• This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn more.
  • PLEASE: Read the FORUM RULES BEFORE registering!

Countershaft very HOT.

ThunderDog

Active Member
Active Member
#1
Let me put as much info as I can to solve what should be a simple problem.

Atlas MFB
Cutting mild steel
Using 1/2" end mill (because I don't have the original arbor...yet.)
Each pass I raise the knee (Y axis, correct?) to a depth of cut set for .010" - .015" and my Z axis(parallel direction to the spindle) is always set to .125" cut.
Tried all of the various back gear speeds (160? rpm(can't recall the setting at the moment) and 440 rpm)
Tried table feed set at .006" and .003"
I've adjusted the countershaft screws for the pulleys to the point just beyond where the belt will slip as I don't want to burn up the belt. The problem then is that I can't take but the tiniest of cuts without the belt actually slipping. So, I tried tightening the belt so I can actually take a cut. But then the countershaft bearing heats up real hot, like 150º hot measured with a infrared laser thermometer.
I checked the alignment of the countershaft pulley in relationship with the spindle pulley using a straight piece of square stock and it checked out fine. Of course, the heat is being transferred through the pulley to the spindle which measured much cooler but still hot for my liking. 90º on the spindle pulley.
Everything is oiled with Mobil Velocite #6 spindle oil.

My thoughts, just buy a new belt after work to eliminate that variable. I'm probably overthinking all of this, right?:D
This all got me thinking, what's the average depth of cut that one can expect from this machine using an end mill. I know that question has alot of variables like material being cut, type of cutter, etc. Just trying to learn this new to me machine.

Pic of what I'm talking about for clarity. The front pulley/bearing are the hot spot.
Pulleys.jpg
 

Rustrp

Active Member
Active Member
#3
What I'm seeing looks like grease on the end of the shaft, not oil? How often do you add oil or need to add oil?
 

Dave Paine

Active Member
Active Member
#4
I think you answered your own question. I would try a fixed length belt. I have link belts on a couple of woodworking machines, a jointer and drum sander. Both work well. If the belt is slipping I would try a different belt. I liked the cogged V belts even with normal pulleys since they flex easier on the smaller diameter pulleys.

I am not surprised the tight belt is causing heat. A lot of friction with a tight belt on the solid bearing shaft. If these were roller or ball bearing, they could likely take the pressure without heating up.
 

ThunderDog

Active Member
Active Member
#5
I completely disassembled and cleaned this machine and have only ever used oil. The oil ports were cleaned and cleared. Didn't they originally have some type of filter material in the oil ports to keep dirt out? Mine never had anything inside of them.

Rustrp, I thought the same thing when I started using the machine.
I was thinking, "Wow that's spewing dirty oil already? Here, let me wipe that off with my finger(machine was off, of course). WOAH, that's hot!!":eek: And then the investigation began...

I'll change the belt and post my findings later this evening.
 

woodchucker

Active Member
Active Member
#6
I completely disassembled and cleaned this machine and have only ever used oil. The oil ports were cleaned and cleared. Didn't they originally have some type of filter material in the oil ports to keep dirt out? Mine never had anything inside of them.

Rustrp, I thought the same thing when I started using the machine.
I was thinking, "Wow that's spewing dirty oil already? Here, let me wipe that off with my finger(machine was off, of course). WOAH, that's hot!!":eek: And then the investigation began...

I'll change the belt and post my findings later this evening.
Not filter material, but felt. The felt holds the oil so it gets a steady stream of oil. It wicks it down. That might be your problem, you might be slinging it out w/o a felt. You are relying on only whats there at the moment, there's no constant delivery system.
 

woodchucker

Active Member
Active Member
#8
10-4. I'll definitely add that.
Generally there are 2 ways that felts are installed. One there is a key way cut in the bearing. The felt fits in there and wicks the whole bearing length. The other is that the feed tube will have a felt installed that will hold the oil and contact the journal. That's for smaller journals. Larger use the keyway. At least from the couple of machines that I have rebuilt .
Others may have more info. See if you can get a diagram of your assembly and see how and if felts were used. If you don't have oillite bearings, chances are they need felt.
 

Silverbullet

Active Member
Active Member
#9
By looking at your pulleys there either worn badly or the belt needs to be wider 5/8" instead of 1/2". The red belt is riding way to low in the pulley . The flat of the belt should be level or a tiny bit above the pulley. Just my observation of the set up.
 

