Tool Deflection?

I had to make some small spacers. They are square 4140 annealed, LxWxH is 25 mm x 13 mm x 13 mm. I was using light roughing passes with .010" stock to leave with a 1/4" 4 flute carbide. Took a finish pass at final depth, all .010" at once nice and slow. repeated finish pass. The problem is i think tool deflection. The top of the square block measures 13.13 and the bottom measures 13.24 mm, the bottom is consistently .1 mm wider. To me, this is tool deflection, but how do i eliminate this? Is 1/4" tool really too flimsy at a .75" stickout?

It could be tool deflection, or wear on the tool at the end. Measure the cutter at the top & bottom to see if there is a difference. Looking at the cutting edges with about 10X magnification can tell you a lot.

Are you using a different tool to do the finish op ?


The tool would wear the distance of your roughing DOC. so your finish pass depth should allow for this wear

Yeah, that's a lot of tool deflection. With your dimensions that's a difference of 0.11mm or 0.004" so half of that would be 0.002" - your tool deflection.

Not that I trust GW that much but it's a pretty good starting point. Entering your numbers results in the following:

https://www.cnczone.com/forums/attac...d=406298&stc=1

It's saying your expected tool deflection should be around a tenth given your parameters. So something is going on.

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Originally Posted by legacymachining

I was using light roughing passes with .010" stock to leave with a 1/4" 4 flute carbide. Took a finish pass at final depth, all .010" at once nice and slow. repeated finish pass.

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Maybe your light cuts are killing you. Annealed 4140 can work harden if you don't take a big fast cut?

Anyway, my first instinct would have been to use the biggest cutter I had. A 1/4" cutter would not have been on the list unless I was in a pinch.

My 2 cents...

Are you doing ruff and finish with the same cutter? Are you using high speed steel or carbide cutters? If you’re using high speed steel cutters, use one to ruff and one to finish. I would probably do same with carbide if I was cutting steel.

I don’t even bother with high speed steel end mills. Yes, carbide does cost more, but they last a lot longer.

I have a 3/8 3 flute carbide end mill in my machine that I’ve been running for about 2 years and it just keeps on going.

I have a couple of Inconel 718 jobs that are repeaters and I make really good money on them so I keep doing them.

I'm just asking because I don't know, but when doing a light cut would carbide deflect that much? If you must take such a light cut you might be better off with HHS because carbide seems to prefer a healthy cut, else its's just rubbing.

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Originally Posted by jttoner

I'm just asking because I don't know, but when doing a light cut would carbide deflect that much? If you must take such a light cut you might be better of with HHS because carbide seems to prefer a healthy cut, else its's just rubbing.

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It's possible to deflect depending on how sharp the cutter is. A 0.010 cut is acceptable with a carbide cutter, if the cutter is sharp.

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Originally Posted by Jim Dawson

It's possible to deflect depending on how sharp the cutter is. A 0.010 cut is acceptable with a carbide cutter, if the cutter is sharp.

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I had no idea. The carbide tools seem so rigid, but I've never tried to measure their deflection. I know the tools I use are probably not all that sharp. Unless I run them aggressively, they don't give a great finish. Maybe it's time I break down and buy some new ones. With my lathe tools it's especially important that I run them deep and fast but they are the negative inserts. On my Lagun knee mill I still use a 3" facing tool with brazed on carbide cutters that came with the old mill=drill I sold 20 years ago.. Still cuts like a hot knife through butter while giving nice blue chips.

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Originally Posted by jttoner

I had no idea. The carbide tools seem so rigid, but I've never tried to measure their deflection. I know the tools I use are probably not all that sharp. Unless I run them aggressively, they don't give a great finish. Maybe it's time I break down and buy some new ones. With my lathe tools it's especially important that I run them deep and fast but they are the negative inserts. On my Lagun knee mill I still use a 3" facing tool with brazed on carbide cutters that came with the old mill=drill I sold 20 years ago.. Still cuts like a hot knife through butter while giving nice blue chips.

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This old guy isnt too sharp anymore either ha!! Good to see you on again John.

On a more serious note, I have a Darex endmill sharpener, I touch them up with that when they begin to lose an edge. I make a lot of wood giveaway parts and it gets some use there as wood dulls cutters fairly quickly.

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Originally Posted by popspipes

This old guy isnt too sharp anymore either ha!! Good to see you on again John.

On a more serious note, I have a Darex endmill sharpener, I touch them up with that when they begin to lose an edge. I make a lot of wood giveaway parts and it gets some use there as wood dulls cutters fairly quickly.

