R8 Shell Mill Holder

[sbosecker]

I may be getting the terminology wrong so...
I'm looking for a vendor that sells a R8 Shell Mill Holder with a 16mm Bore (Pilot?)
I have found this vendor in the UK but I'd prefer to find a vendor in the USA if possible as I'm not sure how customs and such would work with an item arriving from overseas.

Scott

 

[landlord30]

This what you want?

https://www.ebay.com/itm/New-16mm-R8-Shank-Milling-Arbor-Gear-Mill-Cutter-Holder-/172052359753

 

[zkling]

Call Lyndex. Metric shell mills are far and few between usually. What do you have?

 

[sbosecker]

This what you want?

https://www.ebay.com/itm/New-16mm-R8-Shank-Milling-Arbor-Gear-Mill-Cutter-Holder-/172052359753

landlord30,

No...

This is what I want:

LINK

Best regards,

Scott

 

[sbosecker]

Call Lyndex. Metric shell mills are far and few between usually. What do you have?

zkling,




Dormer D40040.0 40mm Shell Mill



I had looked at the online Lyndex R8 Shell Mill Holders and all that were listed were Imperial bore sizes from 1/2" to 1-1/2".


Best regards,

Scott

 

[zkling]

I wouldn't waste time or money on trying to put that on a R8 machine. If you want something to surface with, get a good low hp insert face mill from Mari tool or the like. Even better an integrated r8 shank cutter.

 

[sbosecker]

I wouldn't waste time or money on trying to put that on a R8 machine. If you want something to surface with, get a good low hp insert face mill from Mari tool or the like. Even better an integrated r8 shank cutter.

zkling,

Would you mind explaining what is wrong with that shell mill on a R8 machine?

Could you be a little more specific with the "low hp insert face mill from Mari tool or the like"?

Best regards,

Scott

 

[MattT]

Would you mind explaining what is wrong with that shell mill on a R8 machine?

There's nothing wrong with the shell mill itself. Just not worth tooling up for it if you only have one of them.

 

[DocsMachine]

Would you mind explaining what is wrong with that shell mill on a R8 machine?

-It has to do with both horsepower and rigidity. A shell mill used for facing isn't bad, if the depth-of-cut isn't too much, but that mill used for side cutting would take a big chip, even at minimal DOC.

Typically the R8 machine is both limited in HP to take much of a cut with such a tool, and the rigidity to give you a good surface finish when doing so.

Cutting aluminum is better, of course, but that big a mill cutting steel is technically over the limit of a Bridgeport type machine.

If you want to do wide facing, you'd be better off with a proper facing cutter, like these- look down at the "integral shank" ones. The honed-sharp inserts produce an amazing finish in aluminum- I haven't tried the steel or cast iron inserts (I work mostly in aluminum) but I'd be surprised if they didn't work as well.

Yeah, it's not particularly cheap, but it's a top-notch setup.

Doc.

 

[matt_i]

I'm also in the camp of "don't put that on a bridgeport". There is no outcome where you can use the full side of it without chatter. It belongs on a horizontal mill IMO, and I have used them successfully on Cat40 tooling in a horizontal.

What is better is a 4-cutter inserted carbide face-mill. I wouldn't go more than 2" diameter. I have bought them from Shars, with the R = round inserts, add an R8 shank. Work great on mild steel, aluminum, delrin. Obviously keep depth of cuts down especially on steel (start small, say .010" depth) , and keep the head in tram. If you chip an insert, just rotate it slightly, only a small amount of the insert is actually cutting.

 

[lilscorpion]

I'm also in the camp of "don't put that on a bridgeport". There is no outcome where you can use the full side of it without chatter. It belongs on a horizontal mill IMO, and I have used them successfully on Cat40 tooling in a horizontal.

In general I'd agree but with caveats. Scott didn't really share what he's intending to do with a shell mill, he was just asking where to get the arbors. I've used them for years on my J-Head style R8 machine without issue but for very specific and intentional reasons.

e.g. - I've used rougher shell mills to notch heavy wall and large diameter DOM tubing for years in a production environment. I got into them as a much faster and more accurate way over other methods I tried using other types of tooling on a CNC. It just turns out that overall operation time, tool life, and minimized deflection made them the clear winner.

