Newbie shop - 7x12 Grizzly mini-lathe cleanup

[Rayanth]

Garry, I had started by trying to follow that guide, but too many little things are different and it wasn't as easy to follow for some reason

I found http://www.mini-lathe.com/Mini_lathe/Start/start.htm which happens to be the exact lathe I purchased. It's been very easy to follow, and while I could hope for more pictures, it's been fine so far. It also goes into how to make adjustments to reduce backlash and other goodies.

- Ryan

 

[IanR]

That bit for locating the toolpost, that you nearly lost, should have a small coil spring behind it to make it pop out. Is the spring on the floor somewhere?
Ian

 

[Troutsqueezer]

Many folks leave that little locating pin out when reassembling. It can get in the way more than it helps sometimes.

 

[ProdEng]

My locating pin went in the bin on day one and now the toolpost has followed it

Jan

 

[Rayanth]

the spring behind the locating pin did not fall out. it's still springy.

pictures and all that later, but the lathe has been reassembled. ways are oiled. gears are being oiled right now but I simply couldn't resist - I fired it up on Low speed as recommended by the manual...

Alright so it's tad bit noisier than I'd anticipated, but I don't think it'll be a problem with the neighbors =)

It runs! Just a few more steps to making chips.

- get the bench drilled and bolts installed (acquired, including washers and rubber washers, hopefully enough washers to level the thing) - and leveled
- Get the bench leveled (probably before the lathe, duh)
- clean up and mount vice to bench
- clean up and mount grinder to bench

- clean up bench. what a mess... and I haven't even DONE anything!

- Ryan

 

[Grimm1966]

Congrats on the new lathe, I have the same one and it's been a hoot. I too just removed the locating pin and put it in a box with all of the other parts I don't use anymore. You will probably want to get a QCTP at some point in time and the pin will not likely work with it anyway (and because it will drive you nuts, as you can only turn the tool post clockwise).

Here is a list of things I have done to my lathe that makes working with it sooo much nicer.

1- Put a cover on the saddle gears, you will be much happier especially when you are doing a cut and the saddle jams because a piece of swarf got in the gears. Don't ask me how I know this. :

2- Install a cam-lock on the tail stock, Little Machine Shop sells a kit. It's easy to install and makes using the tailstock much, much nicer.

http://www.littlemachineshop.com/products/product_view.php?ProductID=2018&category=1070498684

3- Get a QCTP, LMS sells them too. You will want one after you spend 15 minutes trying to shim the tool bit to get it at the correct height. BTW spark plug feeler gauges work well for shims while you are waiting for the QCTP to arrive.

4- Last but definitely not least, do Rick Kruger's tapered saddle gib modification. You will need a mill (or if you have a friend with one), but it makes the machine sooo much tighter with less chatter and other problems (like having to take the saddle off to adjust the gibs).

http://warhammer.mcc.virginia.edu/ty/7x10/vault/Lathes/7x10-7x12-Projects/TaperedSaddleGibs/

Also see Bog's post on fixing up one of these lathes using Rick's modification here:

http://madmodder.net/index.php?topic=627.0

His super glued pin replacement for Rick's jig is the bees' knee's and works great! The only thing I did differently was to have two screws on either side of the tapered gib instead of the one shown in Rick's plans. Here is a picture of the modification I did on mine and shows one of the screws with a "L" bracket to keep the gib in place:

To adjust the gib you just loosen one side and snug up the other. Even after 2 years of use I still have not had to adjust it.

Good luck with the lathe, I'm sure you will have just as much fun as I have had with mine.

Jason

 

[Rayanth]

Wrapping things up, I put the lathe back together after oiling the ways with southbend way oil for lathes. Then I had to tear apart the 3-jaw, and clean it all up. that bevel gear with the spiral drive on the other side of it turned out to be a big PITA to get out, but I persevered.

All clean and dismantled, I did my best to keep everything in the same order it came out, but then remembered belatedly that I still had to put them back on in a specific order, and I never looked for numbers on the jaws. Fortunately, they were there.

Just to be sure, i ran it down after assembly to make sure the jaws came together at the same point and time.