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Again, I'd never guessed that wood would dull the tools. I'd have thought that with wood the tools would've remained sharp forever. This old dawg still trying to learn new tricks. I've never pretended to be a real machinist. I'm more like the urban cowboy with the cowboy hat but no cows :)

Those Darex machines are sweet, but wow, they cost a king's ransom. I do have one of those "Drill Doctors" for drill bits. It works fairly well for being something of a Mickey Mouse tool. Great for a home shop guy on a tight budget.

Not having any revenue work at the moment I've been focusing on maintenance, especially after the attack of Ratzilla. My organic anti-rat weapon, (a cat), is doing a great job. I've followed your lead mixing Corrosion-X with WD40. It's working out just fine. Still wish I could've gotten some of that WD41. What is your preferred ratio of WD40 to Corrosion-X? I just added some until it smelled right.

I have one of those cheapo Chinese band saws from H.F. Now they're selling for $100.00 more that I paid. I can't remember how long I've had it but it has served me well and vastly superior to my old Armstrong saw. It's another good choice for anybody just starting out with no budget .

Awhile back one of the large adjusting knobs cracked, probably from the sunlight because it's outside and exposed to the ultra violet sun rays. Yesterday I used the HF saw to cut off a piece of 3.5" o.d. steel to make a new knob for the saw. It cut like the old hot knife through butter. Then I made a really nice replacement knob for the saw with a knurled perimeter. I also made a new 12mm bolt for it with a flat for the knob's 1/4x20 grub screw. I turned the knob on my 14x40 with a negative carbide insert at max RPM, (1,600?). I milled the flat on the Tormach.

I also printed a pair of chip collectors for the Tormach. They hang over each of the drain holes on the Tormach's table. The idea is to contain the chips so the coolant is cleaner and won't clog the drain hole in the mill's stand. Another thing I printed is a four tool holder that hangs over the front edge of the stand so the operator can have five tools in order and ready for the next tool change. Five meaning one tool already in the spindle and up to four more at the ready. Because it hangs over the edge of the stand it can be placed wherever is convenient and moved or removed at any time. I also made one from 6061 that is permanently attached. Why two? The permanent one showed me I should'v made a removable one in the first place. Oh well.

I'll try to post a few photos. Might have my 6 year old g-son do it.

Thanksgiving wishes to you, yours, and all on the forum.

Quote:

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Originally Posted by jttoner

Again, I'd never guessed that wood would dull the tools. I'd have thought that with wood the tools would've remained sharp forever. This old dawg still trying to learn new tricks. I've never pretended to be a real machinist. I'm more like the urban cowboy with the cowboy hat but no cows :)

Not having any revenue work at the moment I've been focusing on maintenance, especially after the attack of Ratzilla. My organic anti-rat weapon, (a cat), is doing a great job. I've followed your lead mixing Corrosion-X with WD40. It's working out just fine. Still wish I could've gotten some of that WD41. What is your preferred ratio of WD40 to Corrosion-X? I just added some until it smelled right.

I have one of those cheapo Chinese band saws from H.F. Now they're selling for $100.00 more that I paid. I can't remember how long I've had it but it has served me well and vastly superior to my old Armstrong saw. It's another good choice for anybody just starting out with no budget .

Awhile back one of the large adjusting knobs cracked, probably from the sunlight because it's outside and exposed to the ultra violet sun rays. Yesterday I used the HF saw to cut off a piece of 3.5" o.d. steel to make a new knob for the saw. It cut like the old hot knife through butter. Then I made a really nice replacement knob for the saw with a knurled perimeter. I also made a new 12mm bolt for it with a flat for the knob's 1/4x20 grub screw. I turned the knob on my 14x40 with a negative carbide insert at max RPM, (1,600?). I milled the flat on the Tormach.

I also printed a pair of chip collectors for the Tormach. They hang over each of the drain holes on the Tormach's table. The idea is to contain the chips so the coolant is cleaner and won't clog the drain hole in the mill's stand. Another thing I printed is a four tool holder that hangs over the front edge of the stand so the operator can have five tools in order and ready for the next tool change. Five meaning one tool already in the spindle and up to four more at the ready. Because it hangs over the edge of the stand it can be placed wherever is convenient and moved or removed at any time. I also made one from 6061 that is permanently attached. Why two? The permanent one showed me I should'v made a removable one in the first place. Oh well.

I'll try to post a few photos. Might have my 6 year old g-son do it.

Thanksgiving wishes to you, yours, and all on the forum.

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Those Darex machines are sweet, but wow, they cost a king's ransom. I do have one of those "Drill Doctors" for drill bits. It works fairly well for being something of a Mickey Mouse tool. Great for a home shop guy on a tight budget.

