Drawbar accident

[Tony Wells]

Some aftermarket drawbars come with spacers, some don't. You can make one easily, but just make sure it isn't so large it prevents the quill from extending. I have seen some with a small step that fits just inside the top hole, and that helps keep the drawbar centered.. A drawbar that is not centered can make quite a racket when you extend the spindle by rubbing the hex on the ID.

Some people may advocate just cutting off a bit of the length, but if you do that, make sure that all your tooling will receive adequate engagement. Theoretically, they are all the same if the manufacturer held to the established dimensions, but that is not always the case.

 

[ARM]

While the spring loaded sleeve certainly is workable, it may be easier to implement a spring loaded socket on a breakover. Operators won't like having to hold the wrench down to tighten/loosen the drawbar, but it will be safer.

I've only powered up a knee mill with the wrench on it (I'm partial to a box end wrench), it was in the direction that merely loosened the drawbar as soon as I turned the machine on. Of course, as stated above, the best way is to become accustomed to never letting the wrench leave your hand unless you are setting on the workbench or hanging it on a hook or something.

As far as damage, it's hard to say. The spindle is pretty robust, so it's possible that no serious damage was done. As someone else suggested, run the machine with no drawbar and an empty spindle (no tooling in the taper). If the noise is still there, and you want to make sure there is nothing going on that will build into a major breakdown, which absolutely must occur during a most critical operation, you may have to tear it down and see if the bearings are damaged. It's possible they were.

TONY WELLS Esq
Thanks for this bit of candidness.

It's just reassuring to know that we were not the only ones who were deeply concentrating on solving the problems of the job at the Vise end whilst negligently forgetting the Tool-Mounting end. Like they say...."it happens to the best of us" !!!

Be that as it may, loading a SPRING in the SOCKET is also a good solution to our quandary. Will try that out as well. This should not be too much of a hassle as there's only the Son and I sharing the machine. And he's a better, observant worker around Machinery than I am. We are all not that youthful and sprightly.

Our CRASH result was the total destruction of the Ratchet-Socket Wrench with a heavy ding on the Motor veins which U understood well as the Motor was run Clockwise to tighten into the arbour Bore. Am going down into the shop to run the machine without the DRAWBAR and any TOOLING and will let U good Folks know what she sounds like. We only hope that there was not serious damage. LW.

aRM

 

[ARM]

Some aftermarket drawbars come with spacers, some don't. You can make one easily, but just make sure it isn't so large it prevents the quill from extending. I have seen some with a small step that fits just inside the top hole, and that helps keep the drawbar centered.. A drawbar that is not centered can make quite a racket when you extend the spindle by rubbing the hex on the ID.

Some people may advocate just cutting off a bit of the length, but if you do that, make sure that all your tooling will receive adequate engagement. Theoretically, they are all the same if the manufacturer held to the established dimensions, but that is not always the case.

TONY WELLS Esq
Methinks that making a SPACER would indeed be a better idea than shortening the Bar. We could even make a few different sized ones to accommodate those idiot-syncracies that usually occur !!! Must remember however, that the Bore diameter is crucial here as well as the Drawbar diameter. Shortening and re-threading the hardened bar would be a little more difficult as it would first have to be annealed and then re-hardened, and there's no guarantee that it would remain absolutely straight after the second hardening/temper.

Once again THANK YOU, kindly for Your valuable and much appreciated inputs. It gives us much to ponder and work on without dejection.
LORD BLESS

aRM

 

[Tony Wells]

Actually, they're not all that hard. Certainly not so hard you couldn't cut threads on it. Unless the spacers you need would be ridiculously tall, that's probably the best solution, and yes, a good idea to make several of different lengths. Just make sure to use the right one.

 

[HSS]

Another solution would be to only use an open end wrench instead of a socket or box end wrench. My open end wrenches won't stay on the nut on either one of my mills if I take my hand off of them.

Patrick

 

[ARM]

......... If step pulley, its much less complicated for sure. Before you get too crazy tearing the head down looking, I would start with removing the drawbar completely, and run the machine at several speeds.
Don't forget, when doing this, remove any tooling that's in the spindle too.

................ removing the drawbar and running the machine would give you a quick yes or no real fast.

Good luck

PAUL
Sadly, seems we have done more damage than was initially anticipated.

We ran the Mill as U suggested sans Drawbar and sans Tooling in the various speeds on the Electrical Switch. Both forward and reverse. No dice. That terrible loose Bearing rattling sound still persisted. Can't describe it exactly though.