Scott - my .02 on arbors - I didn't buy anything fancy. One of mine was purchased off of ebay (most certainly import) years ago and the other two I got at an auction. I use them interchangeably (meaning I don't favor one over the other) and I've never tested any of them for runout nor have I had a reason to do so. As far as arbors go, they just work for my intended use-cases. As others have mentioned though, make sure your use-case for a shell mill matches the capabilities of your machine.

I'll give the same advice for just about all of my R8 tooling. You can spend huge dollars on holders or you can find cheaper holders that have adequate runout for the quality work you intend to do. Nothing I build goes into space so 99 times out of a 100 my parts are higher accuracy than they need to be given how they're used and I think I make nice parts. I have maybe 3 dozen R8/ER-style holders which I spent no more than $400 for all ordering them in bulk direct from China (via ebay). I've used them for years and they're fantastic. Though I support USA manufacturing, I just can't justify having only 3 holders for that same $400 or spending $4000 to buy the dozens I need (I have a CNC so dedicated holders for tooling is really what makes a CNC valuable).

 

[sbosecker]

There's nothing wrong with the shell mill itself. Just not worth tooling up for it if you only have one of them.

-It has to do with both horsepower and rigidity. A shell mill used for facing isn't bad, if the depth-of-cut isn't too much, but that mill used for side cutting would take a big chip, even at minimal DOC.

Typically the R8 machine is both limited in HP to take much of a cut with such a tool, and the rigidity to give you a good surface finish when doing so.

Cutting aluminum is better, of course, but that big a mill cutting steel is technically over the limit of a Bridgeport type machine.

If you want to do wide facing, you'd be better off with a proper facing cutter, like these- look down at the "integral shank" ones. The honed-sharp inserts produce an amazing finish in aluminum- I haven't tried the steel or cast iron inserts (I work mostly in aluminum) but I'd be surprised if they didn't work as well.

Yeah, it's not particularly cheap, but it's a top-notch setup.

Doc.

I'm also in the camp of "don't put that on a bridgeport". There is no outcome where you can use the full side of it without chatter. It belongs on a horizontal mill IMO, and I have used them successfully on Cat40 tooling in a horizontal.

What is better is a 4-cutter inserted carbide face-mill. I wouldn't go more than 2" diameter. I have bought them from Shars, with the R = round inserts, add an R8 shank. Work great on mild steel, aluminum, delrin. Obviously keep depth of cuts down especially on steel (start small, say .010" depth) , and keep the head in tram. If you chip an insert, just rotate it slightly, only a small amount of the insert is actually cutting.

MattT, Doc & matt_i,

Thank you all for your thoughtful posts. I will look into alternative's to the shell mill as well.

Best regards,

Scott

 

[sbosecker]

In general I'd agree but with caveats. Scott didn't really share what he's intending to do with a shell mill, he was just asking where to get the arbors. I've used them for years on my J-Head style R8 machine without issue but for very specific and intentional reasons.

e.g. - I've used rougher shell mills to notch heavy wall and large diameter DOM tubing for years in a production environment. I got into them as a much faster and more accurate way over other methods I tried using other types of tooling on a CNC. It just turns out that overall operation time, tool life, and minimized deflection made them the clear winner.

Scott - my .02 on arbors - I didn't buy anything fancy. One of mine was purchased off of ebay (most certainly import) years ago and the other two I got at an auction. I use them interchangeably (meaning I don't favor one over the other) and I've never tested any of them for runout nor have I had a reason to do so. As far as arbors go, they just work for my intended use-cases. As others have mentioned though, make sure your use-case for a shell mill matches the capabilities of your machine.

I'll give the same advice for just about all of my R8 tooling. You can spend huge dollars on holders or you can find cheaper holders that have adequate runout for the quality work you intend to do. Nothing I build goes into space so 99 times out of a 100 my parts are higher accuracy than they need to be given how they're used and I think I make nice parts. I have maybe 3 dozen R8/ER-style holders which I spent no more than $400 for all ordering them in bulk direct from China (via ebay). I've used them for years and they're fantastic. Though I support USA manufacturing, I just can't justify having only 3 holders for that same $400 or spending $4000 to buy the dozens I need (I have a CNC so dedicated holders for tooling is really what makes a CNC valuable).

lilscorpion,

Thank you.