Rustrp

Active Member
Active Member
#10
I think we can put a lot of emphasis on the belts but if the belts were at issue it would be the pulley that's hot, not the end of the shaft, although you did say front pulley/shaft. If it were the belt, that's a lot of heat transfer to get the shaft hot to the touch and if so the belt should be close to smoking. Based on your comments it does seem to be a lubrication issue. I'll ask something that you've probably already checked, but with the belts off, does the shaft turn freely?
 

David S

Active User
H-M Supporter-Premium
#11
By looking at your pulleys there either worn badly or the belt needs to be wider 5/8" instead of 1/2". The red belt is riding way to low in the pulley . The flat of the belt should be level or a tiny bit above the pulley. Just my observation of the set up.
Good observation. I wonder if the belt is riding on the bottom of belt rather than the sides? And hence the need for way too much belt tension.

David
 

Silverbullet

Active Member
Active Member
#12
I think we can put a lot of emphasis on the belts but if the belts were at issue it would be the pulley that's hot, not the end of the shaft, although you did say front pulley/shaft. If it were the belt, that's a lot of heat transfer to get the shaft hot to the touch and if so the belt should be close to smoking. Based on your comments it does seem to be a lubrication issue. I'll ask something that you've probably already checked, but with the belts off, does the shaft turn freely?
I think you'll find with the belt slippage he's tightening the lever causing savere pressure on bronze bearings , there's the reason the shaft gets hotter then the pulley does . It's part of the cause and affect . With as wet as the shaft is it's oiled or greased.
 

VSAncona

Active User
Active Member
#13
I agree with Silverbullet. A 1/2" belt is too narrow. The original was closer to 5/8" wide. Clausing recommended a Gates 3280 to me for my mill.
 

Rustrp

Active Member
Active Member
#14
I think you'll find with the belt slippage he's tightening the lever causing savere pressure on bronze bearings , there's the reason the shaft gets hotter then the pulley does . It's part of the cause and affect . With as wet as the shaft is it's oiled or greased.
If the shaft was wet, as in wet...wet...wet, we would see a drop or drip, it's what #6 does. This is an adjustable link type belt and the difference of 1/8" in width doesn't change the dimensions on the side "Vee" enough that would cause the slippage or heat buildup. In regards to the position the belt is sitting in the pulley groove, we could imagine where a belt may land in a pulley if this were variable speed, so being another 1/8" higher in the pulley will only change the speed minimally without adding or taking away tractive force or effort. As a rule, a belt and pulley are sized based on the HP of the motor to insure they hold up to the physical demands of startup torque etc. and it isn't emparative for a v-belt to be sized precisely for the machine to work. With that said, I would be just as happy for TD if he says he put a 5/8" belt on and all is cool. :D
 

VSAncona

Active User
Active Member
#15
The narrow belt is an issue if it's bottoming out in the pulley because it prevents the sidewalls from gripping the pulley the way it should, which would lead to the belt slipping. If you look at the photo TD posted, you can see that the inside of the links are black from rubbing on the bottom of the pulley groove. I'm not saying that's the only possible cause, but it's where I would start.
 

Rustrp

Active Member
Active Member
#16
The narrow belt is an issue if it's bottoming out in the pulley because it prevents the sidewalls from gripping the pulley the way it should, which would lead to the belt slipping. If you look at the photo TD posted, you can see that the inside of the links are black from rubbing on the bottom of the pulley groove. I'm not saying that's the only possible cause, but it's where I would start.
If that were the case, I agree.
 

ThunderDog

Active Member
Active Member
#17
Bought a link belt for now. It's just shy of 5/8" in width.

Before we get to that I have to ask another dumb question. Do the oilite bearings have a hole to allow oil direct contact with the shaft on this thing? The oilites are impregnated with oil, right? Is that all they required, oil contact on the outside? Doesn't seem right to me. See photos below, no hole in the bearing. Paper towel for clarity. BTW, do you like the cooked and heavily scored shaft?:eek::mad::eek::mad: 20170523_231645.jpg
20170523_231433.jpg
 

Rustrp

Active Member
Active Member
#18
Bought a link belt for now. It's just shy of 5/8" in width.

