BT40 tool holders loose in spindle

rick-b · May 24, 2018

I just bought 35 new BT40 tool holder and pullstuds EX USA (I won’t say who they are from yet). But after trying them, I seem to have 8 to 10 which are loose in the spindle (in and out) it ranges from .001 to .020. This is my first lot of new holder I have bought is this normal? All the holder that I have been using, came with the machine and all fit tight in the spindle no problems.

Rick

HuFlungDung · May 24, 2018

Wrong pullstud, most likely.

Kaszub · May 24, 2018

Not normal, are you using your old pull studs or you got them new with holders, check the pull stud length and dia clearance, next check dia. of tapper on the holder. Do you have a tool setter with female 40 taper socket? pop them in and check distance to flange between all holders.

cwtoyota · May 24, 2018

Kaszub said:
Not normal, are you using your old pull studs or you got them new with holders, check the pull stud length and dia clearance, next check dia. of tapper on the holder. Do you have a tool setter with female 40 taper socket? pop them in and check distance to flange between all holders.

Also check the angle on the pull-studs (retention knobs). The angle under the knob is what matters and they vary between different machine tool makers. Some are 90°, some 60° and some are 45°.

Some manufacturers will include a stud drawing in the documentation with the machine, like this one from my old VMC.
(The critical angle is the 45° angle in this drawing, that's where the collet-jaws, or balls grip the stud).

rick-b · May 24, 2018

HuFlungDung said:
Wrong pullstud, most likely.

I thought that to, but I pulled one from one of my old tool holder and it didn't change.

Kaszub said:
Not normal, are you using your old pull studs or you got them new with holders, check the pull stud length and dia clearance, next check dia. of tapper on the holder. Do you have a tool setter with female 40 taper socket? pop them in and check distance to flange between all holders.

I was worried it wasn't normal. All new pullstuds, but like I said I tried some of the old pullstuds and it didn't change.I don't have my own tool setter but I can get the use of one and I will test the length.

cwtoyota said:
Also check the angle on the pull-studs (retention knobs). The angle under the knob is what matters and they vary between different machine tool makers. Some are 90°, some 60° and some are 45°.

Some manufacturers will include a stud drawing in the documentation with the machine, like this one from my old VMC.
(The critical angle is the 45° angle in this drawing, that's where the collet-jaws, or balls grip the stud).
View attachment 229262

I will check the angles, but it's funny if it's only a hand full unless I got a few odd one by mistake maybe.

MJPfin · May 25, 2018

Not by any chance a mazak machine?
Had this problem in the past, couple of tool holders seemed loose in the spindle, turned out that the gripper thread was pulled and I needed to change the whole gripper pullstud and belleville spring stack.

Marko

NAST555 · May 25, 2018

If all the holders and pullstuds "look" correct you might be in for a belleville spring washer change. The stack has to be matched correctly though to the original.
The last one I did was not fun... pulled it out and they all fell apart. Had to work with a hit and miss trial and error to get the new one's in.

fmari --MariTool- · May 25, 2018

Try loosening a retention knob and putting some kind of shim maybe .02 thick. (.5mm). The machine should still be able to clamp the tool. If not your drawbar needs more stroke. Either some washers are broken or you need to make some adjustment. This is assuming you are using the correct retention knob for your machine.

Tool holders and retention knobs have tolerances. The retention knob head to gage line relationship can deviate up to .01" of an inch. Drawbar is designed to clamp regardless.

Bobw · May 25, 2018

rick-b said:
I seem to have 8 to 10 which are loose in the spindle (in and out) it ranges from .001 to .020.

Am I reading this correctly that only CERTAIN HOLDERS are not pulling up tight in the spindle?? And
all the other tool holders, all the old ones, and most of the new ones ARE pulling up tight??
Regardless of weather they have new or old pullstuds in them??