The situation with this shell mill... I had seen some YouTube videos that featured a shell mill doing some work and went on-line to see what they cost.

If I remember what happened correctly, I was looking at Zoro.com [because I had a 25% coupon] and they had some Dormer shell mills listed. I think I was looking at the Dormer D40050.0 50mm shell mill on Zoro and it was listed at about $272 and then I saw the Dormer D40040.0 (40mm) was listed at about $147.

I decided to compare Zoro's price to Amazon just to see if they were roughly comparable in price. The 50mm Dormer was about $239 on Amazon (out of stock) and then I looked at the 40mm Dormer...

$23.78 - one left in stock...

WTF?

I did some internet due diligence and decided that. at 16% of the average price found, this was worth rolling the dice. I purchased the 40mm Dormer.

When I clicked on the Amazon listing after I hit the buy button, the Shell Mill now showed out of stock with a price of about $172.

Weird.

I am aware of the "Concorde Fallacy" (sunk costs fallacy). This is an economic behavior that justifies further expenditures due to previous expenditures. I suppose to some degree that IS what I am doing if I obtain a 16mm Shell Mill Arbor for this 40mm Dorian.

However, if I can obtain a R8-16mm Shell Mill Holder for relatively small money, I will probably do so just to experiment with what this tooling can do.

Best regards,

Scott

 

[APEowner]

Do you have a lathe? If so you can make a holder. Every couple of years I make up a batch of R8 blanks. When I need to mount something weird in the mill I install the blank in the mill and turn the end for the application using tooling held in the mill vice.

 

[racingtadpole]

With regard to how customs works if you bought a holder from overseas, it should just turn up on your door. If there is duty payable then you will be notified with instructions on how to pay (this is a rare occurrence in my experience of shipping to the US).

 

[manwithtools]

Do you have a lathe? If so you can make a holder. Every couple of years I make up a batch of R8 blanks. When I need to mount something weird in the mill I install the blank in the mill and turn the end for the application using tooling held in the mill vice.

How is this even worth your time given the price of R8 collets? Just buy the cheap collets and chuck up a piece of round stock (drill rod) in them to make the custom tooling. Unless you have a lot of free material and have making R8 profiles down to science, I can't understand this.

Am I missing something?

 

[APEowner]

How is this even worth your time given the price of R8 collets? Just buy the cheap collets and chuck up a piece of round stock (drill rod) in them to make the custom tooling. Unless you have a lot of free material and have making R8 profiles down to science, I can't understand this.

Am I missing something?

I can make 10 of them in about 2 hours so at my shop rate of $100/hour they cost me $20/each. Material is just drops of whatever steel I have laying around that's at least 6" long and 1 1/4" in diameter. The taper is the only setup that takes any time and is the only reason I run more than one part at a time. Once I'm setup for that I prefer to run a handfull of parts.

Collets are great but the tooling can pull out under heavy cuts so I don't use them for anything harder than aluminum and if the part is expensive I don't even use them for that.

 

[MattT]

I decided to compare Zoro's price to Amazon just to see if they were roughly comparable in price. The 50mm Dormer was about $239 on Amazon (out of stock) and then I looked at the 40mm Dormer...

$23.78 - one left in stock...

WTF?

I did some internet due diligence and decided that. at 16% of the average price found, this was worth rolling the dice. I purchased the 40mm Dormer.

When I clicked on the Amazon listing after I hit the buy button, the Shell Mill now showed out of stock with a price of about $172.

Weird.

They do that quite a lot on obscure expensive stuff. It doesn't move so they keep discounting it until somebody bites. I've bought a lot from them that way and they have to have lost heavily on all of it. Doubt they even covered the 2nd day air shipping on some.

