Stupid Direct Drive Lathes!

[wizer]

I've been wrestling with this bloody thing for over and hour

I just can't get it out. As you can see the washer on the front of the extractor has caved in a bit and now I've run out of thread, so it just spins with the drive centre stuck fast. I've tried levering it out with a spanner wedged between the extractor and drive centre with no joy. It doesn't budge.

Any ideas? Please don't tell me I have to strip it down [-o<

I don't know why it's happening. It obviously has been fine with it's previous 2 owners. Or maybe Mike Swain never did anything between centres?

 

[loz]

I take it the jimmy in the thread protector with the spindle locked doesnt work ? - do you have a very long jimmy to use, or can extend one with soem tubing for leverage ?

Seems an odd ddesign to have a washer rather than being solid


edit ----- Just seen you have no thread left -

Is your spindle hollow ? - can you force the drive centre out from the back ?

 

[wizer]

No it's solid, direct drive.

I was jimmying it out until it popped off the thread and now just spins.

Thinking about what I said about it not happening to the previous owners. I had to drill another hole in the protector because the original one was rounded i.e I couldn't get anything to stay in there and lever. My hole is not not much better.

 

[loz]

Can you thread it back on back up to the spindle lock, then pad the gap ( between washer and prong drive with some split washers etc ? ) then use the jimmy again ?

 

[wizer]

I've just spoken to Silverdrive actually. Surprised I got through to someone. He suggested bashing it about with a bit of wood and a mallet. I'm not confident. I'll give it a go later.

 

[petercharlesfagg]

Can you thread it back on back up to the spindle lock, then pad the gap ( between washer and prong drive with some split washers etc ? ) then use the jimmy again ?

My suggestion is an open ended spanner pushed into the gap and then use the threaded section again, I use this method on my own lathe.

Peter.

PS next time a more substantial washer perhaps?

 

[jpt]

HI Tom

I helped someone with the same problem a couple of months ago what we did was screw the extractor back on part way. Then using a large wedge gently hammer it down between the extractor and the drive and it should pop out.

He has now ground a couple of flats on the extractor to take stilsons and also put glued a havier washer to it. He has not had a problem since.

john

 

[Turn It In]

Hi Tom,
As has already been said tapered wedges are the best solution. Screw the thread protector back on and measure the gap between the washer and the back of the four prong drive, you then need two pieces of steel plate that thickness. Drill a hole in the centre that is the same diameter as the shaft of the drive and saw a slot from one side to the hole on each. Next step is to file or grind the wings on either side of the slot to a wedge then they can be slotted into the gap behind the drive. Now using two lump hammers or a block of steel underneath a sharp blow on the top wedge should persuade the drive to give up.
I use a pair of wedges to release jacobs chucks from their tapers and they are usually very difficult to remove.
Best regards,
Ian.

 

[wizer]

Well I got there in the end. First I tried the guy at Silverdrive's idea of 'hitting it with a block of wood and a mallet'. After the lathe stopped laughing at me I had the same idea as PCF and used an open ended spanner between the protector and the DC. This failed too. The problem was that the protector AND the rod supplied to lever it, where too soft and kept slipping out. This caused the hole to elongate and the end of the rod to round over. :evil: As I sat looking at it in anger, I felt like hitting it. So I did. I took a rubber mallet an I gave the top of the spanner and all mighty whack! The drive centre in now buried in a pile of wood somewhere over the other side of the workshop. :roll: :wink:

Drama over. The guy at Silverdrive suggested reaming out the hole. Just a couple of turns should do it. Any views on this? I've seen plastic things that are meant to clean MT's? But I guess I need a proper reamer?

 

[Anonymous]

I'd do two things. Give the inside of the spindle a good clean out. Then I'd have a couple of flats machined onto the thread protector. That way next time you can use a spanner on it.

Actually when I was talking to Rich the other night about a similar problem he suggested those rubber strap thingies which are used to open jars of jam. Apparently aldi/lidl have cheap versions in for a few quid. If not then Axminster supposedly do a much better one.

Something like this:

Dave

 

[stevebuk]

great idea dave has, smash a jar of beetroot onto it.. :lol: :lol: :lol:

 

[Anonymous]

Yep, definitely. Then it would match his router :wink:

Dave

 

[wizer]

One of those boa constrictor things crossed my mind actually. But to be honest I think it was stuck fast and needed that whack. I might get meself one of those drive centres that goes in the chuck. Will save this bother next time.

 

[Happy amateur]

Wizer

Give Terry at Poolewood a call. He might have a thread protector that fits 1-1/2 6. I have the poolewood 1500 that uses a similar thread protector but is all one piece and does not have a washer and is steel not soft like the one you have. I would also suggest you give the MT a good clean out.

Fred

 

[wizer]

Thanks Fred, I will do just that. I had a little problem a couple of weeks back with this thing and thought then that the washer was on the limp side. Silverdrive just told me to get another washer from an engineering supply and glue it back in :roll:

If Terry can't help then I have some M33 x 3.5 bolts that I might be able to do something with.

 

[Turn It In]

Hi Tom,
Pleased to hear you showed it the way in the end. If you do decide to clean the morse taper with a machine reamer make sure you keep it aligned with the tailstock centre all the time and take very little off or you will find your taper has increased very quickly and the drive centre may not fit properly without inserting it further than the shaft will allow.
The fact that the taper lock in so well proves that the taper is a good fit. A light smear of oil on the taper after cleaning it and then wipe off with paper towel should help it not to stick when you need it apart again.
You will just have to sort out the ejector nut first.
If you need any help with engineered bit I will be happy to help.
Regards,
Ian

 

[Blister]

Tom , when you do your between center turning are you hammering the 4 prong drive center into the wood first

and then putting it on the lathe ,

or are you winding the tail stock up mega tight forcing the wood into the drive center and revolving center ?

As a previous owner :lol: I never had this problem and I did between centre turning :wink:

 

[wizer]

Nope Blister, I was turning a small dowel. 2" stock. The drive centre gets stuck even when you just push it in. I've had to use the protector to remove it without even having wood between centres. I think there is something going on with the MT. It feels rough when I stick me pinky up there

 

[paulm]

Don't know what the engineers amongst us would think about this idea :shock: , but I would wrap some wet & dry (fairly fine) around a morse taper, pop it in the hole without pushing it fully home, and give it a turn or two to ensure the MT inside is clean and smooth.

Followed with a cloth and a very small smear of light oil. You might want to skip the oil as it is after all a friction fit, but a very small and light smear wiped off after would just leave a bit of residue in the pores of the metal so it doesn't rust up too quick.

Sometimes low-tech is fine !

Other than that, as others have said, sorting out the ejector will still need to be done.

Cheers, Paul

 

[cornucopia]

Hi Tom-it might be worth checking your 4 prong drive's morse taper as somtimes when the end mushrooms over slightly they can be troublesome to get out.