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17th Jan 2014, 09:57 PM #1Intermediate Member
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- Sep 2012
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- Bomaderry NSW
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- 46
OK got that out now how do I get this off?
Gents.
You may remember a short time ago I was having all sorts of difficulty getting the morse taper fitting out of my mill? And you may remember that after some struggle I managed that?
Well now its time to get the backing plate for the chuck off my Mars lathe.
I have a chuck which bolts via three bolts onto a face place which in turn is threaded onto the lathe spindle. The chuck comes off easy. The backing plate doesnt/wont. Its been there since Adam was a boy. It appears that someone else has tried to get it off judging by the damage around the back of the collar.
I do NOT want to engage the back gears and hammer the #### out of the plate for fear of doing more damage to my back gears.
I am thinking of making up a dog that I can mount onto the plate and which I can hit with a substantial hammer without damaging the plate (which is cast by the way)
1: Is this acceptable (Hitting the plate like that)
2: Is it acceptable to warm the plate with my LPG torch (a big one), maybe packing the inside of the spindle with ice or something and then giving it a touch up with the hammer.
3: Is there any other suggestion (apart from machining the plate off the bloody lathe!)
yours in frustration
Old Hutcho
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17th Jan 2014, 10:54 PM #2Cba
- Join Date
- Aug 2007
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- Melbourne
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- 68
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- 1,410
Read all of this. Then decide what you want to try first.
Lathe - Stuck Chuck
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17th Jan 2014, 11:00 PM #3Senior Member
- Join Date
- May 2010
- Location
- rural s.a.
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- 120
Hi Old Hutcho, My face plate (not chuck back plate) locks up fairly tight on the spindle nose. My method isn't in agreement with you, but I engage the back gear, pull the face plate around to take up any backlash in the back gear & use a brass drift & club hammer to tap the faceplate loose. I have used this method ever since I have had the lathe (about 38 years) & to date there is NO damage to either the back gears or face plate. I always place the drift on the front of the plate (if it's free) as I am concerned that I will break some of the lip around the slots if I hit from the back. I use lots of moderate taps with a heavy hammer, not one all-mighty bang, this acts more like an impact wrench to loosen the plate. In your case I would give it a drink of WD40 the day before & I like your idea of some heat, not enough to damage seals but enough to expand the backing plate. I would go for just enough that you can't leave your hand on it. I don't know if your chuck back plate has slots in it but if so, the further out you can tap it the better. Hope this helps & good luck.
tinkera
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18th Jan 2014, 01:26 AM #4
Could you take photo of your headstock with the backplate please? A nice close-up toud be good.
I've had such an issue once an made a 6 foot long lever bolted on the flange I needed to unscrew. It came off without much strain and more importantly without impact on any bearings.
Your particular problem is going to be holding the spindle. Maybe you can key or shrink a solid bracket to the other end of your spindle and bolt that to the headstock somewhere?
With photos we may be able to offer some non-violent suggestions....Cheers, Joe
retired - less energy, more time to contemplate projects and more shed time....
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18th Jan 2014, 07:18 AM #5
The best penetrating oil based on a Motoring Magazines not exactly scientific, but still relevant tests are a mix of auto transmission oil and acetone. This has been discussed before. The acetone has low surface tension and draws the oil into gaps and then evaporates.
I am with Joe re the pictures, but as it would seem that the use of the gears would be risky, maybe also pictures of the other end of the spindle. You are going to need some method to stop the spindle from turning whilst applying force on the back plate.
Dean
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18th Jan 2014, 07:47 AM #6Most Valued Member
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- Jun 2007
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- sydney ( st marys )
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- 64
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- 4,887
After looking at some photos of this type of lathe,it appears that you may have reasonable access to the bull gear.
You may be able to wedge a piece of soft material between the bull gear and the headstock casting,this may allow you to lock the spindle enough to release your backing plate.
If you think that it would be better to heat the back plate 1st I would be tempted to try heating only in one spot 1st rather than heating the whole plate,I would concentrate on an area fairly close to the spindle thread and try and get it cherry red,hopefully your torch can produce enough heat quickly.