I built 3 machines out of stainless 304 for the Dairy, It justified the Darex. and an old 1952 Bridgy...... back in 97.

Tool wear is caused by the acids in the wood, the more moisture in the wood the quicker it wears them, I only use chinese cutters now, they last as long as quality cutters but cost a whole lot less, they are giveaway parts or stay busy parts, according to the big boys down at Google ha!

Tool deflection is for real, 40 plus years in the dairy and bakery industry, 304 and 316 ss, it will teach a fellow to keep sharp tools! Aluminum is a piece of cake compared to that stuff.

I use my renishaw all the time, never dreamed it would be so popular, still has the original tip too!! The secret is that the probing routines are 95% automatic, I think thats what kills the Haimers, just too much human input.

edit: I have a 12 kv neon sign transformer that would do a number on that rat!!

In school we did some 304 with HSS tools. With sharp tools and deep cuts it wasn't too bad. I haven't broken a Haimler tip in over a year. but then I haven't
used it in over a year.

I'm finally getting the hang of CAD/CAM, but for simple 2 1/2 d I still prefer manual coding. I'm using F360 for CAD/CAM. It's Okay but two things really bug me. One is the grid just comes and goes. I'd really like it to stick around for a while. Perhaps until I finish designing. The second thing is those constraints. I wish there was an option to shut them off or at least let me decide if and where I want them. Also, they like to hide. It would be nice if I could force them to come out of hiding so I could delete the ones I don't want.

F360 really shines for printing which is something I've been doing quite bit of lately, mostly widgets for the Tormach.

When I was kid I found a neon xfmr in a pile of junk. It was a lot of fun, especially for making "Jacob's Ladders" like in the Frankenstein movies. I couldn't use it against Ratzilla b/c it would render my shop cat unemployed and she'd have to go on cat-food stamps :)

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Originally Posted by jttoner

I'm using F360 for CAD/CAM. It's Okay but two things really bug me. One is the grid just comes and goes. I'd really like it to stick around for a while. Perhaps until I finish designing. The second thing is those constraints. I wish there was an option to shut them off or at least let me decide if and where I want them. Also, they like to hide. It would be nice if I could force them to come out of hiding so I could delete the ones I don't want.

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Spend more time learning how to use it. Those things are all easily changed...

Regards,
Ray L.

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Originally Posted by SCzEngrgGroup

Spend more time learning how to use it. Those things are all easily changed...

Regards,
Ray L.

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Agreed.

Agreed -- all of those Fusion things asked by jttoner are pretty easy to set/do once you find the frickin' button that does it.
Chasing down the right button, and then memorizing it, is the main learning curve here ...

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Originally Posted by jwatte

Agreed -- all of those Fusion things asked by jttoner are pretty easy to set/do once you find the frickin' button that does it.
Chasing down the right button, and then memorizing it, is the main learning curve here ...

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That is one thing I really like about Rhino, it has buttons but you can type commands as well.

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Originally Posted by jwatte

Agreed -- all of those Fusion things asked by jttoner are pretty easy to set/do once you find the frickin' button that does it.
Chasing down the right button, and then memorizing it, is the main learning curve here ...

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I did find in the grid sub-menu a layout option that wasn't .checked. I checked it and the grid appeared but it must've been union b/c a few minutes later it disappeared. My Mickey Mouse work-around is to stop "Sketch", then select "Line". This will resuscitate the grid. Then I hit escape to kill the line line mode after which I select whatever I wanted to do and the grid remains. For the constraints I haven't found even a Mickey Mouse solution. The help menu didn't help. The tutorials, with the exception those by either Lars Christensen or Paul Mcwhorter, don't tutor. They usually just show how proficient the presenter is. Worse yet is their propensity to include annoying, dorky, or outright goofy background music that forces me to kill the sound. If I ever make a video there won't be any background music. It will be for the purpose of informing, not for entertaining. I guess that's just an old guy thing :)

I should've mentioned that it is possible to inhibit the creation of constraints by holding down the "CTRL" key, but I've found no method for disabling their automatic creation..

Quote:

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Originally Posted by jttoner

... The second thing is those constraints. I wish there was an option to shut them off or at least let me decide if and where I want them. Also, they like to hide. It would be nice if I could force them to come out of hiding so I could delete the ones I don't want...

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This may or may not still be true but under the following link dated March 2017:
https://knowledge.autodesk.com/suppo...usion-360.html

They state:
While there is no option to turn off or disable the creation of automatic sketch constraints, you may avoid them by holding the CTRL key (CMD on Mac OS).

Might not be quite what you're looking for, but if Ray has "spent more time learning how to use it" then I would hope he'd respond and explain how "those things are all easily changed" :)
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