Wide form Tool getting knocked off center

(Brown and Sharpe #2G)

I am having a problem with a 1.5" wide circular form tool for a fitting made from 1215 steel.

I know the machine it is on needed some TLC so I did the proper maintenance on it and got good results on all other tools.

The material starts at .875 O.D. and gets turned to .555
The tool chatters and gets knocked off center. I tried slowing the spindle down with no luck. I then slowed the feed down with no luck.

I had the feed and spindle speeds higher at first but before cleaning out the gibs and changing out the cam rollers. I am leaning towards increasing the feed rate due to the wide tool "grabbing" the material. I feel that the increased surface area of the tool is spreading the feed pressure out too much and isnt pushing it hard enough to force it to cut.

I have been at this for a while and was wondering if anyone had any advice.

Thanks in advance,
-Dan

That's a pretty wide tool, how is it ground (materials, clearances, etc.). Any chance you can split the tool (two arc segments) and do the cut as two plunges, with the first being the one further from the collet?

And are you sure the spindle and collet assembly is rigid, any chance the workpiece is climbing up the tool and then "banging" back down, and repeating?

If you can post some video of the cuts it might help with diagnostics.

Milland said:

That's a pretty wide tool, how is it ground (materials, clearances, etc.). Any chance you can split the tool (two arc segments) and do the cut as two plunges, with the first being the one further from the collet?

And are you sure the spindle and collet assembly is rigid, any chance the workpiece is climbing up the tool and then "banging" back down, and repeating?

If you can post some video of the cuts it might help with diagnostics.

Click to expand...

Form Tool has plenty of hook. Tried on center, little below and a little above. If its too far below it doesnt cut and just stops feeding. If its too far above it chatters and gets knocked upwards.

I have another form tool on the opposite slide. The part is 2.310" long. The form tool on the far end is about an inch wide and even though it is farther from the collet it is right on center, doesnt chatter, and gives a great finish.

The wider tool starts to chatter and make a lot of noise right as the barbs touch the material (barbed hose fitting). This is where the problem happens but doesnt chatter when the first part of the tool starts to cut. Only when the width of the tool contacts the material at the same time is when I get the issue.

I know the x-slide was in need of some maintenance and thats what I spent the last few days doing. Still no better results.

I am going to put it on the other slide and see if any changes happen.

I did have the spindle speed higher than normal with a steeper cam on it. It cut ok without knocking it off center but the finish was horrible and the tolerance was all over the place. After fixing the slide problems I got the tolerance to hold better but havent tried the faster speeds I had started with.

Im sure getting more oil on the tool wont hurt. I must say this is the widest Form tool I have used but I have seen lots more this wide on the shelf.

I guess its more trial and error. I am pretty sure I got the machine issue figured out. Now I am pretty sure its just the tool.

Another idea I have is making a carbide form tool to replace this HSS tool. I would hate to get no improved results though.

Also if I was bringing the slide in by hand it seemed to quiet down and has less chatter with the higher pressure applied. Still got knocked off center a lot though. This is why I think a higher feed rate will help

DanASM said:

Another idea I have is making a carbide form tool to replace this HSS tool. I would hate to get no improved results though.

Click to expand...

I'd delay spending money on carbide until you have a solid process.

It's been ages since I worked with automatics (like '75), and that was part of a co-op, so not trying to present myself as an expert. Getting back to the idea of splitting the tool, can you set up a slide so it cuts one segment from the front, then the second from the rear - do you have that flexibility?

You might try to do some more analysis of the slide condition, if it's still moving too much perhaps that's causing issues with cuts and finishes. Maybe get some cheap plunge indicators and set them up at a few points so you can watch the needles and see if they're stable as the slide moves or if they go berserk? Cheap because they're likely to get trashed...

The guy we had doing setups on the autos was an old dude then (perhaps late 60's), nice to know there's still people fussing with them.

Milland said:

I'd delay spending money on carbide until you have a solid process.

It's been ages since I worked with automatics (like '75), and that was part of a co-op, so not trying to present myself as an expert. Getting back to the idea of splitting the tool, can you set up a slide so it cuts one segment from the front, then the second from the rear - do you have that flexibility?

You might try to do some more analysis of the slide condition, if it's still moving too much perhaps that's causing issues with cuts and finishes. Maybe get some cheap plunge indicators and set them up at a few points so you can watch the needles and see if they're stable as the slide moves or if they go berserk? Cheap because they're likely to get trashed...

The guy we had doing setups on the autos was an old dude then (perhaps late 60's), nice to know there's still people fussing with them.

Click to expand...

I do not. Maybe if it was an ultramatic with 2 vertical slides I could do something like that. I did clean up the front slide and got much better finishes on the front form tool. After doing it to the rear I expected better results.

Ive got 15 Brownies now and can for the most part maintain all of them easily. Sometimes they end up getting put aside for a parts machine. I can only imagine how many of these ended up at the scrapyard when a simple fixed could have brought them back to life.

Ive been around them since kindergarten I am now 33. Probably the youngest guy who knows how to set up and run one of these.

