OT - Any Bearing Experts (Thrust Problem)

One of our customers with a special three spindle drilling head is having
some problems. They went out and bought a drill press that can not get the
RPM / thrust settings right for a particular drilling process they need to
run.
Rather than buy a new drill press, they bought some tooling that can handle
the higher feed rate per revolution.
The head is being used to drill 2 holes at 0.326" diameter and one hole at
0.218" diameter. The material is stainless steel and their machine makes a
lot of thrust. They can not reduce the thrust or increase the RPM unless
they buy a new drill press and of course, they are resisting that idea
because the drill press they would need to buy (probably a used Bridgeport
actually) costs much more than the head I sold them.
The bearings inside the head do not last very long because they are being
pushed way past their thrust ratings. Because of the close C-C spacing,
there are no larger bearings or "stacked" bearing options available to me at
this time without actually building them a brand new drilling head. They
are open to this as the fault here is clear - they need the proper machine
to drive the head...
But... Before we go down either the new and more robust head route or new
machine to drive the head route... I'm wondering if there are any bearing
experts out here who can tell me whether there are any specialty bearings
that take higher thrust numbers or even vibration better than a typical ABEC
1 bearing. I was thinking ceramic, but I don't think they would take
vibration very well... We were thinking of going to higher ABEC numbers on
the bearings but I'm not sure that will help either s it shows higher RPM
ratings, but not much difference in thrust ratings.
Before anyone asks, we can't change the input/output RPM of the head to
compensate either. If I could simply have the input:output at 1:2, that
would solve it, but there is no room for the gearing inside their footprint
to do that...
Random thoughts from the wild welcomed! We have two solutions as noted
above, but the customer would like to avoid both if possible...
Regards,
Joe Agro, Jr.
(800) 871-5022
01.908.542.0244
Automatic / Pneumatic Drills:
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Spindle Drills:
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Site:
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V8013-R
Reply to
Joe AutoDrill
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======== While this does cause an increase in the motor operating temperature, if 3-phase use a VFD to slow down, i.e. 45-50 cycle. Relatively inexpensive fix if this works.
Unka' George [George McDuffee] ------------------------------------------- He that will not apply new remedies, must expect new evils: for Time is the greatest innovator: and if Time, of course, alter things to the worse, and wisdom and counsel shall not alter them to the better, what shall be the end?
Francis Bacon (1561-1626), English philosopher, essayist, statesman. Essays, "Of Innovations" (1597-1625).
Reply to
F. George McDuffee
Unfortunately, RPM and feed rates are tied to the motor RPM. We were going to throw a differetn RPM motor on there if they weren't.
Reply to
Joe AutoDrill
"Joe AutoDrill" wrote in news:CUTpl.37234$ snipped-for-privacy@newsfe20.iad:

Joe, Check with INA, they have some nice thrust/roller combination bearings that you may be able to fit in there.....worth a look....
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I'm assuming these are Angular contact bearings you are using now?
You might also look at the thin ring crossed-roller bearings they offer.....very high thrust load ratings for a very, very thin bearing. You might be able to swap to a different ABEC roller and use the crossed roller as thrust bearings in the same space.
Reply to
Anthony
I'm guessing that you're using a pair (or more) of angular contact ball bearings. Higher ABEC rated (more precise) bearings will probably last longer, just because they fit and roll better than the cheaper versions. Also, ACB's come in a variety of different contact angles, which have dramatically different characteristics in terms of how much radial or axial load they'll handle. Bigger angles give more trust (axial load) capacity, but less radial. Drilling is almost all about thrust and torque, not radial loads.
Also, if you're using more than two ACB's, you'll want to think about how they're stacked. A simple pair, arranged face to face or back to back, will carry the same axial load in either direction. But with triples or fourples, you can stack things heavy in one direction.
I'd look at improving the bearing type, rating, angle, rated capacities, and arrangement, before doing any kind of major re-design work.