I am aware of the "Concorde Fallacy" (sunk costs fallacy). This is an economic behavior that justifies further expenditures due to previous expenditures. I suppose to some degree that IS what I am doing if I obtain a 16mm Shell Mill Arbor for this 40mm Dorian.

However, if I can obtain a R8-16mm Shell Mill Holder for relatively small money, I will probably do so just to experiment with what this tooling can do.

That'll work if you can get an arbor cheap enough that it doesn't become its own "concorde fallacy" when the shell mill gets dull. You don't want to get in a situation where you're dumping money into expensive metric replacements because you already have the arbor.

 

[DocsMachine]

Oy.

First off, collets aren't consumables. One set should last even a busy machinist many, many years. The first set of cheap imports I had I bought back in probably '94 or '95, and I still use them today. And yes, they still hold well and are still very concentric.

Last year I splurged and got myself a set of Hardinge collets, which are basically the best you can buy (and I'm pretty sure the only American-made ones.) Not cheap, but I needed a second set since I got the second mill up and running, and considering how long the cheapies lasted, I'll be handing these Hardinges down to my still only theoretical grandchildren.

Being able to make 10 an hour would virtually require either a big, heavy lathe capable of cutting a heavy chip, or a fast CNC- and not everyone has either of those.

Really, the only reason to bother making an R8 anything these days is if you need something particularly oddball. Shell mill holders can be had by the fistful, collets are dirt-cheap if you don't mind imports, ER collet holders can be had in anything from ER11 up to ER40, you can get slitting saw arbors, horizontal arbors, Morse taper adapters, Jacobs taper adapters, integral-shank drill chucks or fly cutters, you name it.

I could see the use of a sort of R8 "emergency" collet or arbor, kind of like the 5C emergency collets, but really, I've been a machinist specializing in weird parts and strange setups for over 20 years, and have never really needed one.

Doc.

 

[APEowner]

Oy.

First off, collets aren't consumables. One set should last even a busy machinist many, many years. The first set of cheap imports I had I bought back in probably '94 or '95, and I still use them today. And yes, they still hold well and are still very concentric.

Last year I splurged and got myself a set of Hardinge collets, which are basically the best you can buy (and I'm pretty sure the only American-made ones.) Not cheap, but I needed a second set since I got the second mill up and running, and considering how long the cheapies lasted, I'll be handing these Hardinges down to my still only theoretical grandchildren.

Being able to make 10 an hour would virtually require either a big, heavy lathe capable of cutting a heavy chip, or a fast CNC- and not everyone has either of those.

Really, the only reason to bother making an R8 anything these days is if you need something particularly oddball. Shell mill holders can be had by the fistful, collets are dirt-cheap if you don't mind imports, ER collet holders can be had in anything from ER11 up to ER40, you can get slitting saw arbors, horizontal arbors, Morse taper adapters, Jacobs taper adapters, integral-shank drill chucks or fly cutters, you name it.

I could see the use of a sort of R8 "emergency" collet or arbor, kind of like the 5C emergency collets, but really, I've been a machinist specializing in weird parts and strange setups for over 20 years, and have never really needed one.

Doc.

Doc,

Maybe I'm misreading this but this feels I annoyed you for some reason. I'm not sure why that would be but if that's the case I apologize. Let me see if I can clarify some things.

I use collets a lot and I don't think of them as consumables. Mine are a combination of used expensive ones and cheap new ones and I use them all without thinking about which is which. I don't like to use them when cutting pockets, or in harder materials or with tooling like fly cutters, shell mills or face cutters because I've seen them slip when pushing (or technically exceeding) the limits of the machine.

I said that I can make 10 R8 arbors in about 2 hours (not 1) and that I make a bunch every couple of years. I went back and checked and the last time I made a run was slightly under 5 years ago, I still have two blanks in my tooling drawer and I only made 9 in 2 hours (I'm guessing that I only had stock on hand for 9) so my shop time wasn't as efficient as I remembered and I don't use them as often as I thought.

None of that negates the fact that if I was in the OPs position I could grab an arbor blank out of a drawer and be making chips with that shell mill pretty quickly and that he could make an arbor if he can't find one. That's all I was trying to communicate. If that's helpful to him or someone else that's great. If it's not that's OK too.

