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View Full Version : Noise at higher RPM's with older Enco Varispeed Mill head



DeereGuy
01-19-2007, 02:11 PM
Hi everyone, I have the chance to pick up an older Enco Mill with a varispeed head. I can get it for $500.00. Everything seems in good condition except when I cranked the speed up over 3000 RPM's, at this point I can hear a noise that maybe caused by an old belt. The spindle turns smoothly by hand so I am hoping it's just the belt. The owner says it will last me a life time but I have no experience with this type of head. If it does need rebuilt do any of you have an idea of the cost involved in parts?

I am going to take pictures of it shortly here and will post them later.

TIA

Bob

chipmaker4130
01-19-2007, 02:21 PM
I'm not specifically familiar with the Enco drive, but if it uses a single belt between two variable diameter sheaves like my Burke, a worn belt makes an odd squeak which actually resembles a dry bearing. If convenient, get the belt number and compare the new width with the current width of the installed belt. A decrease in diameter of more than 1/16 inch is enough to make it noisy. Another test is to see if the spindle speed varies over the entire range of adjustment. If it stays the same on either the slow or high end, you likely have a worn-out belt.

pcarpenter
01-19-2007, 04:10 PM
Whatcha milling at 3k rpm? ;) The point about the belt is a potential issue and about a $80 solution if that is what is wrong. If it's like the BP, you can pull the top half cover of the VS head without too terrible much difficulty. I would look for grooves worn in the VS head sheaves...if so, the parts could be a bit pricey...if running that fast is important to you.

There are lots of bearings in these variable speed heads. Nearly all but the spindle bearings are relatively inexpensive. You may want to try to locate the noise to figure out just what you are getting into. If it is one of the close copies of the BP design, you can find a BP manual on line in .pdf format that will have a cutaway diagram showing just where all the bearings lie.

I have my Bridgeport VS head mostly still apart at this point, you can email me if you wish, if you have questions.

Paul

DeereGuy
01-19-2007, 05:16 PM
Hi Chipmaker, all the speeds seem to change both in low and high range.
I can spin the spindle in neutral and it is quiet and smooth. It really sounds like a rough bearing someplace but not in the spindle and yes the drive is set up like you describe. The rest of the machine seems in good shape and the power down feed works. I will need to get a new DRO and table drive and a VFD to run the 3 hp 3 phase motor that is on it.

Here are some pics I just took of it.

http://i2.photobucket.com/albums/y39/Deere_X475guy/Machine%20Shop/P1010062.jpg

http://i2.photobucket.com/albums/y39/Deere_X475guy/Machine%20Shop/P1010061.jpg

http://i2.photobucket.com/albums/y39/Deere_X475guy/Machine%20Shop/P1010059.jpg

http://i2.photobucket.com/albums/y39/Deere_X475guy/Machine%20Shop/P1010053.jpg

Guess I will put the dovetail column mill I have on ebay this evening.

DeereGuy
01-19-2007, 05:49 PM
Whatcha milling at 3k rpm? ;) The point about the belt is a potential issue and about a $80 solution if that is what is wrong. If it's like the BP, you can pull the top half cover of the VS head without too terrible much difficulty. I would look for grooves worn in the VS head sheaves...if so, the parts could be a bit pricey...if running that fast is important to you.

There are lots of bearings in these variable speed heads. Nearly all but the spindle bearings are relatively inexpensive. You may want to try to locate the noise to figure out just what you are getting into. If it is one of the close copies of the BP design, you can find a BP manual on line in .pdf format that will have a cutaway diagram showing just where all the bearings lie.

I have my Bridgeport VS head mostly still apart at this point, you can email me if you wish, if you have questions.

Paul

Paul, guess I am not sure if I will be using it at that high of speed. Just noted that once I got above that speed it seemed to become noisy. The DRO doesn't work and neither does the added on x axis table feed. Everthing else seems to work ok and for $500.00 I will probably get it. I have looked for several years here in the mid Michigan area and haven't been able to find a decent deal on a knee mill. This one sure is beefy with lots of heavy castings.

Spin Doctor
01-19-2007, 05:51 PM
At a guess I would say the sliding pulley half on the motor shaft is worn out on the ID and the key is most likely bad too. The sliding pulley half on the output side could have bad bushings too. While have never had an Enco apart they can't be that much difference from a Bridgy. Bridgeport uses those cheap plastic sleeves as replacement parts. The new ones are only about 15 to 20 thou thick. Plus they use a key with a nylon surface on it to promote smoother motion. The one on the motor can be removed without taking the motor off IIRC. On a BP you need a couple of long #8 or 10 screws to collapse the sping in order to get the snap ring off.

Uncle O
01-19-2007, 06:28 PM
That looks like a "Well-setting " power feed for the X-axis. I have one also on my Taiwan BP clone. There doesn't seem to be any parts available for them . Mine has a stripped out bottom gear..... Odd thing is My boss had one sitting on the shelf amongst all his "Stuff" that he let me have for a real good price. Looks like New , old stock.... So if you are interested in my old one you may have it for shipping costs.....it is in bad shape but it runs. The case has been broken and repaired , but as I said it works..... you may be able to strip parts out of it to get yours running, I am in the Detroit area. Let me know if you are interested.