KG
Reply to
Kirk Gordon
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Reply to
Bipolar Bear
In another thread he states that the spinldes are within .875" of each other. Thi is slightly more than 22 mm. The only bearings I see in the NSK catalog are deep grove ball bearings, either a 6900, or a 6801. I didn't find any Angular contact, or anything else that looks useful in that small of an OD.
The 6900 is 10mm ID, and 22mm OD The 6801 is 12mm ID, and 21mm OD.
The 6900 may have a higher load rating, if I understand it correctly.
Secondly, this appears to be a problem where they are over feeding the drill for the available RPM. So, unless the feed is mechanically driven from the spindle, it seems like a VFD could solve the problem. Since Joe says that the actual bearings in use are "Secret" not sure what more can be done for him...
Unless there are newer angular bearings, or unless he can add an Actual Thrust bearing to the face of the drive.. Don't know what else to suggest without more info.
Reply to
Half-Nutz
Random suggestion. Admittedly I have not cruised though all the posts. Have you looked into different tooling? TAlN coated parabolics - Garr Tool or Titex, 130 to 150 deg tip angle. Reduce the tool pressure and the bearings may come to you. We had excellent results in pre-hardended (RC28-35) 4130 with this style of tool, reduction of spindle loads 10-20%.
Reply to
JL
Not to be a dickhead here but 4130 at 28Rc really isn't "hardened" rather that's basically drawn back down to be only very slightly above an annealed state.
Your point ( I think ) stands though --use a high helix and split the point completely to center and IIRC your thrust req drops almost to zero....and the softer the better...
Reply to
Bipolar Bear
Good thought. With a typical "chisel" point drill, forces are about 30% torque and 70% thrust. With a good high performance drill (I'm partial to Sumitomo), the point can be split down to almost nothing, so nearly the whole thing is cutting edges instead of being so much chisel. The torque/thrust ratio can be reversed, and can often get close to 80/20. A big improvement on almost any application or machine.
KG
Reply to
Kirk Gordon
History will repeat itself : ( 1936 ) President Roosevelt signed
into law a series of large tax increases for taxpayers at all
income levels. At the bottom end, personal exemptions
were reduced, and an earned income credit was eliminated.
At the top end, the highest marginal rate was increased to
79 percent in 1936.
Between 1930 and 1940, the corporate income tax rate
was doubled from 12 percent to 24 percent, and an "excess
profits" tax was added on top. In addition, Roosevelt
imposed an excise tax on dividends, a capital stock tax,
and he increased estate taxes.
Any problem can be solved with the proper ammount of taxes.
Best Regards
Tom.
Reply to
AZOTIC
======================== When the economy is in an deflationary "death spiral" the last thing to do is increase taxes and reduce government spending as this takes even more money out of circulation, exacerbating the problem
On the other hand, an extremely skewed distribution of wealth causes other social/political problems which may outweigh the need to try to keep a reasonable amount of money in circulation through low taxes. One of the worst effects of extreme mal distribution is the isolation/insulation of a very small but very vocal/powerful minority who indeed "never had it so good," and who therefore are unwilling to tolerate, let alone promote essential changes in the economic structure/environment.
It should be noted that the accepted measure of wealth distribution is the GINI index. By this measure, the wealth/assets in the United States were more unevenly distributed [concentrated in to fewer hands] in 2007-2008 than the years 1928-29 just prior to the market break and deflation/implosion called the "Great Depression."
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you check for the relative position of the US compared to other countries remember that what is being measure is the equality of income, not the level of income. For historical US GINI data see
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Roosevelt to a *SMALL* degree did increase the marginal tax rates on those that had considerable money, but any effect on the money supply in circulation was more than offset by increased [deficit] governmental spending. At no time did he advocate the more extreme wealth redistribution schemes such as Huey Long's "Share the wealth program" under "Every Man a King."
A democratic society, indeed no society, will long endure where the social/living conditions between the elite and the bulk of the people is so extreme as to be effectively separate countries or even parallel universes. [Think "let them eat cake."]