 

[sbosecker]

Just completed the purchase of a R8-16mm Shell Mill Holder; almost certainly made in China. The item was on eBay and located in the UK. It had gone unsold when the first auction for it had ended (no bids) prior to my searching for this bit of tooling.

A few days ago I had sent an eBay message to the owner of the auction indicating my willingness to purchase the Holder for his original opening bid price with a Buy-It-Now.

Crickets ...until this morning.

The item showed up on eBay again with a buy-it-now as I had requested and I received a message from the seller. I hit the Buy button.

Link to the eBay listing.

The shipping to the USA from the UK is almost 2/3rds of the purchase price. Ha!
Still... a bit over $30 for something I can't find within a 2500 mile radius of Peachtree City GA doesn't seem too bad.

I'm sure this will take a few days but I am expecting to receive a R8-16mm Shell Mill Holder in the near future.

Scott

 

[MattT]

If you feel like taking a chance on some more chinesium tooling this should get some more use out of that arbor once the shell mill is used up.

https://www.ebay.com/itm/90-40mm-4F...e-face-milling-cutter-face-shell/162784986283

 

[alexb2000]

The OP didn't saw what machine this is going on, but probably a fair guess it's a Bridgeport. IMO tooling up a Bridgeport correctly is one of the keys to getting good results with the machine and they just don't like a lot of what is available and often "cheap". Bridgeport's just don't have the rigidity and power to just plow through anything like say a K&T would. When I look at my R8 rack the tools I use for 99% of my work number less than 10, but I bought a whole pile of tooling to figure that out.

Maybe 2-3 different endmills in ETM endmill holders (I'll change the endmill themselves based on material)
Albrecht 1/2" chuck
Albrecht small drill chuck
Jacobs super chuck 1/2" (need keyed for tapping or left hand ops)
2.5" Carbide Insert Facemill-Kennametal
3" Criterion boring bar
Slitting saw arbor- I can't remember the brand but it's quality

I have a collet set, all kinds of other specialty stuff, but the above list does most all of my work (I don't like collets for end mills because they spin under load very easily).

If I had it to do over again I would buy a list like the above and forget about all the "good deals" for tooling that are so common (for a reason).

Just my .02

 

[MattT]

Collets are great but the tooling can pull out under heavy cuts so I don't use them for anything harder than aluminum and if the part is expensive I don't even use them for that.

(I don't like collets for end mills because they spin under load very easily).

Are you guys tightening the drawbar with your fingers?

 

[alexb2000]

Are you guys tightening the drawbar with your fingers?

No, I have a Kurt drawbar, so basically the tooling is impacted on. If it wasn't a problem I wonder why endmills have flats milled on them?

 

[DocsMachine]

No, I have a Kurt drawbar, so basically the tooling is impacted on.

-Then you have a problem somewhere. An R8 collet has quite a bit of holding power- no, they're not as powerful as a 40 taper, but properly applied, they work very well for the average small shop or home shop use.

If you're using a power drawbar, but still finding an endmill moves too easily in the collet, you have a problem somewhere. Not enough air pressure to the drawbar wrench, perhaps, or an overrun clutch is maladjusted.

Another possibility is your spindle taper is damaged or worn, and no longer provides the proper clamping force on the collet. The collet itself may have been damaged from a prior spin or crash- or excessive use when left too loose- and will no longer grab well.

Or you're severely overloading the collet, by trying to bury an oversized endmill into alloy steel, or using a too-large facemill or shell mill while taking a too-deep cut, or forcing a too-fast feed rate, etc.

Yeah, you treat an R* machine like you would a 10HP NMTB40 machine, and that collet isn't gonna hold up. But I've been running R8 machines since about '94, and the only time I've spun something in a collet is when I stupidly tried to use a 1/2" collet to hold a 1/2" drill.

And it's not just me- there's literally about 20 million R8 machines out there, and very, very few of them are having the kinds of problems you are.

Doc.