Before we get to that I have to ask another dumb question. Do the oilite bearings have a hole to allow oil direct contact with the shaft on this thing? The oilites are impregnated with oil, right? Is that all they required, oil contact on the outside? Doesn't seem right to me. See photos below, no hole in the bearing. Paper towel for clarity. BTW, do you like the cooked and heavily scored shaft?:eek::mad::eek::mad: View attachment 234162
View attachment 234161
I think you just eliminated the belt as a problem. Yes, the oil needs a path to the shaft.

Edit; However dumb you may think the questions may be, you're getting smarter by the minute.:D
 

ThunderDog

Active Member
Active Member
#19
I made the cooked shaft all by my little self and learned about Oilite bearings today during play time.:D:D

I will go out on a limb and assume these were not the original bearings. The previous owner must have had a blast hacking this machine. Between the welded overarm, adding an additional set screw to the spindle pulley (different topic/different thread), etc. The list goes on.
 

Rustrp

Active Member
Active Member
#20
I made the cooked shaft all by my little self and learned about Oilite bearings today during play time.:D:D

I will go out on a limb and assume these were not the original bearings. The previous owner must have had a blast hacking this machine. Between the welded overarm, adding an additional set screw to the spindle pulley (different topic/different thread), etc. The list goes on.
Are the bearings/bushings oilite? Maybe just bronze bushings? Oilite bearings do dry out but I have used some (I forget what it is called) that have grooves machined in them along with holes located in the grooves. I have used both having spiral grooves and straight grooves in the bearings. Oilite is suppose to be self lubricating but.......?
 

markba633csi

Active Member
Active Member
#21
I don't think the link belts will transfer all the power the machine is capable of compared to a standard v belt. I've heard the link type can wear the pulleys faster too.
Mark S.
 

wa5cab

Downloads Moderator
Staff member
H-M Supporter-Premium
#22
Oilite bushings do not require an oil hole because the material itself is porous. That being said, if the bushings were changed by the PO whom you mentioned, they may not be Oilite.

The original belt on the MFB and MFC was a 5L280. I would install that as soon as you have time to pull the spindle and back gears to do so. I expect that the 1/2" link belt was slipping. However, if the pulley wasn't getting hotter than the bearing, that wasn't directly your major problem. But if it was and you tightened the belt to make up for it, you were probably putting too much side load on the bushing, causing it to overheat.

On your other question, I wish that you had included a photo of the workpiece mounted in the mill. Are you cutting on the back side with the end of the milling cutter or on the top with the side? If the former, you should be cutting with about 85% of the 1/2" diameter, not 2% or 3% of it. And technically your DOC is 1/8". I have done a lot of whittling with the milling attachment on my 3996 (because my MFA isn't running yet), and I usually use 85 to 90% of the diameter of a 5/8" or 3/4" end mill, with a DOC of 0.010" to 0.020" in mild steel or 0.050" to 0.100" in aluminum.
 

ThunderDog

Active Member
Active Member
#23
wa5cab, the bearing was the hottest point of contact. I still have the job clamped on the table, but for now while I'm at work here is a little diagram:
Work Piece.jpg

Thank you for the info. regarding the DOC. To clarify, you're saying that with end mills the amount of "side" contact of the cutter is DOC? I was using the DOC term as the amount that the knee was raised to cut a depth of .010"- .015".

Lots to learn, regardless it's a TON OF FUN!!
 

f350ca

Active User
Active Member
#24
I tried link belts on my table saw, it uses a short pair between the 3 hp motor and the arbour. I couldn't get them tight enough to not slip on all but the lightest cut. Replaced them with regular V belts and the saw was back to normal. On light loads they're probably ok but they wouldn't carry the load of the saw, but they did seem to run a little quieter.

Greg
 

Rustrp

Active Member
Active Member
#25
Oilite bushings do not require an oil hole because the material itself is porous. That being said, if the bushings were changed by the PO whom you mentioned, they may not be Oilite.
So this begs the question; Why bother with inserting any device that allows the operator to add oil to the bearing......or insert lubrication instructions in the owners manual. The service requirements of the machine in question would dictate bearing design. It's possible the bearings were changed out and it's also possible that the oil had dried up.