Mounted back on the lathe, It all looks nice and shiny! Except I had to wipe down the ways and re-oil them again. I've been cleaning with kerosene, and while cleaning the 3-jaw, some kerosene splattered onto the ways, and made a really interesting pattern, but most assuredly did not do much in the way of helping the way oil do its job.

Finally I attacked the gear mess, seen in an earlier photo, and got those guys reasonably clean as well.

Sorry about the image rotation, I forgot to fix it before I uploaded.

I recalled reading something somewhere about a washer on one of the gears. I had not fully understood what was being said, but now I do. If you look at the second gear up, you'll see that both gears are inset from their respective mating gears. A washer of appropriate thickness behind the large gear (in this pic, to the right of it) will set it back into the proper alignment. Sure, the gears will work as-is, they have about 2/3 of their tooth face meshing, but I'd rather it be correct. I'll be making that change as soon as I can.

To round off my day, I put my new vise to use with the hacksaw and chopped up the stock into the lengths I'll need for the EZ engine. At least, I hope it's the lengths I will need. I intentionally went long, not knowing how straight I can cut with a hacksaw, and leaving enough to get decent facing cuts in the lathe.

I intend to try and drill the holes in the valve and piston body with the lathe, by mounting the part in the 4-jaw and the drill arbor in the tailstock. This is when it occurred to me that I'll need to remove the 3-jaw again and clean up the 4-jaw, as it won't be possible to grip square stock in the 3-jaw for facing.

As for my cats. they spent the day being lazy. They're cats. what do you expect? Furthermore, they're ragdolls - they know nothing BUT how to be lazy.

In a few hours I'll head back out and dismantle the 4-jaw for cleaning, and hopefully get the grinder unpacked and ready to make some bits.

Yes, I do intend to work on some modifications later, but right now I've had the lathe for 3 weeks, and barely even turned it on! I'm ready to make some chips, and get to know the processes before I decide what really needs fixing. The QCTP is on the list, but I've put a fair chunk of change in already with nothing to show, so it will have to wait, as other "nice-to-haves" will wait, while the"must-haves" are taken care of.

- Ryan

 

[Troutsqueezer]

IMO, an apron gear cover is a must have. After only one session of spinning brass, the carriage gears on my machine were filled with brass swarf, not a good thing. I recommend the very first thing you do is make a carriage gear chip guard.

http://www.mini-lathe.com/Mini_lathe/Modifications/modifications.htm#Chip_Guard

 

[Rayanth]

Thanks for the recommendation, Trout, as part of my first project is indeed brass... that will be something I will keep an eye on. I'm not sure I'm ready to be punching holes in my lathe already, but I might think of something.

- Ryan

 

[Tin Falcon]

ray I have to agree with trout. I have had my 7x for something like 15 years now . have not done a lot of mods but the gear cover is one I have done. I think if it was my only lathe I would do the carriage lock and lever tail stock lock.
I understand not wanting to drill holes in a new machine or an old one Like my 1937 south bend . but IMHO many of the mods that people do to the minis are things the factory should have done but do not do because they are pumping them out by the hundred and want to keep the cost affordable for the hobby .So we get nice little affordable preassembled kits that need diassembly cleaning deburring adjusting and addition of parts and features that are real nice to have and are standard on real lathes. (whatever that is) the point being is make that little 7x into the lathe you want. Improving it will improve its value.
tin

 

[Grimm1966]

Thanks for the recommendation, Trout, as part of my first project is indeed brass... that will be something I will keep an eye on. I'm not sure I'm ready to be punching holes in my lathe already, but I might think of something.

- Ryan

I understand, I felt the same way. But, as trout said, you will get swarf in the gears. At the very least you should try taping some card stock over them as a temporary measure, that way you can use the lathe without worrying about the gears getting jammed.

Jason

 

[Rayanth]

Will look into a temporary workaround. Don't have a drill press or mill, or immediate access to one, so don't even have a method of a permanent solution just yet.

