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Slipping Lathe

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Forum topic by Danpaddles posted 12-08-2012 09:13 PM 1102 views 0 times favorited 16 replies Add to Favorites Watch
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Danpaddles

539 posts in 1007 days


12-08-2012 09:13 PM

My lathe is slipping! I have a Delta Ironbed 1440. The spur drive (MT#2) is slipping worse then ever. It did some when I started to use the machine, a few years back, but I carefully smoothed out the spur drive, and the slippage was much better. It started up once, I wasted no time buying a new spur drive.

I have some pretty good grooves on the surface of the spur drive now, I once again filed/ ground off the surface roughness. Sticking my pinky finger in the drive, I feel no roughness at all.

I have also tried rubbing some bees wax on the drive, that seems to help a little, but it still spun out on me this morning while roughing out some curly maple.

Ideas? Is there a way to hone the inside of the drive? Should I shell out yet again for another new spur?

Thanks in advance for your thoughts.

-- Dan V. in Indy


16 replies so far

View David Craig's profile

David Craig

2135 posts in 1804 days


#1 posted 12-08-2012 09:47 PM

How is your belt tension? You might want to look into tightening or replacing the belt. Once they are loose, you will see the slippage you are describing.

-- There is little that is simple when it comes to making a simple box.

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Danpaddles

539 posts in 1007 days


#2 posted 12-08-2012 10:15 PM

The spur drive is slipping in the Morse taper socket. You can see where it is spinning. Plenty of power getting thru the head.

My lathe is variable speed, Reeves style pulleys. I suppose it is possible to have slippage there, but I would see the MT socket stop turning. (and I suspect at that point, I would post asking for opinions on my next lathe model!)

And yes, sometimes the spur drive slips in the wood, again, you can see where the slipping happens. For this, I either cut a little saw kerf where the drive wants to sit, or I remove the drive and hammer it into the wood. And I back off a little on the roughing gouge!

-- Dan V. in Indy

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TheDane

3877 posts in 2358 days


#3 posted 12-08-2012 10:30 PM

If you are getting groves on the Morse Taper of your spur drive then there is something (corrosion, dirt, metal filings, etc.) inside the MT of the headstock. Try cleaning it our with steel wool and some solvent.

—Gerry

-- Gerry -- "I don't plan to ever really grow up ... I'm just going to learn how to act in public!"

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TheCook

39 posts in 816 days


#4 posted 12-08-2012 10:56 PM

If you already have a chuck for your lathe then I wouldn’t bother figuring out what the story is with the MT, just throw the spur in the chuck and get back to making stuff…

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Danpaddles

539 posts in 1007 days


#5 posted 12-08-2012 11:09 PM

No chuck, sorry Cook. Nothing between me and a chuck except about $150!!

Gerry- I may just do that, but when I stick my finger in (it goes in well past the area where I have the grooves on the spur drive) it feels clean and round. Never the less, I may try your suggestion tomorrow, as it won’t cost me a thing.

The grooves I am referring to on the spur drive are similar to what a drill bit looks like after it spins in your drill press chuck. I have ground off the high points, and taken a little emery cloth to smooth it as best as I could.

-- Dan V. in Indy

View David Craig's profile

David Craig

2135 posts in 1804 days


#6 posted 12-08-2012 11:12 PM

One other thing you can try is to grind some of the end off of the center. I have the same lathe and I had a center that wouldn’t hold. I cut off about 1/4 inch off the end of the center and ground it flat. It allowed the center to go in a bit deeper and get a better hold.

-- There is little that is simple when it comes to making a simple box.

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RussellAP

2959 posts in 982 days


#7 posted 12-08-2012 11:39 PM

I have a threaded bushing that came as an adapter to my chuck that the spur drive sets in with two set screws. If it slips it’s because I didn’t tighten the tail stock enough to catch the spurs. You should try one.

-- A positive attitude will take you much further than positive thinking ever will.

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Loren

7742 posts in 2343 days


#8 posted 12-08-2012 11:43 PM

Those lathes have a reeves drive with a less than stellar
reputation. I’d take a careful look at the health of the
drive pulleys and belt.

-- http://lawoodworking.com

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Dan Krager

1617 posts in 929 days


#9 posted 12-09-2012 01:16 AM

I’ve never heard of using beeswax because it melts and becomes a lubricant under the heat generated. I think that needs to be removed thoroughly. Also check to be certain you have the right tapers trying to mate. A #2 MT will almost stick in another size, but not hold securely. There may be a slight machining deformity in the headstock. If all of those are confirmed correct, then…

+1 for shortening the taper on the spur a bit to be sure it’s not bottoming out. Hone the inside of the MT headstock and outside of the spur to be CERTAIN a uniform surface is trying to mate. Clean them well with an evaporating solvent like lacquer thinner or brake degreaser. When all that is done, insert the spur and set it home HARD with a block of wood and a mallet using great force.