DeereGuy
01-19-2007, 06:48 PM
That looks like a "Well-setting " power feed for the X-axis. I have one also on my Taiwan BP clone. There doesn't seem to be any parts available for them . Mine has a stripped out bottom gear..... Odd thing is My boss had one sitting on the shelf amongst all his "Stuff" that he let me have for a real good price. Looks like New , old stock.... So if you are interested in my old one you may have it for shipping costs.....it is in bad shape but it runs. The case has been broken and repaired , but as I said it works..... you may be able to strip parts out of it to get yours running, I am in the Detroit area. Let me know if you are interested.

Uncle thanks for the offer and I sure will take you up on it if I get this one. The gears are fine on this one but they have a circuit board hanging loose. Sounds like between the two I can make a good one.:)))

I am listing my bench top dovetail mill on ebay this evening. Thats where I sold my round column one 3 years ago and I think this one will go fast. I give you a shout.

Thanks again
Bob

DeereGuy
01-19-2007, 06:50 PM
At a guess I would say the sliding pulley half on the motor shaft is worn out on the ID and the key is most likely bad too. The sliding pulley half on the output side could have bad bushings too. While have never had an Enco apart they can't be that much difference from a Bridgy. Bridgeport uses those cheap plastic sleeves as replacement parts. The new ones are only about 15 to 20 thou thick. Plus they use a key with a nylon surface on it to promote smoother motion. The one on the motor can be removed without taking the motor off IIRC. On a BP you need a couple of long #8 or 10 screws to collapse the sping in order to get the snap ring off.


Spin Doctor sounds like you have some experience with this head. Thanks for the info. After talking again with the owner a few minutes ago he and his son hadn't had the speed about 2200 in the 10 years they have had it. Like I said it is pretty quiet below the 3000 mark. I am hoping I can get by with it as is till spring.

Thanks
Bob

lane
01-19-2007, 07:04 PM
my experance with enco mills they good new feed unit $350.00 . New belts in head replace both while you in it and you may need a new bearing or two 20-30 dollars each .Know big deal. Figuare at most $600.00 for parts milllooks good 500.00 dam good price Buy it . I would even if I did not need it . $500.00 + 600.00 = $1100.00 Sell it $3500.00 good profit for a weeks work.

Forrest Addy
01-19-2007, 07:05 PM
Chances are the belt is just fine. They last a very ling time when enclosed in a case and protected against oil and dirt.

Get access to the belt and rub a little bar soap on the belt edges. The soap acts to remove the squeak and add a little stiction. Alternative a little bar soap solution shot on the pulleys and belt with a laundry squirt bottle will work but don't load the drive until the water has evaporated. A run through the speeds with the drive unloaded will help dry and spread the soap where it will do the most good.

Not a sure cure but one that's worked in automotive and industrial belts since day one.

DeereGuy
01-19-2007, 10:25 PM
I figured I would try that first Forest and thanks. I had to do that on the old PowerMatic 6 x 12 surface grinder I just got. The belt wasn't dried out but sure was noisy. A little soap fixed it right up.

Uncle O
01-22-2007, 08:05 PM
Bob,
I have tried twice to respond to your e-mail both direct and through
the boards, both have been kicked back.

So, if you come around the I-75 & I-696 area you are welcome to stop by and pick up the drive motor.

Or I can box it up and ship it to you, but I need an address.

DeereGuy
01-22-2007, 08:54 PM
Ok..not sure whats up with that. I have my mill on ebay right now and have been getting emails pretty regularly from there.


The guy I bought my Enco Mill from had a Cheviliar Mill with the head tore apart. I stopped and looked at it on my way out and the gave it to me. Its a basket case for sure but I am picking that one up also..:)))

A.K. Boomer
01-23-2007, 12:40 AM
Iv never had an enco apart or anything like that but i think Spin Doc and some of the other sugestions are good ones, One of the things i would check into is totally different though and may not be your problem because i dont think it would act up at your kind of RPM's but its worht thinking about --- the combination of "dry" non lubricated quill drive splines and belt deviation can cause anything from a rattle to a high speed chatter sound, if the belt is deviated it sends the spindle whipping at a greater speed and then de-accels, this leaves the dry splines with a fore and aft "clash" ,,, The way to test this is to apply some grease to the drive splines...

DeereGuy
01-23-2007, 09:26 PM
Guys thanks for all the suggestions! I got the Enco Mill, the Chavalier mill (basket case) and the Harig 6 x 18 grinder home today. They are all sitting on my trailer waiting for a friend with a bobcat to come sometime later this week. By time I get the VFD hooked up and electrical all ran it will be a couple of weeks. I will let everyone know what I found.

Thanks
Bob

DR
01-24-2007, 07:45 AM
In my experience with these type heads, the problem is as Spin Doc said. There's a thin plastic (Delrin?) sleeve in the expanding sheave that wears causing the problem.