Another alternative would be to make something up that would fit over the rear spindle gear that you can clamp tight to stop the spindle turning.
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18th Jan 2014, 08:41 AM #7Most Valued Member
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- Jun 2012
- Location
- SA
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- 1,649
In a situation where it's unsafe to lock the spindle/shaft for fear of damage, a method to unscrew the chuck is to use a big rattle gun (air impact wrench) on it. This works against the mass of the object, even though it's free to turn. I've seen this method unscrew nuts on free turning camshafts without an issue.
For a lathe, you will need to make up an adpter or mount a big hexi shaft in the chuck.
RobThe worst that can happen is you will fail.
But at least you tried.
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18th Jan 2014, 09:18 AM #8Intermediate Member
- Join Date
- Sep 2012
- Location
- Bomaderry NSW
- Posts
- 46
Pictures.
Right guys I have read the stuff above and I am grateful for the suggestions. I like the idea of the long bar bolted to the plate and I also like the idea of jamming some wood or something soft in between the gears. Aurely that wont hurt the gear teeth. In the meantime, I have provided some pics which may set your imagination free.
regards
Old Hutcho
DSC00657.jpgDSC00653.jpgDSC00656.jpg
DSC00654.jpgDSC00655.jpg
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18th Jan 2014, 11:28 AM #9Most Valued Member
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If you happen to go with the method of jamming the gear ONLY PLACE THE MATERIAL UNDER THE BULL GEAR NOT BETWEEN GEARS.
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18th Jan 2014, 11:38 AM #10
stuck
I had to resort to butchery to remove the HENDEY back plate............cut it off with cut off discs and a angle grinder .........Mike
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18th Jan 2014, 12:56 PM #11Intermediate Member
- Join Date
- Sep 2012
- Location
- Bomaderry NSW
- Posts
- 46
Well. It's off! Tucked my heart firmly in my mouth and used the long bar while the back gear was engaged method. Came off surprisingly easy all things considered. Many thanks to all the guys who offered advice. The spindle thread has 4 threads and only half an inch long. So I guess I have a 8 thread per inch jobbie. Anybody like Ewan care to guess what thread it is. Might look for a new back plate to fit my drive dogs into rather than using the old one.
Regards
Old Hutcho
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18th Jan 2014, 01:14 PM #12Most Valued Member
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- Aug 2011
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- Melbourne
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- 4,779
Girl, I don't wanna know about your mild-mannered alter ego or anything like that." I mean, you tell me you're, uh, super-mega-ultra-lightning babe? That's all right with me. I'm good. I'm good.
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18th Jan 2014, 01:49 PM #13Intermediate Member
- Join Date
- Sep 2012
- Location
- Bomaderry NSW
- Posts
- 46
Thanks Simon. It is. The thread is fairly coarse and the I/ s dia of the thread is 1.5". So it will be something like 1.5 x 8?
regards
Old Hutcho
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18th Jan 2014, 02:27 PM #14Senior Member
- Join Date
- Oct 2008
- Location
- blackburn vic
- Posts
- 297
Lathe thread
My guess is 1 5/8 BSF
Roger
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18th Jan 2014, 03:10 PM #15
Hi Hutcho,
Mine is 1 1/2" 8tpi 55deg, so i guess that makes it BSF.
Well done on getting it off. I think my spindle would be the same, about 4 threads and maybe 3/8" of register.
I think you will have to make the drive plate, please correct me if i'm wrong but the Hercus/southbend noses are UNF, 60 deg, not 55deg.
Cheers,
Ew1915 17"x50" LeBlond heavy duty Lathe, 24" Queen city shaper, 1970's G Vernier FV.3.TO Universal Mill, 1958 Blohm HFS 6 surface grinder, 1942 Rivett 715 Lathe, 14"x40" Antrac Lathe, Startrite H225 Bandsaw, 1949 Hercus Camelback Drill press, 1947 Holbrook C10 Lathe.