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anvil surfacing

Doggggboy

Ultra Member
Neighbour has asked about me flattening one of his anvils after watching the latest Fireball Tool video.
I have John Conroy's old Ferro mill. What would be a decent cutter for something like this?
I guess I could do it with my 1/2 inch end mill but what are some better options?
 

Tom Kitta

Ultra Member
How much flattening is needed - maybe one can do few passes on surface grinder. Otherwise I go with carbide face mill with good inserts. I would not go with HSS as if it is a real anvil with hardened face HSS will die very soon.
 

John Conroy

member
Premium Member
I have a shop made flycutter that uses a carbide inserted lathe tool as the cutter. I made it using an R8 face mill holder that was not being used. I have used it out to 9 inch diameter and it is very rigid. Small depth of cut and slow spindle speed are best for flycutters. Something like this would be the least expensive tool to try first. If you want to borrow it I can send it in the mail.

 

Dusty

(Bill)
Premium Member
@John Conroy, enjoyed reading your post. When you speak to "Small depth of cut and slow spindle speed are best for flycutters." Can you be more specific on speeds and depth of cut.

How serious is the hit and miss banging at the edges?

I assume the same process would also apply to facing a rectangular item on one's lathe held by a 4 jaw?
 
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Doggggboy

Ultra Member
How much flattening is needed - maybe one can do few passes on surface grinder. Otherwise I go with carbide face mill with good inserts. I would not go with HSS as if it is a real anvil with hardened face HSS will die very soon.
Not sure. Haven't seen it yet. I'm miles away from the nearest surface grinder.
 

Doggggboy

Ultra Member
I have a shop made flycutter that uses a carbide inserted lathe tool as the cutter. I made it using an R8 face mill holder that was not being used. I have used it out to 9 inch diameter and it is very rigid. Small depth of cut and slow spindle speed are best for flycutters. Something like this would be the least expensive tool to try first. If you want to borrow it I can send it in the mail.

A most generous offer, John, but I won't ask you to do that.
I'm not averse to buying a tool that will only see occasional use. Actually, that's kinda all of my hobbies in a nutshell.
Maybe the stupid question of the day , but here goes. Given that the anvil surface is probably not that large, I mean it only weighs 100 lbs, I can't see it having a very big surface area. Other than taking a lot of passes, is there an issue with just using a 1/2 inch end mill?
 

Tom Kitta

Ultra Member
Problem with 1/2 in EM is that the anvil may be a bit too hard even for standard carbide. It all sort of depends on an anvil - what is it. How about you do a little test - see whatever you can file some of the top with a file. People also play around with steel balls and see the bounce. If you can file it even a bit - you can use 1/2 EM and lots of passes. Then you can do a little grinder pass with fine grade of sand paper.

Note that you should not remove too much - the hardened layer is not "forever".

If ball bounces a lot and you cannot file it is probably 50 HRC plus. Can be as high as 60 work hardened - remember it could have started as 55 but could gotten to 60 after a lot of hammer blows. For up to 60 HRC you need a bit stronger carbide.

People do cut hard stuff all the time - it is just hard on the cutter and machine. Hence why grinding is preferred.

When I dealt with old anvil I surface hardened I did not mill it - I used my hand grinder to make it flat. Hand grinder seems to be the way to go. Note there is a youtube video of someone "milling" a true anvil & how much pain it was. https://www.youtube.com/results?search_query=milling+anvil
It all depends how hard things are - someone did one on a shaper with standard HSS - so it all depends on what exactly you have.
 

John Conroy

member
Premium Member
@John Conroy, enjoyed reading your post. When you speak to "Small depth of cut and slow spindle speed are best for flycutters." Can you be more specific on speeds and depth of cut.

How serious is the hit and miss banging at the edges?

I assume the same process would also apply to facing a rectangular item on one's lathe held by a 4 jaw?

As you can see in the picture I used it to refinish the top surface of my cheap import milling vise, which had a .010" height variation end to end. After using the flycutter to do the machine work it was flat to within .0005".
It was set up to cut a 6.5" circle so I ran it slow at 300 rpm and depth of cut was only .003" on each pass. It took 4 passes to get all the low spots. The interrupted cut does cause alot of noise and is probably not very good for the machine so it is best used for softer material. The cast iron on that vise was soft as cheese. I refinished the top of my own little anvil today and found the flycutter unsuitable for the hard surface. I'll post about that later.

In this picture you can see how I marked the low end of the vise at 0 and the high corner was .010' higher.



You can see the finished surface in this picture.



By the way the flat top surface of that vise did not last. A year later it was (and still is) .003" high in the same corner. I complained about it so much that my wife got me a Kurt vise for Christmas that year just to shut me up.
 

John Conroy

member
Premium Member
My little railway track anvil was badly mangled from 50+ years of abuse so I decided to try and refinish it with my fly cutter as I had suggested earlier. It turns out that the fly cutter was not suitable. Too much flex in the cutter maybe. I have a 63mm 4 insert face mill that uses APMT inserts so I gave that a try. I ran it at 600 rpm with .005" depth of cut and a very slow feed rate. I did 4 passes. The surface of the anvil is so work hardened that it was very difficult cutting with lots of sparks but after 3 passes I wound up with a very nice surface finish. I saw the same kind of sparking chips on the Fireball tool video so I assume that is due the hardness of the material. I think this kind of work would be better done on a massive heavy mill like the one in the video but it can be done on a regular size mill if you are patient with feeds and speeds. I should have used my mist coolant system but it's not mounted to this mill yet. I took a video that I'll post to YouTube later so you can see the fireworks and hear how noisy it was.





These are the tools and inserts I used. I'll post links to Ali Express for the R8 holder, the face mill and the inserts. Just examples you might be able to get better deals elsewhere.









https://www.aliexpress.com/item/329...d7f6268b-5&pdp_ext_f={"sku_id":"66743495773"}

https://www.aliexpress.com/item/326...ff34218a-4&pdp_ext_f={"sku_id":"59460379130"}

https://fr.aliexpress.com/item/1005...64-0&pdp_ext_f={"sku_id":"12000018895783653"}
 
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John Conroy

member
Premium Member
In case some of you haven't seen Jason's video. He took a .090" first pass, you can do that with an 18000LB 50 HP mill I guess.


Here's the video I shot.

 
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