- Ryan

 

[Rayanth]

So, the more I look into the various mods, the more of them I want to do. Sadly many of them require a mill, so those are all off the table for now. Any that require a drill press *might* be doable in the near future - my contact at work is back from his trip to france, and still has a tabletop drill press he received as partial payment for something that he wishes to part with for $50. I probably still need a vise for it, but it's a start.

My question at the moment involves a possible workaround for a mini-lathe shortcoming. There is no carriage lock. while there are some easy quick fixes, they have their drawbacks, and the more 'correct' quick fixes are a bit beyond my current skill range and tooling.

But, I think I may have stumbled on a temporary solution. provided the top slide's angle isn't needed for something else, and I need the carriage locked for some good cuts, would it be feasible to simply disengage the lever that allows the gears to drive the leadscrew ( so it isn't turning), lock the carriage into the leadscrew, and then use an angle to the top slide, to get my left/right in the right place (since the leadscrew won't allow perfect placement) ? Seems this would stop the carriage from moving, because it's trying to be driven by a worm gear that isn't turning - but I suspect there is a drawback I'm not seeing.

- Ryan

 

[arnoldb]

Hi Ryan

Your solution will work for light facing operations, but there will still be backlash on the leadscrew, so the carriage will be able to still move a bit left to right.

The main reason for the carriage locking is to eliminate this backlash and make things more rigid for heavier parting and facing operations.

Don't worry too much about making modifications at first; just start off on a simple project and start using the lathe. You'll soon start to get a "feel" for it that will help you better judge which modifications to make first - as well as learning the basic machining skills needed.

Kind regards, Arnold

 

[Blogwitch]

Ryan,

There are a few ways you can lock up the saddle, and you can buy bolt on kits, but for the sake of one bolt, a brass slug for going into the hole first, if you have a tap and a hand drill, this is a fairly simple fix.

http://madmodder.net/index.php?topic=627.msg5085#msg5085

Sorry to send you to another site, I am just in the process of transferring a few of my old postings from there to here.

BTW, the whole post is concerned about straightening up a banana shaped old version of your lathe, and a tapered gib mod I did on it.


John

 

[Rayanth]

Bogs, I have read your post quite thoroughly, as I was sent to it earlier in this thread. My problem is the limitations I have due to lack of mill (and at present even drill press, and it will be quite some time before I can acquire one. My question was aimed mostly at a temporary workaround until I can do some of the more involved mods.

- Ryan

 

[Rayanth]

I picked up some .020" aluminum sheet for a chip guard on the gears as suggested earlier. For some reason it's painted Boeing Primer Green. Can't quite figure that out... I'm very familiar with the color, since I work there.

Anyhow, That will be the project for tomorrow - making the chip guard. It won't be drilled and screwed on. it will most likely just be super glued on in a few corners so it can be pried back off.

Today (and admittedly a little last weekend), I decided to chuck up some of the round brass I'd ordered, in the 3-jaw and give it a whirl. I have all the tools necessary to start making chips, but it's not entirely ideal just yet - nothing is bolted down, for example. And I still have no chip tray on the lathe, it's sitting on the cardboard I had it on for cleaning.

First was to grind up a lathe bit to one of the multitude of directions Steamer sent me in a private message, I chose I think the Sherline instructions and did my best to follow along. I'm rather pleased with the way the bit came out, but evidently the brass was not. Later found out brass likes less or no top rake. Was also cutting at I think too slow of a speed. The main idea was to see how much adjustment would have to be done to the bits to get on center. With .030" of feeler gauge 'shims' in place, I got very close.

Today I redid it all. Ground up a new bit, didn't touch the top face at all (that IS the top rake right? ... I need to look at those instructions again), took out the feeler gauge shims and faced the end again to see where it would end up. Once again, I had a nib of almost precisely .060" (just a hair over, immeasurable), so I added .030 feeler gauge, and came out really darned close... still a hint of a nip on the end, but evidently I'm too uneducated to figure out if that's good enough or how to deal with it.

