LumberJocks

Quill came out of tailstock and won't go back in

  • Advertise with us

« back to Power Tools, Hardware and Accessories forum

Forum topic by Picken5 posted 12-13-2013 10:38 PM 711 views 0 times favorited 5 replies Add to Favorites Watch
View Picken5's profile

Picken5

124 posts in 1387 days


12-13-2013 10:38 PM

Topic tags/keywords: question lathe

Well, I think my Delta 46-700 lathe may be on its last leg – but I’m hoping someone out there in Lumberjock-land can offer a helpful tip or suggestion. Yesterday, I was turning a small block of walnut. I decided it needed a 3/8” hole in the middle of it, so I shut down the lathe, inserted my drill chuck into the tailstock, chucked up a 3/8” bit, lowered my face shield, and turned the lathe back on. I started advancing the drill bit into the work and, after it was about a half-inch in, the entire drill chuck started turning and I realized I had forgotten to lock down the quill on the tailstock. I quickly shut down the lathe but it was too late. The quill totally unscrewed itself from the tailstock. It was an interesting sight, I must confess, to see a block of walnut attached to the headstock of the lathe, with a 3/8” drill bit sticking out of it – and the bit’s still in the drill chuck, and the drill chuck is still in the quill. Quite an arrangement sticking out of a block of walnut. But the quill was no longer in the tailstock. Crap!

I thought I’d just be able to re-screw the quill back into the tailstock. But it wouldn’t go. I took the wheel off the back of the tailstock and removed the bolt that screws into the quill so I could examine it more closely. Looked fine except for what appeared to be a minor burr near the end of it. So I carefully filed that off and tried again. Keep in mind that this end of the bolt has a left-hand thread – as does the mating hole in the quill. (Not sure what the size or thread is, but it appears to be 9/16-14 – left-handed.) And, of course, the bolt has a hole drilled down its length for a knock-out bar. Well, the bolt went in about 1-1/2 rotations before it started binding. I took it apart and inspected everything again. The threads inside the quill appear to be fine – as do the rest of the threads on the bolt. But it simply won’t go back together. I thought about running the right size tap down the quill to clean up any threads I couldn’t see very well – and doing the same with the right size die on the bolt, but coming up with left-handed taps and dies isn’t easy. Fastenal offered to special order them for me, but it would take a while and cost a fortune – and I’m not even sure I’ve guessed the size correctly. I can order a new quill from Delta, but it’ll be 60 days or more before I get it, and the bolt is simply out of production. (I’ve attached a photo of the quill and bolt in case it’s useful. The longer end of the bolt is what’s supposed to thread into the quill.)

I suspected the bolt may be slightly bent, but after carefully checking that, I’ve ruled that out. Since it’s basically hollow, it occurred to me it could be twisted just enough to make the threads not work. But I’ve got no way to check that. I may have to find a machine shop to make me a new bolt for the quill, but I have no idea what that’ll cost.

I may be in the market for a new lathe — but that’s not my first choice. I’d rather fix this one. Anyone got any ideas?

-- Howard - "Time spent making sawdust is not deducted from one's lifetime." - old Scottish proverb


5 replies so far

View floyd1365's profile

floyd1365

26 posts in 543 days


#1 posted 12-13-2013 11:36 PM

heat the tailstock (not hot enough to change temper) and freeze the quill.

View Picken5's profile

Picken5

124 posts in 1387 days


#2 posted 12-14-2013 05:14 AM

Thanks Floyd. Since the actual problem is screwing the quill back onto the bolt inside the tailstock, did you actually mean that I should heat the quill and freeze the bolt?

-- Howard - "Time spent making sawdust is not deducted from one's lifetime." - old Scottish proverb

View JohnnyB's profile

JohnnyB

84 posts in 1085 days


#3 posted 12-14-2013 06:17 AM

Interesting problem. You can deal with deformed threads on the bolt by filing with a three cornered file, so you probably don’t need a die (which would be very expensive). Don’t be shy about filing away bad spots on the threads. A precision fit is not a necessity in this application. A left handed tap will clean up the threads in the quill – if you can get one (also expensive) and assuming that the threads are a standard size. From the picture, it looks like they might be Acme threads, in which case all bets are off. You might find the tap at McMaster-Carr. I would consider replacing the quill, which might not cost much more than the special tap. Also, be sure to check the key in the headstock that is supposed to keep the quill from rotating. I’m guessing that you ran the quill out to the end of its travel, and the drill kept feeding itself into the wood until the quill cleared the key and started spinning. I am going to be more careful myself when drilling deep holes on the lathe.

-- JohnnyB - - Sometimes determination can substitute for skill.

View floyd1365's profile

floyd1365

26 posts in 543 days


#4 posted 12-14-2013 04:06 PM

yea. if the threads are not messed up the problem may be a very tight tolerance. the machine has enough torque to assemble and disassemble but by hand is another story. sorry for the confusion.

View Picken5's profile

Picken5

124 posts in 1387 days


#5 posted 12-15-2013 03:48 AM

JohnnyB I’ve actually used a small triangular file on the threads of the bolt. The threads actually looked just fine, but I cleaned them anyway with the file. I then got the idea of seeing if the bolt was actually straight by chucking into the lathe’s chuck and spinning it. I reasoned that if it was bent, it would be pretty obvious once it was spinning at high speed. I had it up to 2000 RPM and it wasn’t wiggling a bit. So I guess the bolt is at least straight. And it definitely not an Acme thread on the bolt. I’m guessing the bolt is twisted—and, if floyd1365 is correct about them being a tight tolerance, a twisted bolt wouldn’t thread back into the quill very easily and it wouldn’t necessarily be visually obvious.

-- Howard - "Time spent making sawdust is not deducted from one's lifetime." - old Scottish proverb

Have your say...

You must be signed in to reply.

DISCLAIMER: Any posts on LJ are posted by individuals acting in their own right and do not necessarily reflect the views of LJ. LJ will not be held liable for the actions of any user.

Latest Projects | Latest Blog Entries | Latest Forum Topics

HomeRefurbers.com

Latest Projects | Latest Blog Entries | Latest Forum Topics

GardenTenders.com :: gardening showcase