 

[sbosecker]

Just completed the purchase of a R8-16mm Shell Mill Holder; almost certainly made in China. The item was on eBay and located in the UK. It had gone unsold when the first auction for it had ended (no bids) prior to my searching for this bit of tooling.

A few days ago I had sent an eBay message to the owner of the auction indicating my willingness to purchase the Holder for his original opening bid price with a Buy-It-Now.

Crickets ...until this morning.

The item showed up on eBay again with a buy-it-now as I had requested and I received a message from the seller. I hit the Buy button.

Link to the eBay listing.

The shipping to the USA from the UK is almost 2/3rds of the purchase price. Ha!
Still... a bit over $30 for something I can't find within a 2500 mile radius of Peachtree City GA doesn't seem too bad.

I'm sure this will take a few days but I am expecting to receive a R8-16mm Shell Mill Holder in the near future.

Scott

Well this "delivery" just got more interesting. I was given a Royal Mail tracking number (RN249921861GB) and had noticed a couple of days ago that the package seemed to have gone to Korea.

Odd ...but who am I to question the Royal Mail's methods.

A few minutes ago I got a message from eBay. My package had been delivered.

I walked out to the mailbox, checked the front porch and in front of the garage doors.

Nothing.

Came back into the house and put the tracking number into the Royal Mail's tracking service and then clicked on the "Continue Tracking" button under "Delivery Partner".

My R8-16mm Shell Holder appears to have been delivered to someplace in Korea.

A query has been sent to the seller.

Scott

 

[sbosecker]

...My R8-16mm Shell Holder appears to have been delivered to someplace in Korea.
A query has been sent to the seller...

The query was sent after business hours (UK time) last Friday. On Monday I received a eBay message from the seller. It seems he/she had put the wrong tracking number on the message I had received regarding this purchase.

An updated tracking number was sent to me and, on Monday, the R8-16mm Shell Mill Holder was in New York.





Today a package arrived in the mail.






The Dormer 40mm Shell Mill mates up nicely with today's arrival.

I've got a bit less than $55 in this - I hope to try it out soon.


Scott

 

[alexb2000]

-Then you have a problem somewhere. An R8 collet has quite a bit of holding power- no, they're not as powerful as a 40 taper, but properly applied, they work very well for the average small shop or home shop use.

If you're using a power drawbar, but still finding an endmill moves too easily in the collet, you have a problem somewhere. Not enough air pressure to the drawbar wrench, perhaps, or an overrun clutch is maladjusted.

Another possibility is your spindle taper is damaged or worn, and no longer provides the proper clamping force on the collet. The collet itself may have been damaged from a prior spin or crash- or excessive use when left too loose- and will no longer grab well.

Or you're severely overloading the collet, by trying to bury an oversized endmill into alloy steel, or using a too-large facemill or shell mill while taking a too-deep cut, or forcing a too-fast feed rate, etc.

Yeah, you treat an R* machine like you would a 10HP NMTB40 machine, and that collet isn't gonna hold up. But I've been running R8 machines since about '94, and the only time I've spun something in a collet is when I stupidly tried to use a 1/2" collet to hold a 1/2" drill.

And it's not just me- there's literally about 20 million R8 machines out there, and very, very few of them are having the kinds of problems you are.

Doc.

Well a couple of ways to go here...

IF you have a new clean dry Hardinge brand collet, holding a 3/4" or less high quality endmill, inserted in a clean Hardinge factory ground spindle, held by a properly lubricated drawbar, with good threads, and torqued appropriately; then the endmill will stall the mill before it spins. You are 100% right.

Running old worn machines, using a lot of less than perfect tooling, push the machine hard and you end up finding the weak link, and in my case it is often the collet to endmill interface especially with large endmills taking heavy cuts in harder steels. With Hardinge collets in the $50 range each, I just find it to be more cost effective, forgiving, reliable, repeatable, and qucker to use an endmill holder.

Or the shorter version...

Do whatever works for you, I am just a **** machinist wasting time on the Internet.

 

[bimmer1980]

Good to see that you received the parts to make your shell mill work. Now I'm curious to see what you will be milling with it....

Interesting comments..... Its been awhile since I have run a bridgeport..... mine is still in storage while I was building the garage....