DanK

-- Dan Krager, Olney IL http://www.kragerwoodworking.weebly.com

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Danpaddles

539 posts in 1007 days


#10 posted 12-09-2012 03:58 AM

David- I did some serious measuring, there is no way my spur is bottoming out. The end of the drive has a 1/2 dia., so I stuck a 1/2 drill bit in. It does not bottom out until it gets about 5/8 beyond where the spur drive sits. Russ- the slip is not (often) where the spur hits the wood. If I understand what you are describing, such a set up wouldn’t help me.

Loren- yes, I am concerned about the long term life of this lathe. There is some unhealthy looking black dust under the cover, and this is the NOISIEST lathe I have ever used. The head casting was busted when I got it, I have had to relocate the motor slightly to get it mounted. It measured square and flat where it needed to, when I got done with the work. But the noise is getting worse every year. I probably have only a few hundred hours at the most of run time. One day I will have to replace it. Part of the reason I do not want to invest in a chuck for it.

Dan K.-
And the drop that cracked the motor mount could have slightly bent the head shaft. I could try to measure the inside of the taper, maybe, and maybe even check the straightness if I still had access to a well equipped tool room. But I am not in industry anymore.

Yes, the headstock could have been machined to a slightly incorrect taper, and it could even be bent. It is a #2 though, of that I am sure.

The idea of the beeswax is that it only melts at higher temps, I thought maybe it would flow to fill gaps. Okay, bad idea. I have cleaned it all out this evening, made everything sparkle, well, as best as it could. I have not tried it out yet, that will wait for tomorrow.

I put the spur drive in my drill and ran it while rubbing with emery cloth. Tried not to overdo it, I suppose it is possible to change the taper a bit. I can not hone the head though, I can’t think what I would stick in the head to smooth it out.

BTW, setting it hard with a block and mallet goes against what I was taught about protecting the lathe bearings. They are not made to handle impact forces laterally. I’ve heard old turners say you should always remove your spur, pound it into a new workpiece on the bench, than install into the lathe. They figure it is abusing the machine to pound your workpiece onto the spur while it is in the head.

I did some google searches, found this link from an old LJ post-

http://www.youtube.com/watch?v=7HTqlefJQRo&lr=1&ob=5

he suggests this-

http://www.packardwoodworks.com/Merchant2/merchant.mvc?Screen=CTGY&Store_Code=packard&Category_Code=lathes-acc-tapacc-tapmt

that might be just what I am looking for!

thanks for the ideas. I’ll let y’all know what shakes out.

-- Dan V. in Indy

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waho6o9

5112 posts in 1272 days


#11 posted 12-09-2012 04:11 AM

Looks like I’ll be removing the spur and pounding in the new piece on
the work bench. Thanks for the friendly advice.

Instead of grinding the center of the spur, I counter sink the work
piece, and it helped a lot.

View David Craig's profile

David Craig

2135 posts in 1804 days


#12 posted 12-09-2012 04:54 AM

On my 1440, the tailstock extends after it is locked. Do you tighten the tailstock further when you are getting spin on the drive? Increased pressure from the tailstock would wedge the drive center in tighter, locking it more in place.

-- There is little that is simple when it comes to making a simple box.

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Danpaddles

539 posts in 1007 days


#13 posted 12-09-2012 05:24 AM

Yes, David, I do that, especially when the slip is occurring between the spur and the wood. It does sometimes help, in either case. I have also found the lateral tension also plays a part in chatter and harmonics. And I have a sneaking suspicion my tail stock does not clamp down on the ways as tight as it should. I really lean on the lever when I want it to tighten. I also tried tightening the cap nut under the tail stock a while back. (Might be time to do that again though…)

-- Dan V. in Indy

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David Craig

2135 posts in 1804 days


#14 posted 12-09-2012 05:33 AM

Well we ate up my list of suggestions Dan, past that, I got nothing :)

I thought maybe the material taken off the center to smooth out the grooves might have lessened the thickness, causing a bottoming out of the center, that is a negative. I thought maybe the beeswax might have over lubricated the center causing it to rotate when pressure was applied, looks like you already looked into that. And you are already reaming the tailstock for additional leverage. To me, the problem points to the drive center not being pressed in deep enough to get a good hold. Hopefully, when you clean it out, you will find a resolution. If not, I would check for any slight bends in the center.

Good luck and keep us posted.

-- There is little that is simple when it comes to making a simple box.

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REO

631 posts in 769 days


#15 posted 12-09-2012 09:20 AM

take a marker and color the spur shaft. lightly insert it into the headstock and give it a turn. see where the marker is worn off that will tell you if there is a mating problem. most machine shops have a MT reamer see if they might let you borrow it. To me it sounds as though the inside of the taper has a bur or raised spit. You should set the taper at least by launching it firmly into place. Tapping it into place with a block will not hurt the bearings. Ford originaly shipped his model “T”’s with wood inserts in the place of the wheel bearings because he thought the bearings would impact spalt. They dont under reasonable use. The noise you have could be a loose pulley especialy of there is black dust. Just a thought or two.

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