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Re: Harbor Freight 46199

Posted: Mon May 19, 2014 12:26 am
by Harold_V
1911ly wrote:Part #210 is probably the issue. It is a sloppy fit on the lead screw.
While you may not like the amount of lash the screw has, it isn't excessive, nor should it be of concern to you. Do not obsess on the matter. What you should concentrate on is learning to work properly with backlash, as it's a fact of life. It is neither good nor bad, it just is. Machinists who operate manual machines deal with backlash routinely.
FWIW this thing has no mileage on it. It sat since my brother bought it new. I think it has been crappy from day one.
Again, you must come to terms with the idea that it isn't "crappy". My Bridgeport mill, which I purchased new, had backlash---it was just a matter of how much. I now live with approximately .060" of lash in the table screw (the X axis) and think nothing of it. It has nothing to do with the capability of the machine to operate with precision, so long as the amount of lash is uniform over the entire screw. If it's greater in the center of travel than it is on the ends, then you have something about which to be concerned. Even then, if you use a DRO, it makes no difference.

When discussing screws on a lathe, you'd be well advised to learn to address them properly, so there's no confusion. The X-Y terminology is fallout from CNC operations, and doesn't address all of the axes you address with a lathe. For example, what would you designate the compound to be?

The main screw on a lathe is the lead screw, from which you generate threads, and possibly feeds, depending on the machine in question. It propels the carriage. Some lathes do not use the lead screw for feeds, and some use it, but not the thread, using a full length slot in the screw to drive internal gearing which propels the carriage.

The second axis is the cross slide. The screw would be referenced as the cross slide screw.

The third axis is the compound rest, and is propelled by the compound rest screw. It is often designated simply as the compound.


Re: Harbor Freight 46199

Posted: Sun Nov 29, 2015 3:24 am
by 1911ly
Oh wow, I haven't checked back on the forum (medical issues and life in general) for a bit and I am behind.

Mounting the tool post was a breeze. Just remove the old tool post and the threaded rod that runs threw the center. The BXA tool post came with a mounting plate(set it aside) and a new threaded rod.

The new rod replaces the original. Then just set the new BXA tool holder over the new post. Tight the handle down.if the handle doesn't out put handle in the right place just spin the bottom mounting plate a 180 degrees.

It's well worth it to do it. I can provide pics if needed.

Sorry about the delay. Hopefully this info will help you or someone else. Any questions just email me.

Re: Harbor Freight 46199

Posted: Sun Nov 29, 2015 7:52 am
by Torch
Sorry to hear about your medical issues.

You might want to edit your post to obscure your e-mail address to something that is still understandable to humans but less obvious to robot spiders harvesting addresses for spammers. For example, w9amr at aol period com.

Re: Harbor Freight 46199

Posted: Fri Jan 05, 2018 5:11 pm
by 1911ly
Holy resurrection of a post from the dead!

I haven't posted in several years. So I guess I am over due for a update on this issue. I figured I would update what I have found. Several years ago I decided to dig in to this a bit farther. It was also way over due for a through cleaning and a good going over. When I got the compound off the lathe bed and took a closer look at everything I figured out where most of the backlash was coming from. I noticed I could grab the hand wheel and push it in and out and move the compound. Plus (as a long on going going issue) the hand wheel would always come loose.

This gets a little long to explain and I hope this comes out right. i am not a machinist. just a hobbyist trying to learn. The lead screw has a boss that rides on the back side of the compound. On the front side is the dial, then the hand wheel fits on, then there was a split washer (manual calls for a flat) and a acorn nut to tighten things down. The hand wheel would come loose. If I tightened it very tight I could not turn the hand wheel. But hey, I had a lot less backlash :-( . I was on to something.

The manual shows it was assembled correctly less the split washer sub. To make a long story short, I tossed the split washer and replace it with a nut. I use the nut as a jam nut for the acorn nut that holds the hand wheel on. I tighten the nut and loosen it until the shaft turns free then tighten the acorn nut against it. I now have about 10 thousands play instead of 40 thousands of backlash. And the hand wheel doesn't come loose anymore!

Ideally a couple of thrust washers would be cool to have in there, one on each side of the compound. But this works way better then it was before. I can't really envision why they put a washer there in the first place and did not use a jam nut or some shim washers to take up the back lash a bit.

Here is a pic of the nut/jam nut on the hand wheel.

I have had a lot of fun with this little machine. I really have used the mill and the lathe a lot. it has not gave me any more issues. Although I do have a spindle bearing that makes a noise once in a while. I will look in to that soon. Over all, for a cheap Chinese machine I have made a lot of parts and have learned a lot.

