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Edward Tabachek
25th Sep 2004, 06:33 PM
Hello
It sounds as if I am going to have to replace the bearings in my Woodfast, Cobra lathe. Has anyone done this? Can you tell me if this is a difficult job, given that the Woodfast has 3 bearings with 2 together on the inboard side.

I have easily done bearings on a simpler Record lathe before, with no problems.

Thanks
Edward

gatiep
25th Sep 2004, 07:54 PM
The Record is probably worse, because the ones I have done have all had two grubscrews one after another in the same hole holding the pulley. Some good old Brittish engineering.

Can't see a problem with the Cobra.

jamesy
4th Oct 2004, 07:47 PM
Edward

If you can e'mail me your contact details, i will arrange to send you a scan of the manual.

Edward Tabachek
5th Oct 2004, 12:40 PM
Jamsey: I have the instruction booklet for the Woodfast Cobra which includes the info about replacing the bearings. I wondered if anyone else had done this job and if they had any difficulty. The instructions say to make a special drift out of brass or wood to push the shaft out, I will probably use wood and see how I make out - unless someone says that it needs to be brass.

To Jamsey or anyone else who has this lathe: Do you find it to be a smooth running machine? I also have a Woodfast M series short bed that runs a whole lot smoother and quieter than the Cobra. I have a 1 hp Leeson motor on the Cobra that seems to vibrate a little and it makes the whole lathe and stand (home built Maple wood) vibrate. Today I noticed that if I leave the knurled handle on the front of the motor mount loose the toolrest banjo and tailstock do not rattle nearly as much. The weight of the motor hangs on the belt and keeps it tight. This should be OK, eh? It seems as if the handle and that flimsy bracket transfer more vibrations to the headstock and they travel down the bed. I was in touch with another Cobra owner who said that his lathe had been modified by a previous owner who replaced the little stabilizing posts on the bed bars with solid angle brackets and that cut down on the vibes.

Edward

q9
5th Oct 2004, 01:32 PM
The belt will need a bit of slack to dampen out the vibrations, it shouldn't be pulled too tight. You should be able to tighten the knurled knob it where the motor hangs. If the belt doesn't grip with a bit of slack, then you probably need a new belt.

Maybe the motor is out of balance or the motor bearings are shot too? A motor rewind place might be worth talking to, or you can probably do the motor bearings yourself.

Edward Tabachek
5th Oct 2004, 05:26 PM
q9; Yes, I have found that a slightly slack belt transmits less vibration. I don't think the motor runs as smooth as some of my other motors. It is brand new, out of the box, but had been storred in my garage for 6 years. So I don't know if the storage affected it or if it was a sloppy product out of the factory. When I get some time I'll take the motor to a Leeson repair depot and have it checked over.
I have observed, tonight, that less vibration is transmitted to the bed and stand if that motor handle is not too tight. Maybe I can make a new bracket that attaches to the stand, instead of the headstock.
I searched the archives and found another Cobra owner that cured his vibratory problems by having the motor pulley remachined to fit the motor shaft more precisely.
Thanks
Edward

q9
5th Oct 2004, 05:46 PM
Bearings in motor could have dried out from sitting around for so long. You'll find also that having a bit of slack will assist your head bearings to last a bit longer also.

If the motor pulley doesn't fit properly, then you could probably buy a new one to fit quite cheaply. Most electrical repairers who deal with motors and machinery ie industrial stuff should be able to supply these to suit.

jamesy
5th Oct 2004, 07:06 PM
Edward

I have your same problems. I have just started to get back into turning after a long break and found the Cobra/CL does have some vibration all the way to the tool rest( made it near impossible to do some very fine cuts on a Kauri bowl I was working on). My previous lathe was a Vicmarc 200 with a 2foot belt and I got a small amount of vibration from belt whip through it but nothing like this lathe. Its a pity because the principle of the lathe appears to be ideal.

I ran the motor without the pully engaged and found that the vibration is the same as if you don't have any tension on the pulley, so my next trick is to try to isolate the motor from the lathe with some high density rubber/foam - basically do a chainsaw type thing.

I've got the CL with cast iron bed.

Edward Tabachek
10th Oct 2004, 02:57 PM
Hello: Jamesy, The last few days I have been making hollow globes for Xmas ornaments on my Cobra (twin chrome bar bed) and now with that knurled motor handle left loose the vibrating and rattling is a whole lot less (almost gone) and the turning is enjoyable again. This a significant difference from having that handle tightend.
Last March I visited the Canadian Woodfast dealer where I switched on a Cobra like yours. I was very surprised to hear and feel that machine vibrate and rattle just as much as mine. I thought perhaps the hollow pipes (bed bars) were not dampening any vibration. But here was a cast iron bed machine vibrating just as much as mine. BTW the dealer, in a previous telephone conversation, assured me that he had never seen , heard or felt a Woodfast Cobra vibrating. Either, he was streching his truth or he did not know what a smoooooooothly operating macine felt like. Other machines have the motor attached to the headstock and operate quite smooth and quiet so I wonder why this one has this problem.
I will still have to change the bearings, they whine. The faster the spindle turns, the louder the whine.
Thanks for the help Jamesy and q9
Edward

gatiep
10th Oct 2004, 03:30 PM
Edward

I would suggest you look at the following to rectify the problem.

1. Check the belt for cracks or unevenness.
2. Check the motor and spindle pulleys for runout. Maybe the pulley you fitted to your 'new' motor is not concentric on the shaft.
3. Check the motor and spindle bearings for play.
4. Check the pulleys for chip out on the V sides or something that is stuck on the side of the V surface.

The only reason the lathe runs smoother with the motor loose, is because the motor can then bounce up and down instead of transmitting the vibration to the lathe. Where I teach woodturning we have 2 Cobras and I use one as the instructors machine. Neither have any vibration.
I find the camlock on the banjo a pain with that huge handle that gets in the way. Also both machines do not auto eject the live centres. On turning the tailstock quill all the way in the handwheel on both machines jam. Not a bad lathe for turning up to medium sized bowls, but still prefer a solid cast bed.

Have a good week

:)