Thread: NT 30 spindle spanner

Hi Stuart,
Nice job on the spanner.
I only use my spanner to nip up the draw bar, for doing up the collet chuck I used to use aluminium jaws in my bench vise to do them up. I positioned it so the 4 corners collet chuck where the slot is grip on the aluminium.
After buying a NT 30 fixture, I used that from then on but you do need to bolt it down to something solid. I was going to make one, but after getting it for $30 from the US and combining postage with other gear, it just wasn't worth it.

The torque needed for a NT30 nut is around 100 ft/lbs and ER40 is around 130 ft/lbs, so hanging off the standard spanner is only just enough to hold it there.
I always oil my collet chuck inside with a thin smear, and my collets are always oiled, this helps with tightening them up because when they are dry they can bind which prevents torquing them up properly.
Even with the oil, when I use larger end mills like 20mm, I always give the spanner a bump with the dead blow hammer. A longer spanner would be better.

For torquing them up properly, I do have it saved somewhere a program that allows you to use a standard torque wrench with a home made fitting on the end, and it will tell you the amount of torque needed to accomplish what you need,(hope thats understandable, LOL)

Keep up the good work

Dave

I have been tightening my ER collet chucks while mounted in the spindle nose with low gear engaged. Nothing has worked loose so far,TF. I see examples of bench mounted 30 taper chuck holding blocks or mounts on Ebay and whilst their expense is one thing that puts me off, I've always thought that I was tightening the collet nut sufficiently, spindle mounted, not to bother with acquiring one of the mounts.

Am I courting disaster with my current practice?

BT

Using low gear may not be a problem but use of a vertical fixture mounted on a bench or in a vise would be preffered.
They are not hard to make.

Often I have to install a cutter by removing the nut and collet, inserting the cutter in the collet then reassemble it all in the chuck. This due to the lack of vertical clearance I have on the little mill. There is not enough room to remove the chuck with a cutter installed.

A spanner that engages the spindle drive dogs a la Dave, Ray or Stu's sounds like a worthwhile project. A 30 taper vice block would be a simple enough thing to also knock up out of some soft 1214.

BT

Hi Bob,
It's only a matter of time until an end mill pulls out. I remember some jobs where I had only tightened it up in the mill and it had me head scratching why my pockets where getting deeper each pass. After checking the quill lock etc, it ended up being the collet not tight enough and the end mill getting pulled out. It can mess up a good job quick, so tightening them properly is your insurance.

I picked my fixture up for around $30 from these guys below, they are not listed at the moment so you will have to keep a look out as they come and go. I ordered a lot of smaller lighter gear that was a waist of flat rate postage, so this brought up the weight.
Comparing the cost to H&F, they where around $300 plus for the same thing. They are also the ones that have lathe dogs cheap (around $6 each) so you can get a full set up to 3 inch for what H&F wants for one 1 1/2 inch one.
15 Pc ER40 Spring Collet Set Collets NMTB 40 Chuck items in EZ Accessory store on eBay!
NT30 fixture.jpg
You could make one up easy enough, but if your like me you never get around to it, thats why I just ended up buying one.
BT30/ CAT30 Tool Tightening Holder/ Fixture, CNC Manufacturing Work Bench | eBay

These are getting sold on ebay at the moment and are only $59 posted, if you don't have the time they would be the way to go.

These below are what one company sell to go on there special torque wrenches, these could also be made up to go on a standard torque wrench as I mentioned earlier.
TWA_ER32_slot_web.jpgTWA_ER_slotted_web.jpg
Dave

Originally Posted by Anorak Bob

Often I have to install a cutter by removing the nut and collet, inserting the cutter in the collet then reassemble it all in the chuck. This due to the lack of vertical clearance I have on the little mill. There is not enough room to remove the chuck with a cutter installed.

A spanner that engages the spindle drive dogs a la Dave, Ray or Stu's sounds like a worthwhile project. A 30 taper vice block would be a simple enough thing to also knock up out of some soft 1214.

BT

Is this because you maybe using tooling not suited to the size of your machine?

Originally Posted by pipeclay

Is this because you maybe using tooling not suited to the size of your machine?

Peter, that could be the case but I think it has more to do with the limited working envelope. The mill has a 2 horsepower motor and the standard chuck supplied back in 1962 was an E32. On the weekend I had to drill an 8mm hole in a round bar held in the dividing head's 3 jaw chuck. To install the standard length 8mm twist drill in an ER25 chuck required the removal of the nut and collet simply because of a lack of space.

Here's a catalogue picture of young Willem at work with a larger cutter than I have. He seems happy enough.

I added a link I forgot at the bottom of my last post. Something like that would be easy enough to make up out of aluminium or steel and the mounting plate could be just welded or clamped on. Instead of machining the blocks in place, they could be made separately and bolted on as well.
BT30/ CAT30 Tool Tightening Holder/ Fixture, CNC Manufacturing Work Bench | eBay

Dave

My MT collet chuck has spanner flats on the body and I made a simple spanner to suit. Do the NT ones not have the flats?

Originally Posted by Bryan

My MT collet chuck has spanner flats on the body and I made a simple spanner to suit. Do the NT ones not have the flats?

No flats at all. I have a piece of 50mm steam pipe welded on a base with lugs on it that fit into the drive dogs.I just stick it in the vice for my NT30 chucks.

Originally Posted by Bryan

My MT collet chuck has spanner flats on the body and I made a simple spanner to suit. Do the NT ones not have the flats?

No flats like Ewan said. I originally made that spanner for doing up the collet chucks in the mill spindle, but found I never got enough torque on the nut, so I used to do them in the vise until I bought the fixture.

Dave