3/4” blank slightly to fat for ER 32 3/4” collet

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HugeElvis

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Cartersville GA USA
I have an ER32 collet set from Amazon.


When I buy or pour a 3/4 inch blank, I have to grind down one end to a bit smaller diameter to get it into the largest collet, 3/4. What size collet do I need to fit a 3/4 inch blank and still be able to tighten it onto the blank. Imperial or metric sizing doesn't matter if it will fit into my collet holder.
Thanks,
 
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Typically, when you buy blanks, they are slightly under 3/4 inch if you are buying "kitless" blanks. If you are pouring your own blanks and using PVC, try to get Schedule 80 pipe rather than Schedule 40, which is the more common type found in stores. Schedule 80 has a thicker wall, which makes the blanks slightly under 3/4", and the blanks will fit into your collet. This will also save you a good amount of resin because, if I remember correctly, schedule 80 only takes about 70g of resin to make an 8.5" blank.

I also understand that you can find a 21mm collet that will handle the slightly oversized stock.
 
HugeElvis said:
I have an ER32 collet set from Amazon.


When I buy or pour a 3/4 inch blank, I have to grind down one end to a bit smaller diameter to get it into the largest collet, 3/4. What size collet do I need to fit a 3/4 inch blank and still be able to tighten it onto the blank. Imperial or metric sizing doesn't matter if it will fit into my collet holder.
Thanks,
Click to expand...
If you don't want to change your molds, you can measure the diameter of your blanks in mm and buy an ER32 collet to match. For example, these are just *slightly* bigger than 3/4"... https://www.amazon.com/BORDSTRACT-Precision-Engraving-Machine-Workholding/dp/B0D4R1XQ55/
 
My ER32 set has a 25/32 collet for slightly oversize riund blanks.. To get square to round, I 'jam' the square end into the er holder, set tailstock live center to center & make things round to 3/4, flip into a 3/4 er32 collet & finish rounding the other end
 
I have two oversized er32 collets. I got one from Maritool (7/8) and the other one from Little Machine Shop (13/16). Neither place carried both of the sizes I wanted so I had to buy one from each of them. Try a Google search for oversized er32 collets and both of those companies should come up somewhere in the search results.

Dave

PS I had the same problem before I switched from Schedule 40 to Schedule 80 PVC for my molds.
 
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A word that of advice, if you have the Beall collet chuck be careful using a 13/16 with it. I had a bad experience with my brand new collet chuck…let's just say it didn't end well and because it was brand new and there is a warranty, Lee Valkey replaced it.
 
Thanks to all for the helpful advice. I ordered a 21mm collet and will look for the Schedulule 80 PVC. I quit using PVC after having release issues with Aluminite. I use release agent and had to cut the PVC off the blank. I'm using Pen Kit Mall silicone vertical molds and they are also a bit fat for my 3/4 collet.
 
Those oversized collets are VERY thin at the ends of the slots. Don't drop them as they may well shatter. Keep the collet and chuck spotlessly clean.

ER chucks and collets have a snap ring in the Nut and matching groove in the collet. It is called "Self-ejecting". On a good quality collet and nut the rings will keep the Collet and Nut engaged; cheap ones will not.

PS. There is a specific "load order" for ER 32.
  1. Snap the collet into the Chuck Nut.
  2. Screw the Nut and Collet onto the chuck, loosely.
  3. Insert work piece or tool, tighten.
Removal order:
  1. Unscrew the Nut until it tightens. Unscrew more until it "snaps" and gets loose again.
  2. Remove work piece or tool.
  3. Remove Nut and Collet from Chuck.
  4. Unsnap the collet from the Nut.
 
I guess that I work backwards. When I get an oversized or irregular shaped blank I mount it between centers and round or nearly round it. Then I measure and put it in the proper collet. Metric collet sets can handle anything from aout 1/8" to 3/4", then I drill and prceed. Just my $.02
 
rixstix said:
My Beall nut fits the definition of "cheap ones" since the collet has always just fallen out of the nut if not held just right.
Click to expand...
I use these for my Sliding Collet Holder...

www.ebay.com

NEW PRECISION BALANCE ER32 COLLET NUT TOOL HOLDER COLLET NUT USA | eBay

Collet Nut holds all ER32 collets. BALANCE COLLET NUT G2.5 20000RPPM. Our ER32-UM Wrench works on this collet nut. Internal cam removes collet when unscrewed. This nut is a bearing nut and has internal ball bearings.
www.ebay.com

Good quality at a good price.
 
Rick; That Chuck nut looks inviting.

General Info:
ER collets & chucks come in several "families" from ER-8 to ER-50 (higher numbers are larger). The families are NOT interchangeable from family to family. ie. an ER-16 collet will not fit in an ER-32 chuck.
BUT within a family all the nuts, chucks and collets ARE interchangeable; so ANY ER-32 nut, collet, or chuck ARE interchangeable.
There is a virtual alphabet soup of collet styles. They are not interchangeable.
 
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