Oilite is designed to be self oiling but the oil does dry out. In essence they are designed to be a spounge, a hard metal composite pressed into a specific shape and size and usually only bored to size if absolutely necessary because doing so plugs the cells which move oil. Most devices that use oilite have some means of lubrication based on service, whereas oil would be added once a year, etc.

I'm being redundant here but I suppose in part it's due to the push toward the belt being the cause of the heat buildup.
 
Last edited:

Rustrp

Active Member
Active Member
#26
Oilite bushings do not require an oil hole because the material itself is porous.
Robert,

My response wasn't intended to negate and there's nothing in the parts diagram that indicates a hole exists or needs to exist. My response was half--azzzzed so my apology to you.

So this begs the question; Why bother with inserting any device that allows the operator to add oil to the bearing......or insert lubrication instructions in the owners manual.
My guess is the bearings were plugged full of gunk due to age and no oil could or would flow. It's possible the bearings were changed out with something other than oilite. This is a good educational opportunity for anyone restoring old machinery. Restoring an oilite bearing can be done but purchasing a new one is probably the best choice. The linked belt as a factor in this was probably #3 down the line in the troubleshooting flowchart. -Russ
 

bss1

H-M Supporter - Premium Content
H-M Supporter-Premium
#27
I have used link belts on a half dozen different machines. These include milling machines, lathes, and several bandsaws.

With the proper width and profile of belt for the application, I have never felt like they were more prone to slippage than a regular v belt nor do they seem to require more pressure to work. In my opinion, link belts seems to hook up so well that I wouldn't recommend them for applications where you need some slippage for safety purposes if something were to get in a bind.

It should be noted that none of my machines are used on a professional or on going daily use, but I have not observed any unusual wear on the pulleys as a result of using link belts. YMMV

The Fenner Drive link belts come in varying widths and profiles. Make sure you have the right one. If the belt is slipping or requires too much tension, it is likely the wrong size belt. Is there any oil or grease getting on the pulleys? If so, that can add to the slippage issue as well.

As the others have stated, the slippage problem may be attributable to the wrong size of belt. Get the right size and profile of belt whether it be a Link or regular v belt to eliminate that as a factor.

The heat buildup is likely due over tension of the belt and lack of lubrication. If you pulled the shaft as shown in your pic and there was not a film of oil on it, then it is going to run hot. Regardless, a bearing of this type is going to run somewhat hot due to all of the friction. You mentioned the right bearing is running at 150 degrees. Did you shoot the temp on the left bearing? Anyone know what the normal temp should be for a bearing like this?

Speed can also contribute to heat. Does it get as hot if you run with the belt in another pulley position?
 

ThunderDog

Active Member
Active Member
#28
Can't say it enough, this forum has good input from everyone and it is very beneficial for beginners like myself.

BSS1, from memory I know the bearing in the back was much cooler. I just can't recall the exact temp. With that information I did check to see if both tension screws/pins(M1-271, see pic above) were set with equal pressure.

Short of just doing a simple Google search, anybody have a good source that they have used to acquire some Oilite bearings?
 

woodchucker

Active Member
Active Member
#30
I run link belts w/o a problem on many machines, WW and metal working. I agree the right size would be important for slippage.
I looked at your paper towel and shaft. My opinion is that there is not enough oil on either. An oillite bearing would not have a hole in it. There could be a hole to it, but not a hole in it. The hole to it would be to maintain the oil level in the oillite bearing.
Since you have a hole in the bearing, I would say it was replaced by a non-oilite bearing. if so, you have 2 options. One is to try a felt wick to keep the oil flowing. You will have to oil daily (meaning 8 hours of use). Or replace the current bearing with an oillite bearing. You will still have to oil it, just very occasionally, like maybe once a month. you should have a cap on that oil hole, both wick and oilite will not prevent contamination .. light slurry or grinding dust will work it's way in and down. Order a gits cap from McMaster to keep it clean, or see the caps created by someone here using spent ammo shells (pretty cool). Any way you cap it is fine, as long as you can service it.
My thought is your bearing is a major part of the problem. But like all opinions, it's just an opinion.
I hope you realize that all of what is said by everyone is trying to help, and you are the guy at the helm. We don't get to see everything you do.. so we offer what we feel is the best info we have.
Oillite bearings are sold by McMaster Carr.