Sounds like bad tool holders if that is the case.. You wouldn't need a fancy gage to check,
just a plate with a hole in it should work, drop the holder in and measure to the end of the
pull stud. There should be a HUGE length difference, because like Frank said, a quick and dirty
check of your bellevilles is to loosen your pullstud a bit and see if she still pulls in tight.

WAY out on a limb here, I wonder if you got some Cat40's with metric threads in them?
BT's are about .100" shorter, aren't they??? Or am I thinking backwards.

cwtoyota · May 25, 2018

Bobw said:
Am I reading this correctly that only CERTAIN HOLDERS are not pulling up tight in the spindle?? And
all the other tool holders, all the old ones, and most of the new ones ARE pulling up tight??
Regardless of weather they have new or old pullstuds in them??

Sounds like bad tool holders if that is the case.. You wouldn't need a fancy gage to check,
just a plate with a hole in it should work, drop the holder in and measure to the end of the
pull stud. There should be a HUGE length difference, because like Frank said, a quick and dirty
check of your bellevilles is to loosen your pullstud a bit and see if she still pulls in tight.

WAY out on a limb here, I wonder if you got some Cat40's with metric threads in them?
BT's are about .100" shorter, aren't they??? Or am I thinking backwards.

BT's are longer, but that length is in the flange itself. With a compatible pull-stud, CAT and BT will both go into the same BT spindle, but cannot be mixed because the tool changer will crash. (*EDIT) the CAT has a slightly longer taper too (*EDIT)

BT

CAT

fmari --MariTool- · May 25, 2018

CWToyota, No Not exactly.

BT40 has a taper height of 2.575 Inches. CAT40 is 2.687.
So a BT40 tool holder will have a retention knob with a L1 height ( knob head to retention knob flange height) @.112 longer than the same setup for CAT40. This is why a HAAS BT40 retention knob has a L1 height of 1.100 inches and a HAAS CAT40 retention knob has a L1 height of .988.

BT40 has a flange that is .360" thicker than CAT40. And the "v" is thicker.

rick-b · May 25, 2018

Bobw said:
Am I reading this correctly that only CERTAIN HOLDERS are not pulling up tight in the spindle?? And
all the other tool holders, all the old ones, and most of the new ones ARE pulling up tight??
Regardless of weather they have new or old pullstuds in them??

Sounds like bad tool holders if that is the case.. You wouldn't need a fancy gage to check,
just a plate with a hole in it should work, drop the holder in and measure to the end of the
pull stud. There should be a HUGE length difference, because like Frank said, a quick and dirty
check of your bellevilles is to loosen your pullstud a bit and see if she still pulls in tight.

WAY out on a limb here, I wonder if you got some Cat40's with metric threads in them?
BT's are about .100" shorter, aren't they??? Or am I thinking backwards.

Bobw, Your correct it's only a few that are loose. When I got the machine, I got a hole heap (58) of holder some that I use and some that look to be custom made for the job the machine was doing at the time. Everyone of them go it tight. Last month I decided to buy some new holders and pullstuds 25 go in tight 8 have from .005 to .020" in and out and 2 are.0001 to .0008.

Over the weekend I'm going pull the studs out and measure then and I will also check the threads.

rick-b · May 31, 2018

I measured the 8 loose holder, they are all longer by around .010" to .015" than the others old holder I also checked all the pullstuds and they are OK. So do I bin the new holders or can I set them up in a surface grinder and bring them to spec?

NAST555 · May 31, 2018

rick-b said:
So do I bin the new holders or can I set them up in a surface grinder and bring them to spec?

No!

You send them back if they are not up to spec and get them to replace them.

Totallyrc · May 31, 2018

rick-b said:
I measured the 8 loose holder, they are all longer by around .010" to .015" than the others old holder I also checked all the pullstuds and they are OK. So do I bin the new holders or can I set them up in a surface grinder and bring them to spec?

I would check all the new ones just to verify that they match the taper length from Franks post. (BT40 has a taper height of 2.575 Inches)If some of them are loose maybe some of them are short enough to be hand tight but will move when machining.

