ER40 vs. 5C collets accuracy in a lathe?

[Bob Korves]

(snip)I have once again confirmed what I knew already – “A little here and a little there and soon you have spent some real money.”(snip)

I have a set of Interstate 5C collets (Chinese) by sixteenths, a 5MT to 5C adapter to fit the lathe spindle, an in progress shop made hand wheel collet closer for my lathe, a set of 5C collet blocks, and a spindex. Oh, and a 5C end mill grinding fixture for the surface grinder. I have about $250 into all that and it gives me quite a bit of capability.

 

[mksj]

I have seen some individuals make slide out collet trays out of steel or wood, very nice. Since I have no more draw space and I wanted the 5C collets readily available, I mounted three 5C racks on the end of my cabinet. I like being able to quickly stick stock in a collet to see if it fits for those odd size items. On the ER-32 collets and r-8 that I frequently use in my mill, they are in wood blocks in my machine tool cabinet draws next to the mill. My ER-40 collets which I use less frequently, I rebuilt the case that they came in to accommodate more collets and also so it wouldn't fall apart. Most of the cases the ER collets sets are pretty worthless. I went with a 1/32" increment ER-40 set along with a few high precision metric for my indicators. Note that many 1/32" ER sets are missing certain less frequently used sizes and I had to back fill the missing sizes, go figure.

 

[woodchucker]

Neither are more accurate over the other, as mentioned, too many variables but it comes down to the quality of the collect chuck, closure, etc as well as the quality of the collets, thay are not all equal. Each has their advantages & disadvantages which you have to decide what suits you better.

I have ER40 for use in the lathe but only cause I use ER40 in the mill & don't have a set of 5C collets. If I didn't use ER40 in the mill, I might have ended up using 5C for the lathe or if I had to do it over I would use TG150 collets for the lathe.

ER collets were not designed for workholding, they were designed for toolholding, the same for TG collets. But of course that doesn't matter or stop anyone. The use of ER for workholding seems to be popularized by hobbyist. You don't often see ER collets being used for workholding in machine shops if at all.

Possibly because a shop is already loaded to the gills with 5C's. So no need to invest in new. Just sayin

 

[Alan H.]

Mark, Where did you acquire the 5C racks?

 

[Tozguy]

Alan, unfortunately I have nothing to say about the original question on which is more accurate. However permit me to disagree with some of your conclusions in the above post. My choice was an ER32 set for work holding. The reason being that my larger chucks do not hold work smaller than 1/2'' very well. Anything larger I can handle accurately with a 4 jaw independent chuck. ER chucks with through holding possibilities are available (ex. Beall). Many of us have made our own. So there is no problem using ER collets for work holding.

My initiation to collets was the purchase of an R8 ER32 set. Then I made up a D1-4 ER chuck and borrow the nut, collets and wrench from the R8 kit to use it. I also have made up an MT5 to R8 sleeve to be able to use the R8 chuck in the lathe spindle. This is gives me a fair amount of versatility with respect to undefined future needs. Buying tools before they are needed seems to me like a good way to end up with tools I don't need so I was conservative (I think).

I prefer to use an MT3 Weldon style holder with a drawbar for holding tools because it is easier to use than an ER chuck and more accurate in my opinion.

Hopefully your requirements are clearer than mine and your choice of 5C versus ER can be based on more specific needs.

 

[mksj]

The 5C racks are pretty standard, mine where from Enco, but most tooling companies and eBay list the same or similar collet racks.
https://www.amazon.com/30-PIECE-5C-COLLET-RACK/dp/B00DVTSAHM

On ER collets they are designed to hold material along the full length of the collet and the collet collapses/tightens from both ends. Short stock held in an ER collet will asymmetrically tighten the collet if the piece is not held by the full collet. The shorter the piece, the more this becomes a problem. I am often gripping very short pieces (0.1-0.25") in 5C collets, I do not think this would be possible using an ER collet. That being said, when threading I have had stock turn in 5C collets, and ER collet with longer stock would most likely hold it more secure when using it as a lathe chuck.