For example, If I am making 50 million dollars a year, a spike in gasoline prices to 10$ a gallon is to my benefit because it gets the riff-raff off the roads in their cheap automobiles and lets get to my important meetings and then home quicker in my Maybach or Masseratti. Same thing in the restaurants. Expensive food keeps the yokels out of Elaine's, Ruth's Chris, or Per Lie [Windows on the World is gone] so I can get good reservations and service.
Thus in many cases, the main effect of [greatly] increased taxes, even confiscations/capital levies is not to increase governmental revenue, but to force the reconnection/reintegration of the top 1 or 2 % back into the rest of society. There will be of course howls of rage at this, but the top 1 or 2 % have only themselves to blame as they (or their employees) were the ones that drove the economic bus in the ditch, and increasingly "over the cliff."
When you are tending a flock of sheep, the whole idea is to shear them, not flay them alive, so you can keep getting the wool. FWIW -- shearing them close just before winter sets in is not a good idea ether.
Unka' George [George McDuffee] ------------------------------------------- He that will not apply new remedies, must expect new evils: for Time is the greatest innovator: and if Time, of course, alter things to the worse, and wisdom and counsel shall not alter them to the better, what shall be the end?
Francis Bacon (1561-1626), English philosopher, essayist, statesman. Essays, "Of Innovations" (1597-1625).
Reply to
F. George McDuffee
This of course added a number of years to the Great Depression, which we only got out of by entering a world war as its main manufacturing supplier
Gunner
Reply to
Gunner Asch
Agreed, after listening to the presidents speach yesterday it reminded of what roosevelt did. Being a product of chicago machine democrats i believe the president never met a tax he didnt like, same as roosevelt.
Best Regards Tom.
Reply to
AZOTIC
On Mar 1, 3:32 pm, F. George McDuffee
They learned this from Congress using the SSBN funds for general revenue. I am sure that GM put in some IOU's , just like Congress has.
Dan
Reply to
dcaster
Secret = I don't have the spec sheet near me to positively ID the bearings at this point only... 6801 is what rings a bell in my mind.
Reply to
Joe AutoDrill
I hope your bell is wrong. 6801 is an ordinary deep groove radial ball bearing. It has almost NO capacity to handle thrust loads.
KG
Reply to
Kirk Gordon
Joe, Can you add a thrust bearing ( radial rollers) to the face of the drilling head?Something like this:
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Judging from the spacing, I surmised that the bearings in use were 6800 or 6901's. Like Kirk sez.. not rated fro thrust.
Why can't they change the downfeed rate? is it fixed gearing for the downfeed, tied to the spindle? Can't they run the spindle with a VFD, to speed it up?
Reply to
Half-Nutz
You probably don't see the logical contradiction you've just stated, but on the off chance you may recognize it if it's laid out for you:
The mainstream view is that the hesitant stimulus program run by Roosevelt was proven to be insufficient to do the job. In 1935 (IIRC) he actually reversed the program and tried to re-institute a balanced budget. The result was that the recovery stopped dead in its tracks and we whipsawed into another recession.
World War II, from an economics point of view, was the greatest deficit-spending program in history. Finally, there was enough stimulus. As you say, that's what got us out of the Depression.
The lesson to be taken from this is that stimulus has to be strong and comprehensive to work. Thus, Obama's large stimulus plan, which is an outgrowth of the ill experience we had with the half-assed program of the 1930s (roughly what McCain and the Republicans are pushing for now) and the successful experience we had with the enormous stimulus of WWII.
If you think about what you said above, you'll realize what "added years to the Depression." It wasn't the deficit spending. It was the lack of it.
-- Ed Huntress
Reply to
Ed Huntress
Keep something in mind, however. The amount of national debt now is greater, in relation to GDP, than it was in 1935. So financing of such programs may become difficult.
i
Reply to
Ignoramus1554

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