It's fairly easy to fix. Take the head apart (easier said than done), machine a new sleeve. Instead of machining one yourself one of the dealers in import mills may have a replacement in stock, that head is a generic import type.


I disagree with Forrest on the idea of soap or any of the off-the-shelf belt lubricants. I have been consistently told by tech staff at belt manufacturers not to use "belt dressings". Besides, I'm sure that's not the problem here.

Spin Doctor
01-24-2007, 11:35 AM
There is one other place that can cause noise problems in a otherwise mechanically sound* Vari-Speed J type head. On a BP there is an adjustment screw right where the top casting slopes back to the motor mount area. This is the adjustment for contolling the backlash (?) in the variable speed control mechanism. If not properly set the pulleys can pulse open and closed for want of a better discription allowing the belt to slap around. With the costs of VFDs coming down I am surprised any one is selling mechanically controlled heads anymore.

*no pun intended

DeereGuy
01-24-2007, 03:13 PM
With the Chevalier Mill I also got the operation and parts manual. I was looking through it today and found where it talks about the High-Neutral-Low lever. It says that the spindle is driven by tapered clutch teeth in the high Speed/Direct Drive position. Clutch rattle will be heard if the clutch is not meshed tightly. It says to avoid this you can move the detent plate upwards.

All of this is greek to me right now. I hope once I get the equipment inside and can actually look at it closer I will figure it out. I think the Enco head probably is set up the same as this Chevalier.

If that adjustment doesn't fix it then I am hoping that I will be able to use the quiet spots in the Enco head and then just use the VFD for speed control and not have to do anything else.

Later when I get to it I will get the bearings for the Chevalier Milll and put that back together. Between this manual and this fine board I think I will probably be able to get that one back together...:)))

Thanks everyone....
Bob

DeereGuy
02-08-2007, 11:14 PM
Thought I would post an update to this thread. I finally got the Enco mill and Harig grinder in the heated part of my shop.

http://i2.photobucket.com/albums/y39/Deere_X475guy/P1010092.jpg

http://i2.photobucket.com/albums/y39/Deere_X475guy/P1010093.jpg

I ended up going with a 5hp rotary phase converter. Mostly because if there was something wrong with the head I would need to fix it sooner or later and the grinder also powers the mag chuck and electric oil pump for keeping the ways oiled. I didn't want to hack the original install and separate all the wiring out.

The major noise in the mill head turns out to be the belt. When the mill is run at the top speeds of either back gear or high gear the belt is almost ready to come off the rear varipully(not sure of correct term here) on the motor. This occurs in low gear between 440 rpm and 500 rpm. Then is quiet again untill it is up over 3500 rpm. The spindle does have .0015 movement when I pull back and forth on a 1 5/8 end mill. The spindle bearings are quiet and feel smooth when you turn the spindle with the head in neutral. I got a very nice cut with this end mill on a 1" wide crs taking a .050 depth cut. I think for now I will wait till spring to fix anything.

Thanks again everyone for you input. I know it's a crap shot trying to figure out whats wrong when all you have to go is some strangers description...:)))
I really do appreciate everyone's input.

Have fun

Bob

Uncle O
02-08-2007, 11:35 PM
Hey Bob,
I got your e-mail. My reply was kicked back again....No big deal.
I got a box for the X-feed, give me afew days and I will get it to the post office and on it's way to ya,
Kerry

DeereGuy
02-09-2007, 12:18 PM
Hey Bob,
I got your e-mail. My reply was kicked back again....No big deal.
I got a box for the X-feed, give me afew days and I will get it to the post office and on it's way to ya,
Kerry

Man...sometimes I can be pretty thick headed. I just checked the email setting for this board and I haven't had that one for a few years now. It's fixed finally and emails should come through.

Thanks Kerry!

JCHannum
02-09-2007, 12:44 PM
If the noise is only at the high end of the speed adjustment, and the belt is coming off the pulley, it is likely that the speed adjuster is not set up properly.

At the maximum speed, the belt should still be within the pulley's diameter. If it goes beyond this point, it is also possible that it is not adjusted properly on the low speed end and you are not getting the lowest speed possible. There are usually high and low limits that are adjustable to prevent over and under ranging. Take a look at this before performing major surgery.

DeereGuy
02-09-2007, 01:11 PM
If the noise is only at the high end of the speed adjustment, and the belt is coming off the pulley, it is likely that the speed adjuster is not set up properly.

At the maximum speed, the belt should still be within the pulley's diameter. If it goes beyond this point, it is also possible that it is not adjusted properly on the low speed end and you are not getting the lowest speed possible. There are usually high and low limits that are adjustable to prevent over and under ranging. Take a look at this before performing major surgery.


Jim, thanks! I have taken the side vent covers off and studied what I could see from this. I can see a stud that is mounted on the top of the casing between the motor and the drawbar. The plate inside is all the way up against the casing and there is about 3/16" of stud sticking below the plate. The stud has what appears to be a cotter key. If I adjust this screw down will it push the plate away from the top of the casing? I guess I could just give it a try this evening.