What we omitted to mention in the first post though was that the Drawbar had sunk I'd say about an inch on the second mishap. So definitely some SLEEVES or BEARING CASES may have been squashed. What do U think ???

We ran the machine in the Lower Speed Ranges moving the Levers at the side and top. Here she ran like a charm. Like her old usual self. No cranky noise. That lovely smooth swishy speed sound of the motor ONLY. !!! Changing these levers to the HIGH SPEED RANGE and Switching the starting button caused that grinding Gear Meshing for a second before she ran into full speed. We usually used our Spanner/Wrench to spin the Drawbar and mesh the Gears before starting. For this experiment we ran the changed higher speed to check what would happen, without the Drawbar being present nor turned.

In the final analysis methinks we will definitely have to get a MILLWRIGHT to open the head and thoroughly check her out, without waiting for something bigger to crash. Guess it will just have to be done 'cos we would like our machine running properly and as new.

Thanks all the same for assisting to resolve our problem.
Take Care.
aRM

 

[8ntsane]

You now have a few ways to remedy the problem. A spring stuffed in a socket is a great idea, and simple to do, with out machining any parts. The poster that said to use a open end wrench has probably the easiest solution of all. As already mentioned, the R-8 draw bar threads are 7/16 NF

As for the drawbar. They don't need to be hardened. On my own mill, I have replaced the drawbar with my own shop made draw bars. I just pick up 7/16 round stock, and thread the end with a die. I also have also milled a couple of flats in the bar so I can use set screws to lock the upper portion to the lower. I used to weld them together yrs ago, but found the heat didn't help the warping problem any.

Some people will also make the drawbar extra long on purpose. With the use of spacers, they can easily remove a spacer, then cut off the worn out thread, and the draw bar is as good as new with in minutes. I don't use the spacers on mine, but I understand why some would use that method, be it for tooling that requires it, or fast way to repair a damaged drawbar thread.

The photo posted earlier would take care of the problem if the tooling requires draw bars of different lengths, though spacers would work fine as well. One thing I have run into over the years is, finding the threads in some collets not cut as smooth as I would like. I do keep a test bolt in my tool box to check and make certain any new collet or tooling screws in without tight spots. If they don't I blow the threads out with compressed air, and retry. If the threads look good but still wont go, just run a tap through it, and should be fine. Other wise, if the thread looks bad to start with, simply return the product.

If running your machine without the drawbar and tooling still makes noises, you may have caused some damage , and need to go deeper, but hopefullt not. But as Tony says, it is possible.

Reading your last comments. Are you saying with out the draw bar, your noise has gone, except for a second when restarting after shifting to Hi range?

You should be aware that when shifting the lever positions, you should grab the spindle and be certain each move you make is locked in place. Also, I think I would run it at several lever positions, and take note of what setting creates the noise. I could be a simple adjustment, from a loose set screw , but try and look a little deeper. If you can find a online manual, it would help you understand your machine a lot better.

 

[Kennyd]

This thread reminded me of something I read a long time ago about building a safety switch for a chuck key: Chuck Key Safety Switch

Something like this could be adapted to a variety of machine tools

 

[8ntsane]

This thread reminded me of something I read a long time ago about building a safety switch for a chuck key: Chuck Key Safety Switch

Something like this could be adapted to a variety of machine tools

Kennyd

That could be just what he needs. Really, I perfer the power draw bar setup. If for any reason the PDB sticks in the down position (engaged) it will just start spinning the air tool over. Can't help but notice that. I ,like many others built it from a 3/8 drive, butterfly air gun. Some bits out of the scrap bin to a finished power draw bar for about a 100.00 total. Power draw bar could be a good project, and very inexpensive to build.

 

[jworman]

This thread reminded me of something I read a long time ago about building a safety switch for a chuck key: Chuck Key Safety Switch

Something like this could be adapted to a variety of machine tools

When I was in the Navy, so many years ago, I would often stop and visit the guys in the machine shop. One of them told me a story about going through Machinery Repair school.

If the instructor found a chuck key in a chuck, he simply removed it and dropped it into a bucket full of very old water and many many cigarette butts. If you chewed, the bucket was there for you too. It was pretty nasty.

The offender was told where his chuck key was. Almost no one offended twice.

I didn't get to go to the school (I was a boilerman) but I never forgot the story. If I even hesitate about removing the chuck key, the story comes back to me.

A bucket full of cigarette butts may be hard to find, but I'll bet an oily substance would serve as well.