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Broke my lathe, help?

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Forum topic by DonBoston posted 04-07-2016 11:05 PM 983 views 0 times favorited 21 replies Add to Favorites Watch
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DonBoston

75 posts in 926 days


04-07-2016 11:05 PM

Topic tags/keywords: broke lathe tailstock stripped toostrongformyowngood hulkwoodturner

So, I was working on a vase on my Excelsior lathe, and the tail stock was coming loose, so I cranked it back down, turned the lock level and it just spun in my hand.

Sadly, it’s not the screw that’s stripped, it’s the tail stock itself.

My current thought is to have the tail stock re-threaded a little larger, and then find a new screw which would work at a specialty shop.

Can y’all think of a better way of fixing this? I obviously can’t do anything on the lathe right now, and that’s bummin’ me out big time…

-- Don Boston RECreations by Don http://recreationsbydon.com


21 replies so far

View MrUnix's profile

MrUnix

4226 posts in 1663 days


#1 posted 04-07-2016 11:08 PM

Cheers,
Brad

-- Brad in FL - To be old and wise, you must first be young and stupid

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Clarkie

380 posts in 1305 days


#2 posted 04-07-2016 11:08 PM

Hello Don, can’t tell from the picture but do you have enough room to the right or left of where the hole is to drill and rethread. Then take the bolt and rethread that just to clean it up.

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DonBoston

75 posts in 926 days


#3 posted 04-07-2016 11:26 PM

Brad, how does that work?

Clark, I could, though the existing hole is built up (thicker) than the rest of the area.

-- Don Boston RECreations by Don http://recreationsbydon.com

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Nubsnstubs

826 posts in 1194 days


#4 posted 04-07-2016 11:34 PM

That looks like it’s the bolt that keeps the quill from spinning. It’s funny they would use the quill lock to keep the quill aligned also. Probably 1/4”, but could also be 5/16”. Can’t really tell what the threads are, but find a threading chart, and go to the next size. Keep in mind to thread using the fine threads. They hold better. If you go to 5/16 or 3/8”, go with 24 tpi. ............... Jerry (in Tucson)

-- Jerry (in Tucson)

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MrUnix

4226 posts in 1663 days


#5 posted 04-07-2016 11:47 PM

Brad, how does that work?

Look up heli-coil for instructions. Basically, you drill out the hole slightly bigger and then insert the coil. They sell kits with the coils and proper sized drill bit and tap for just about any size you may need. You will wind up with the same thread size/pitch as was there before, and the coil is much harder than the cast iron that was there, so you won’t strip it out again in the future.

Cheers,
Brad

-- Brad in FL - To be old and wise, you must first be young and stupid

View Lee's profile

Lee

51 posts in 342 days


#6 posted 04-07-2016 11:51 PM

Brad is right, a Helicoil will fix you right up, Don’t know what size you need but here’s a link to a 1/2-13 repair kit at amazon for $26. not counting the drill bit. http://www.amazon.com/Helicoil-5521-8-Coarse-Thread-Repair/dp/B0002SREOU

-- Colombia Custom woodworking

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HokieKen

1765 posts in 603 days


#7 posted 04-08-2016 12:04 AM

+3 for the helicoil. However, those external threads look pretty bad. Maybe it’s just the pic but if they look like they’re flat or rounded instead of having sharp threads, you’ll run into the same problem again eventually. Try running the handle on a nut with the same thread and see if it’s a proper fit. If not, you’ll want to address that as well.

-- Kenny, SW VA, Go Hokies!!!

View DonBoston's profile

DonBoston

75 posts in 926 days


#8 posted 04-08-2016 12:06 AM

Great, thanks y’all. I will get this sized up and order the correct size kit. And, might as well find a replacement bolt too, since it does look a little beat.

I appreciate it.

-- Don Boston RECreations by Don http://recreationsbydon.com

View HapHazzard's profile

HapHazzard

92 posts in 332 days


#9 posted 04-08-2016 12:53 AM

+1 on the helicoil. You need an 8mm x 1.25. The tapping is not as long as a standard helicoil, so when you install it, stop before the helicoil protrudes into the tailstock bore. It’s a lot easier to trim the excess off the outside. You should clean out your tapping oil and use a permanent thread lock compound to keep it in place.

-- Unix programmers never die; they just > /dev/null

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SawyerRob

33 posts in 302 days


#10 posted 04-08-2016 02:01 AM

Personally, I’d drill it out and tap it to the next size bigger, then buy a bolt for the new threads, and grind the end of it to the old size needed.

Actually, it’s quite an easy job…

SR

View MrUnix's profile

MrUnix

4226 posts in 1663 days


#11 posted 04-08-2016 02:15 AM

Personally, I’d drill it out and tap it to the next size bigger, then buy a bolt for the new threads, and grind the end of it to the old size needed.
- SawyerRob

So you would rather fab up a bolt and then have to use a wrench (or weld on a handle) to use it, instead of just using the existing locking handle? You need to drill and tap for a heli-coil anyway, so the only extra step is inserting the coil (just a few seconds). I’d rather use the existing lock handle than have to make a less functional part and fiddle with a wrench, but that’s just me :)

Cheers,
Brad

-- Brad in FL - To be old and wise, you must first be young and stupid

View Kelly's profile

Kelly

1113 posts in 2408 days


#12 posted 04-08-2016 02:22 AM

Try an auto parts store for the helicoil you need to fit your screw/bolt.

View SawyerRob's profile

SawyerRob

33 posts in 302 days


#13 posted 04-08-2016 03:02 AM

Each to their own, but if needed, I don’t mind making up a copy of an part… To me, it’s just another enjoyable project…

SR

View DonBoston's profile

DonBoston

75 posts in 926 days


#14 posted 04-08-2016 04:06 AM



+1 on the helicoil. You need an 8mm x 1.25. The tapping is not as long as a standard helicoil, so when you install it, stop before the helicoil protrudes into the tailstock bore. It s a lot easier to trim the excess off the outside. You should clean out your tapping oil and use a permanent thread lock compound to keep it in place.

- HapHazzard

Thanks for the sizing info Hap. (love your signature btw…)

-- Don Boston RECreations by Don http://recreationsbydon.com

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HapHazzard

92 posts in 332 days


#15 posted 04-09-2016 01:57 PM


Thanks for the sizing info Hap. (love your signature btw…)

- DonBoston

Thanks, and you’re welcome. Let me know if you need any help when you get to it.

I found a couple of videos on youtube that might be helpful.

1. https://youtu.be/79IYC4L68LU This guy knows what he’s doing, and he’s very thorough. He points out that the punch needs to be almost as big as the inside of the insert. That’s a very important point. One difference is that you don’t want to drive the insert in as far as he does. He’s fixing a deeper tapping in a blind hole, In your case it’s critical that the insert doesn’t extend into the bore and interfere with the quill, so you want to leave the excess on the outside and lock the insert in place so the locking screw doesn’t push it in.

2. https://youtu.be/T3I6RRHK9dE This is from Helicoil. It tells you a lot more than you need to know, but it’s interesting. They mention a type of insert called a screw-lock Helicoil. I don’t think they had these back in my machine shop days, but it might be useful here. I’d need to know if it was recommended for cast iron or only for softer metals.

-- Unix programmers never die; they just > /dev/null

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