Countershaft very HOT.

[markba633csi]

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]

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]

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:


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]

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]

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.

 

[Rustrp]

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]

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]

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?

 

[bss1]

Try McMaster Carr.

 

[woodchucker]

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.