I also turned down the side to get a feel for feed rate for a good finish there, taking it nice and slow. My lathe has no decent RPM readout on it, it merely has a non-segmented dial for speed, in lo it's 0-1150 rpm, in high it's 0-2500. I had it in high gear, about halfway up the dial or so, so in the 1250 range. Probably too fast? I was taking very light cuts.

Top Left and Bottom Left - the practice part. The turned portion is a little under a half inch long.
Top Right - the 'new' bit ground without the top face being touched.
Bottom Right - the 'old' bit ground pretty much as close as possible to the sherline instructions, the first bit I ground.

My results, to me, are admirable for a fresh start with no training. There is still some rifling to the cuts, but it's barely enough to feel as a faintly rough surface with a fingernail - is this about right, and I should just sand/file to get a better finish, or am I still needing work in my methods of grinding my bits ? (I did round the tip) Also for that little nib on the face - is that about what to expect, or do I still need to fine tune to get absolutely perfectly flat face?

- Ryan

 

[mklotz]

Keep working on the nib. Once it's gone, take the opportunity to make yourself a tool height gage...

Pick a good lathe reference surface (e.g., a flat way or the top of the cross slide or the top of the compound). Now with your new found turning skills machine a cylinder* (any metal will do) to a length such that when set on the reference surface, a thumbnail drawn across tool top to cylinder top will detect no step. Voila, a height gage - and a very sensitive one at that - fingers are incredibly good at detecting steps.

Mark its purpose on the side, not ends, of the cylinder and find a warm, cozy spot for it in your toolbox.

* If you're still getting pips while machining, drill the cylinder through so there will be no pips. Technically, the end of the gage that sits on the reference surface should be relieved so that it will sit dead flat. If you wish, you can do that easily by counterboring the base, either with the lathe or with a largish end mill. Leave at least a 1/8" wide annulus for the cylinder to sit on.

 

[Tin Falcon]

Learn to hone the tool. I have photos of how to somewhere around here.
Tin

 

[Rayanth]

Thanks for the suggestion, marv,

Tin, I will look into honing tools (whatever they might be called =) When I make a trip to the store later. Ran into some issues this morning.

Pulled out the tray for the lathe and cleaned it all up. Made the appropriate measurements off of the frame of my workbench so I could bolt through it rather than into it, then lined up the tray to transfer the hole pattern. Punched all four holes through with my newfangled DeWalt drill and a 5/16" bit, and then found out just how hard it is to line up a tray, rubber washers, and only half-visible holes on a 100 lb lathe all in line with the holes on the workbench. After a great deal of cussing and fiddling and nudging and probably a little more cussing (I lost track), I got the bolts started into the feet of the lathe, and stopped.

Should mention, Prior to this I had SWMBO's help in trying to shim up the workbench a bit to get it closer to level. Got it about as close as she was willing to give me the time for, and decided to level the rest on the lathe itself.

While resting from all the grunt work, I transferred the hole pattern for my bench grinder on the other end of the bench, where there's less light, but it's also well out of the way and won't get grinding dust into the lathe or electrical stuff. At this point I decided I wasn't entirely certain I had the best method in mind for handling the lathe, so I called up the father and had him come over to give it a gander.

With his help I got the bench much more level, this time with the lathe on it so it was so darned heavy I could only lift it a fraction of an inch for a brief second at a time. We then used some of his more precise levels to figure out how far off the lathe would be - and it's really not that far off. With the bolts still loose enough to lift the edges of the lathe to slide under anything to help shim it, we used a post-end bubble level (really nifty type of level, and dirt cheap but it's much easier to visualize what's going on in all dimensions) to find that we only needed to slip one little fender washer under one corner and it's about as level as it's going to get.

Then went to tighten the bolts and found that they're way too long. So I'll be making a trip up to the toy store today to get some shorter bolts - I believe I had obtained 75mm bolts, and 50mm would seem to be right about the right length if my measurements are correct - then I need also to get some longer bolts for the grinder, and some lag screws for the 4.5" vise.

After this, a "quick" tear down of the lathe so I can get the pattern for the gear cover traced over to the stock I have for it, and I'll be pretty much ready to run!

Just in time for my classes to start at the community college, and suck all my free time away

- Ryan