I just picked up another lathe to tinker with. It's harbor freight 7x10. It was really really cheap. I got it from my brother. It (just like this machine) doesn't have many hours on it. I am planning on swapping the bed for a 16 inch and replacing the plastic gears with a metal set from LMS. Another fun project to play with. I am a tinkerer. So I will have a good time. I would love to have a larger machine but I don't have the room or enough of my back left to move one. I am having fun working with what I got and what I can do. That is the most important part. Just having fun. I am retired these days.

Thanks for checking out my post. I will try to get a bit more active here in the near future. I hope everyone's new year is off to a good start.

Be blessed.

Larry in South Bend.

Re: Harbor Freight 46199

Posted: Fri Jan 05, 2018 5:57 pm
by Torch
Great news Larry. Glad to hear how it worked out. Have fun with the new toy! Have you considered making your own metal gears for it?

Re: Harbor Freight 46199

Posted: Sat Jan 06, 2018 1:53 am
by 1911ly
Hello Torch. It's been a while. How are you doing?

I do not know if I have the skills to make my own. Although lack of skills hasn't always stopped me from trying something new :-). Lol. I will probably pony up and just buy a set.

Tonight I ordered new spindle bearings (taper roller type) and the tools to remove and replace them. I got the machine cheap enough that when I am done I will only have about a 100 bucks over a new one. But I will have metal gears, 16 inch bed and improved spindle bearings. And it will be a fun project.

Re: Harbor Freight 46199

Posted: Sat Jan 06, 2018 5:08 am
by pete
Hmmm, one thing to remember is that for some lathes one or more gears can sometimes be considered and designed to be sacrificial parts. There can also be a few good reasons why plastic gears may have been used. One there generaly quieter and two and I suspect this is the real reason is that during a serious crash such as running the tool into a spinning chuck jaw one of those cheaper and sacrifical parts destroys itself. Just before Myford in the UK closed it's doors one of there super 7 lathes would run in the range of about 12k-15k semi decently optioned out. They used tufnol gears for the two tumbler reverse gears. Mostly to quiet those gears while they were running but also as the cheapest part to replace in case of that crash. My Austrian built Emco uses a few plastic gears for the same reasons. The rest of the threading gears are cast iron. Still a bit weaker than steel and would be the next part to fail. And yes I did strip a couple of the plastic ones when first learning. Stripping and replacing those is far cheaper than having a full metal to metal lock up that can then destroy some far more expensive parts. Understanding why somethings designed the way it is and why certain materials are used isn't always clear or obvious. But there can be very good and proper engineering reasons for doing so. I could easily build a few steel replacement gears for my Emco but won't because of the reasons they were originaly designed into the machine.There in there to help protect my investment if I do something stupid. Most lathes also have a shear pin somewhere on the leadscrew for the same reason. Idealy that shear pin does break since it's dirt cheap and I can make an easy replcement but it doesn't always happen. When or if it doesn't then the next cheapest part is one of those plastic gears. If you can honestly say you'll never have a crash then those steel replacement gears will work fine. I do doubt there's a professional machinist around who hasn't had at least one crash and even doing there best they likely expect to have another at some point in the future.

Re: Harbor Freight 46199

Posted: Sat Jan 06, 2018 6:55 pm
by Torch
I replaced one of the shaft keys in the gear train with a copper one. Even easier and cheaper to replace than a sacrificial gear.

Re: Harbor Freight 46199

Posted: Sat Jan 06, 2018 8:18 pm
by pete
Pretty clever idea Torch and one I need to remember. After shearing the teeth on mine the first time I bought a half dozen of the 60 tooth gears that are designed to be sacrificial. Pure luck I did so because a few years after that Emco decided to quit supporting the smaller machines they were no longer building. Afaik no more parts are available for mine and never will be. If I ever do enough mistakes to use up what I have then I'm going to need to buy the correct module gear cutter, make or buy a metric keyway broach and build replacements. Your idea just might save doing that pita job.

Re: Harbor Freight 46199

Posted: Sun Jan 07, 2018 8:36 pm
by 1911ly
I agree with Pete, that an excellent ideal Torch. I will do that. Thanks for the tip!

Pete, as a rule I am pretty cautious with my stuff. I don't hog massive amounts and do my best to stay within the limits of the machine. I know there is a risk running without a sacrificial part. But parts are plentiful and pretty cheap if I do mess something up.