 

[Bob Korves]

The 5C racks are pretty standard, mine where from Enco, but most tooling companies and eBay list the same or similar collet racks.
https://www.amazon.com/30-PIECE-5C-COLLET-RACK/dp/B00DVTSAHM

On ER collets they are designed to hold material along the full length of the collet and the collet collapses/tightens from both ends. Short stock held in an ER collet will asymmetrically tighten the collet if the piece is not held by the full collet. The shorter the piece, the more this becomes a problem. I am often gripping very short pieces (0.1-0.25") in 5C collets, I do not think this would be possible using an ER collet. That being said, when threading I have had stock turn in 5C collets, and ER collet with longer stock would most likely hold it more secure when using it as a lathe chuck.

Mark, I have that same Enco rack and am using it horizontally. It appeared to me when I first started using it that it would not work well vertically because the drawbar ends of the collets would drop onto the rows below due to gravity, causing problems with putting them back into the rack. Yet you seem to have done it. I can see that your empty bottom rack has no spacers between the rows. Have your racks been modified, and how do they work in the vertical orientation?

 

[Silverbullet]

You can find good and bad in everything. I'm old school , graduated in 1974 from vocational . I've used many different collets and brands over the years . I have ran lathes with all styles of collets even three piece in turret lathes. Most if not all will do excellent work. That said I have 5 c on my logan lathe , but I will be having er32 collet set up on my mill. My reason is I'm in a wheelchair and the changing of tooling won't be a hardship for me to reach up to change r8 collets in it. Other wise I'd stick with the r8 s. I see nothing wrong with any of the collet choices other then size limits. Now with acquiring an atlas mill ill be using 2 morse collets to a er32 change over . Only to get the size change for tooling. I do remember one kind we had trouble with it was the rubber mounted Jacob's collet chuck system , we had them let material twist and even push sideways. I never had it but I've seen when it happened. But if I owned one I'd use it.

 

[Alan H.]

Alan, unfortunately I have nothing to say about the original question on which is more accurate. However permit me to disagree with some of your conclusions in the above post. My choice was an ER32 set for work holding. The reason being that my larger chucks do not hold work smaller than 1/2'' very well. Anything larger I can handle accurately with a 4 jaw independent chuck. ER chucks with through holding possibilities are available (ex. Beall). Many of us have made our own. So there is no problem using ER collets for work holding.

My initiation to collets was the purchase of an R8 ER32 set. Then I made up a D1-4 ER chuck and borrow the nut, collets and wrench from the R8 kit to use it. I also have made up an MT5 to R8 sleeve to be able to use the R8 chuck in the lathe spindle. This is gives me a fair amount of versatility with respect to undefined future needs. Buying tools before they are needed seems to me like a good way to end up with tools I don't need so I was conservative (I think).

I prefer to use an MT3 Weldon style holder with a drawbar for holding tools because it is easier to use than an ER chuck and more accurate in my opinion.

Hopefully your requirements are clearer than mine and your choice of 5C versus ER can be based on more specific needs.

Toz, no problem - I pointed out that folks use the ERs for workholding in my #3. Didn't mean to say you couldn't and I am glad you find it good for you.

Ref. my learning #5 on chucks (context of this thread was for a D1-4 camlock mount) - my research here and elsewhere showed few off the shelf D1-4 options for an ER chuck. The one that is readily available has given folks some runout problems. Btw, you mentioned Beall and I do have a Beall ER 32 collet chuck and collets for my Powermatic wood lathe but it is a screw mount and was intended for woodworking.

Meanwhile, I will likely buy some of both types and use them as indicated. I have a mill that I am also outfitting as needed.

 

[Bob Korves]

Toz, no problem - I pointed out that folks use the ERs for workholding in my #3. Didn't mean to say you couldn't and I am glad you find it good for you.

Ref. my learning #5 on chucks (context of this thread was for a D1-4 camlock mount) - my research here and elsewhere showed few off the shelf D1-4 options for an ER chuck. The one that is readily available has given folks some runout problems. Btw, you mentioned Beall and I do have a Beall ER 32 collet chuck and collets for my Powermatic wood lathe but it is a screw mount and was intended for woodworking.

Meanwhile, I will likely buy some of both types and use them as indicated. I have a mill that I am also outfitting as needed.

I think some people machine their own setup with a separate back plate, and leave the register a bit sloppy on purpose so they can use it as a "bump true" adjustable chuck for initial setup and for dialing it in with fussy work. That makes good sense to me...