Very Frustrated Today...

[lukehonor]

I was getting ready to set up a job on my Tsugami BE20. This was a basic turn, drill, bore, cut off/ pick up job. My boss said it was hot and we were just waiting on material to arrive. The material was 3/4" RD. 52100 tool steel.

I had the job programmed and tooled up waiting for the material. We don't normally grind any material unless we need to hold some tight tolerances (tenths). The material arrived and I was upset to find out that the material measured up to .754"! Furthermore, it was so bent at the ends that the material wouldn't enter the guide bushing when I closed the collet! I've seen some bad material that I could work with, but this was very frustrating!

Why does material come into a shop like this? Just another day in the shop...

[SirDenisNayland]

Most tool steels come oversize. We frequently run H13 jobs (not on our swiss lathes) and the material comes as high as .015 over size. My understanding is so you can machine to .75 without needing to buy the next size up, which in tool steels depending on your source is likely to be 1"

Just another day like you said. We've given up trying to get unbent material. The guys at the mill don't give a ****, throw a sling into the middle of the bar bundle and throw it around bending it to **** without care. We even went as far as to make sure all of our material is crated to prevent bending elsewhere, but it still comes bent in the crate because well, it had to be placed in the crate at some point..
As far as bent ends go, chop off what you can. We've had to do that before, entire bundle with the last 6 inches or so of each bar bent 15 to 20 degrees.. how it happens ill never know.

Just another day as you say.

[micky316]

If material comes in bent reject it ,you only need to reject it a few times before it suddenly stops coming in bent !! thats what happens here in the UK anyway

[SirDenisNayland]

Originally Posted by micky316 If material comes in bent reject it ,you only need to reject it a few times before it suddenly stops coming in bent !! thats what happens here in the UK anyway

Thats all fine and dandy when you don't have deadlines to meet and machines to keep running!

[lukehonor]

Sir Denis Nayland,

That is a good point. I had to run the job on 2 operations and we were behind. What a pain! Next time I'll be more aware of 52100 steel. I don't know how to avoid/prevent this, other than to have the bars ground, regardless of their condition.

[hacdlux]

chop the ends past the bend and tell your supplier to send you whatever you cut off in fresh bars

i had a load of 1/4 stainless come in where the driver threw a strap over the middle and put a 4 inch bend 2 feet long in the middle of the bar. called it in and they replaced the bars and wrote off the material, we cut out the damaged section and ran it till we got the new bars the next day

.755 is actually a very comon bar size, if you have a worn/screwed up guide bushing you could probably lap it out too fit

[micky316]

Originally Posted by SirDenisNayland Thats all fine and dandy when you don't have deadlines to meet and machines to keep running!

So you send a bad job in to your customer and he accepts it just because its urgent ? ............................exactly and why should you ,deadlines or not throw it back at them a couple of times and surprise surprise it doesnt come in bent again ,problem solved, and if not change supplier

[SirDenisNayland]

Originally Posted by micky316 So you send a bad job in to your customer and he accepts it just because its urgent ? ............................exactly and why should you ,deadlines or not throw it back at them a couple of times and surprise surprise it doesnt come in bent again ,problem solved, and if not change supplier

First and foremost for the record I never send out bad parts. I resent that statement, even though I know you used it simply as an analogy for the mill sending out bad product.

Unfortunately I have no control of the material that hits the floor. I've made my complaints and voice heard, and we've held onto and rejected excessively bent material time and time again. I dont think we have much of a selection between mills, or if its my fault for actually working with the material instead of saying "no" and walking off the floor, but nothing seems to have changed and I feel I've been dealing with the same issues for years. Perhaps the costs aren't justified going to another mill, even if we get one hundred percent good bars, I really don't know.

Trust me, I know what you're saying, but sometimes you just gotta do what you gotta do and make a not so ideal situation work. You wouldn't send your kids back to the mill when they're acting up would you?

Cheers.

[statescrew]

I run tons of 52000 in all different sizes. I agree that materials these days are not as uniform as the past , however. You can ask before ordering the exact size of material prior to placing a PO. If the only material you can get happens to be OS than you might have to plan ahead and get yourself some OS guide bushings. Sometimes they are warped beyond grinding and then the only option is reject it or hit it with a form to straighten prior to the "real" machining of the part, grab it with the sub and finish it up. tricky but do-able.