Im sure I will figure it out at some point. Im going in tomorrow to try these things. I will report back

DanASM said:

Im sure I will figure it out at some point. Im going in tomorrow to try these things. I will report back

Click to expand...

Dang - 33? I can't even remember that far back...

Good luck, and please let us know if you find a fix. Still would like to see some video if that's something you can do.

camscan said:

33? I don't think I was ever that young.
Is the clamp bolt thread long enough? Is the hook clamp face in good nick? Have you tried Emery cloth between CFT and holder and also on the hook bolt? Is the gib still in adjustment when the cam is on full height?
Is this a brand new form tool made by your regular suppliers?
Before you try a flat form tool I would definitely change the tools over,this should point you in the right direction.
And now to be silly, should you be using a raising plate?

Click to expand...

I am pretty sure the bolt thread is long enough. Did not try emery cloth but the tool holder has a pin that goes in the form tool and has a plate with teeth that can be adjusted with a screw type post. (weird how with this it still gets pushed off center without jumping teeth or chipping one)

Tool from supplier of over 20+ years

Raising plate on front slide, none on back slide. I did look at this and the front slide is slightly higher than the back slide for this reason.

If I reversed direction the tool would "tighten" on the bolt and maybe not have a chance to slip. I would have to get all left handed drills and spin the spindle in reverse. I dont want to have to try this but it was a thought.

Heading to the shop now. I will report back

DanASM said:

(Brown and Sharpe #2G)

I am having a problem with a 1.5" wide circular form tool for a fitting made from 1215 steel.

I know the machine it is on needed some TLC so I did the proper maintenance on it and got good results on all other tools.

The material starts at .875 O.D. and gets turned to .555
The tool chatters and gets knocked off center. I tried slowing the spindle down with no luck. I then slowed the feed down with no luck.

I had the feed and spindle speeds higher at first but before cleaning out the gibs and changing out the cam rollers. I am leaning towards increasing the feed rate due to the wide tool "grabbing" the material. I feel that the increased surface area of the tool is spreading the feed pressure out too much and isnt pushing it hard enough to force it to cut.

I have been at this for a while and was wondering if anyone had any advice.

Thanks in advance,
-Dan

Click to expand...

Have you checked the spindle radial play.If more than about.001 I would consider adjusting the front spindle Box.
If you have never done it ,the spindle box is split and has a stack of shims that can be taken out to get the proper clearance.
I have 18 #2 and 2g from 1/2" to 2" and about a doz. is storage for back up or Parts and have been at it for 40 years . I have never used circular tools because they were not strong or ridge enough as I cut a pocket in 1018 steel up about 2" wide and up to about 3/8" deep.
I make my own cemented carbide using 1/2X3/4"1018 steel from 1/2"to about 2" wide .I use carbide Blanks 1/8" by 5/16" or 1/2" UP to 2" wide.
My tool blocks are just solid about 2"wide X about 6"LONG and about 4" tall WITH A 1/2" SLOT where the slot and tool are at proper height for the 1/2" TOOL BLANKS with a lot of set screws. I use front and rear tools the same balanced cutting. The cams front and rear are identical. I also use a bushing in a Ball Bearing holder in the Turret . My parts are 1018 have a diameter on the end with a pocket in the center that I can use the bearing support on.

Good Luck

After playing with it all day I came to the conclusion it is the back slide giving me problems. Swapped form tools out and got great results on the front slide but mixed results on the back slide.

The 1" form tool is now on the back slide furthest from the collet. The form tool that was giving me problems (1.375")is on the front slide now and its running fine.

I suspect It needs to run for half a day or so with the gib on the back slide tightened up. I ran it with a spring to pull the slide back and had mixed results. All it takes is a little chip or dirt or anything for that matter to screw it up.

I feel like taking the slide off completely and cleaning the whole damn thing out. Anyone ever do that?

Today I took the slide off and cleaned and scraped it. I didnt notice anything that looked bad/broken. After putting it all back together I made 10 parts in a row with no chatter, no howling or screaming. All in all it was a great day and this job should run very well unattended. Got it set at 60 second/cycle time. 62 parts per 12' bar. Should run nice, checking it once every hour.

Thanks for the advice everyone.

DanASM said:

Today I took the slide off and cleaned and scraped it. I didnt notice anything that looked bad/broken. After putting it all back together I made 10 parts in a row with no chatter, no howling or screaming. All in all it was a great day and this job should run very well unattended. Got it set at 60 second/cycle time. 62 parts per 12' bar. Should run nice, checking it once every hour.

Thanks for the advice everyone.

Click to expand...

Video ?....

digger doug said:

Video ?....

Click to expand...

I dont use my phone for vids or pics. I know I dont have a data plan but I may be able to record one and upload it from my pc.

Too busy right now might have to remind me.

Maybe I will make one on friday and post it this weekend. I had a phenolic cam that I made broke on me. Had to use another one that I did not like as much. I need to make another one the way I want it to be. I did get a few samples to send the customer today though. Had to ream it on my DV-59.