Mike

Vancbiker · May 31, 2018

rick-b said:
I measured the 8 loose holder, they are all longer by around .010" to .015" than the others old holder I also checked all the pullstuds and they are OK. So do I bin the new holders or can I set them up in a surface grinder and bring them to spec?

I did not see anywhere what machine these are for, but very few machines would not tightly hold a holder that was .010"-.015" too long. You would not have the correct retention force, but you would not be able to feel the tool was loose. I'm suspicious that your machine has drawbar issues.

huskermcdoogle · May 31, 2018

Vancbiker said:
I did not see anywhere what machine these are for, but very few machines would not tightly hold a holder that was .010"-.015" too long. You would not have the correct retention force, but you would not be able to feel the tool was loose. I'm suspicious that your machine has drawbar issues.

I am in on this logic as well. You need to check it with a drawbar force gage. I would be willing to be the "tight" ones will be less than 250lbs. The drawbar should likely be reading between 1500-2000 lbs. But in reality, pretty much regardless of manufacturer no less than 800 for a slow rpm spindle, no less than 1500lbs for a 10k rpm or higher spindle.

litlerob1 · May 31, 2018

C'mon OP throw them SOB's under the bus. What MTB is it. I'll go 3 to 1, it's Haas. Takers?

R

edit> never mind on the betting, I don't think Ive seen a Haas Machine with a BT Spindle. Not saying they aren't out there, just never seen one, so the Bookie isn't taking that bet.

guest · May 31, 2018

^^ They're out there. My VF-2 is BT40.

rick-b · May 31, 2018

NAST555 said:
No! You send them back if they are not up to spec and get them to replace them.

I thought that but had to ask, I checked on shipping them back but it would be cheaper to bin them and buy else were.

Totallyrc said:
I would check all the new ones just to verify that they match the taper length from Franks post. (BT40 has a taper height of 2.575 Inches)If some of them are loose maybe some of them are short enough to be hand tight but will move when machining.

Mike

I checked them against what Frank said I took 5 of the old which come with the machine they were all 65.40mm the new ones ranged from 65.58mm to 65.70mm.

Vancbiker said:
I did not see anywhere what machine these are for, but very few machines would not tightly hold a holder that was .010"-.015" too long. You would not have the correct retention force, but you would not be able to feel the tool was loose. I'm suspicious that your machine has drawbar issues.

The machine is an Extron V5AC. First off I thought that too but the fact all the ones that come with the machine and most of the new ones pullup tight and cut well made me think other wise. But now I'm thinking I will have to look around for a drawbar gauge. Who in the US has reasonably priced gauge? so far the only one I have found here is around $4500.

litlerob1 said:
C'mon OP throw them SOB's under the bus. What MTB is it. I'll go 3 to 1, it's Haas. Takers?

R

edit> never mind on the betting, I don't think Ive seen a Haas Machine with a BT Spindle. Not saying they aren't out there, just never seen one, so the Bookie isn't taking that bet.[/QUOT

Nope not a Haas, it's a Extron V5AC, can not remember the brand name they sell under in the US.

huskermcdoogle said:

I am in on this logic as well. You need to check it with a drawbar force gage. I would be willing to be the "tight" ones will be less than 250lbs. The drawbar should likely be reading between 1500-2000 lbs. But in reality, pretty much regardless of manufacturer no less than 800 for a slow rpm spindle, no less than 1500lbs for a 10k rpm or higher spindle.

Click to expand...

Like I said, that looks to be my next step. If there is a problem can I rebuild it or do I have to find some specialist ($$$$)

BT40 tool holders loose in spindle

Aluminum

Diamond

Hot Rolled

Cast Iron

Aluminum

Aluminum

Stainless

Titanium

Diamond

Cast Iron

Titanium

Aluminum

Aluminum

Stainless

Aluminum

Diamond

Stainless

Diamond

guest

Guest

Aluminum

Similar threads