8620 vs. 9310 for pull studs?

[mkd]

Just got some pricing for Bearing quality 8620 and 9310 per ams 6260 (not a Vac melt).

 they are basically the same price.

the 9310 has a higher tensile strength on paper.

 

 

Is the one steel going to be less consistent that the other? is one going to require more (mag particle) inspection than the other?

 

Sorry, totally esoteric question.

[Matthew Hajicek - Singularity]

Which one makes better knife blades out of your leftovers?

[mkd]

Which one makes better knife blades out of your leftovers?

Titanium with a carbide edge brazed on= better :-)

[Guest]

Making your own pull studs is penny-wise and pound foolish.

 

Been getting these for a year or two now and we stopped recommending any others because of issues we've had with breakage, wear and or fracturing.

http://www.jmperformanceproducts.com/

 

 

JM2CFWIW

[Newbeeee™]

Give Frank Mari @ Maritool a bell.

I would never roll my own. Too many what ifs for me and the last thing you want is one breaking and taking out a spindle or even you stood in front of the machine window... 

[mkd]

Give Frank Mari @ Maritool a bell.

I would never roll my own. Too many what ifs for me and the last thing you want is one breaking and taking out a spindle or even you stood in front of the machine window... 

i looked him up. He's slightly more expensive than USST.

[mkd]

Making your own pull studs is penny-wise and pound foolish.

 

Been getting these for a year or two now and we stopped recommending any others because of issues we've had with breakage, wear and or fracturing.

http://www.jmperformanceproducts.com/

 

 

JM2CFWIW

Thanks for the link. Never knew they existed

there's another vote for 8620.

even though 9310 has a higher tensile strength.

 

and that opinion was totally expected. I'm questioning my sanity also.

 

 

 I've never seen or heard of knob breakage without an associated crash. Would love to see how a real shop pushes machinery hard enough to call into question the pull stud.

[GoetzInd]

To be honest,I wouldn't care about the price on a pull stud as long as I had confidence in them. Especially on the thinner types like Haas and Robodrills. Not as big of a deal on the beefy ones. I just recently had one break and it set us back a lifetime worth of pull studs to replace the spindle.

 

MIke

[mkd]

To be honest,I wouldn't care about the price on a pull stud as long as I had confidence in them. Especially on the thinner types like Haas and Robodrills. Not as big of a deal on the beefy ones. I just recently had one break and it set us back a lifetime worth of pull studs to replace the spindle.

 

MIke

"Nice" thing with a Haas is the drawbar is so weak the tool will get pulled out long before the stud...lol

 

Send my your specs, i'll get you some super alloy studs with a price to match.

[MIL-TFP-41]

Just to throw another material out there, I have heard that Big Kaiser makes their pullstuds out of H-13 & rolls the threads.

Personally, JMPerformance or Nikken has never failed me.

[mkd]

Just to throw another material out there, I have heard that Big Kaiser makes their pullstuds out of H-13 & rolls the threads.

Personally, JMPerformance or Nikken has never failed me.

^^nice! H13 is what i was originally planning with. The material cost is double, so I was thinking to drop down to "good enough"

[jeff]

Just got some pricing for Bearing quality 8620 

What is "bearing quality" 8620?

[mkd]

What is "bearing quality" 8620?

I believe it is a nominally priced upgrade to commercial grade steel. I think you are more expert on modern steels.

[Guest]

...

 I've never seen or heard of knob breakage without an associated crash.

 

While crashes do certainly cause fracturing and or total failure (probably the most common cause of failure in the field), significant contributors include (but are not limited to) improper torque, bad heat treat lot, unseen micro-fracture (from failure to mag-particle inspect), corrosion (most common in Coolant Through applications), etc...

 

I witnessed first-hand two years ago several pull-stud failures at proper torque of a particular brand. Since then we have used and recommended JM Performance.

[mkd]

 bad heat treat lot,

 

I witnessed first-hand two years ago several pull-stud failures at proper torque of a particular brand. Since then we have used and recommended JM Performance.

that's right, I remember those posts now.

 

JM professes a replacement schedule of 3 years for 8hr shifts. One of their local distributor is USST. maybe i've been buying from them all along and not realizing it.

[Newbeeee™]

Thanks for the link. Never knew they existed

there's another vote for 8620.

even though 9310 has a higher tensile strength.

 

and that opinion was totally expected. I'm questioning my sanity also.

 

 

 I've never seen or heard of knob breakage without an associated crash. Would love to see how a real shop pushes machinery hard enough to call into question the pull stud.

Had 2 go on sh!tpot VS50 Hitachis at the old place.

One was a grammin error where the tool shank (facemill) rubbed and the pullstud snapped, and it took the spindle out.

The other was for a reason I can't remember, but it was within a couple of months and it also took out the spindle.

Brand new machines...

What I will say, is looking at the broken studs they looked flawed.

[jeff]

I believe it is a nominally priced upgrade to commercial grade steel. I think you are more expert on modern steels.

Maybe it's a process something like DCF? De-carb free. 

:shrug

[?Mark]

Just to throw another material out there, I have heard that Big Kaiser makes their pullstuds out of H-13 & rolls the threads.

Personally, JMPerformance or Nikken has never failed me.

 

I had several fractured Nikken pullstuds. Thankfully i caught it while in coolant thru application when I noticed leaks thru cracks. Avoided a real disaster.

 

 

+1 to JM

[mkd]

Tested with some 4340 had laying around. Sure left a crappy finish. :-(

Done in 1 op

[jaydenn]

Be careful.

I had a stud snap in my shop in 2011. The tool did in fact fall out of the spindle.

If you make your own, and something happens, who's liable?

[Newbeeee™]

...ouch

[#Rekd™]

I would never cut corners with a pull stud, saving a few dollars could cost you thousands.

 

[Machineguy]

Just so you know. 8620 can develop cracks during heat treat.  We did  a lot of shafting with 8620. All parts are 100% tested.

I would not advise using that material for pull studs. Just buy them. 

[mkd]

While I appreciate and encourage the sanity check from the naysayers, I find it rather ironic that a group of engineers and craftsmen making parts for airplanes, spaceships, etc, would universally condemn rolling your own.  IMHO, there isn't black magic involved. lol.

 Just for paranoia's sake i should be looking into a mag particle inspection kit. Anyone have experience with it?

[Matthew Hajicek - Singularity]

You must be planning on making a lot of them for it to be worth it.