It worked fine. Make a split bushing and hold the tap in a collet. Not sure of unit power requirement for mild steel vs ductile iron. Keep the minor diameter as big as you can. Wouldn't use a spiral flute tap. I'm guessing a hand tap.
 








 
Top