Copyright 2000-2002 by Frank J. Hoose, Jr. Home
Homier 7x12 Mini-Lathe Review
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Copyright 2000-2002 by Frank J. Hoose, Jr. Home
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The author is not a professional machinist or engineer; no information provided herein represents professional advice or best practices. All information is provided to help hobbyists and other non-professionals gain a better understanding of the tools and techniques described.
Considerable care has been exercised to provide accurate and timely information. However the author cannot be responsible for information which is incorrect or out of date.
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All practices, procedures, modifications and product recommendations described herein are to be used at the discretion and risk of the reader.
Bed and Ways
The bed is sturdy cast iron with the usual rough finish on the less visible surfaces.
One thing that impressed me right off was the quality of the ways. They have a very fine finished appearance with crisp, ground surfaces.
There has been a fair amount of discussion in the 7x10 group about whether the ways on the Homier (and for that matter, on the other 7x lathes) are hardened. On expensive high-end lathes, the ways essentially are always hardened. This is desirable, since it helps to protect them from dings and gouges which can affect accuracy or cause binding of the carriage as it travels down the ways.
On the end of the bed of the Homier lathe is a little label that reads "Heat Treatment". This label has led to speculation that the ways are hardened. However, some have interpreted this to mean merely that after casting the ways are heat-annealed to relieve stress in the casting before grinding the ways.
Now, "hardness" is hard to measure without special instruments. For our purposes, the real question is this: "If I drop a wrench on the ways, will it leave a big dent?". So I set out -- rather unscientifically I might add -- to answer this question. Here's the result: If you whack the top of the compound with a wrench it leaves a dent. Do the same on the ways and the dent is much smaller - just a mark, really. I repeated this precision test on the other lathes and got pretty much the same result. So I think that the answer is that the ways are harder than the raw metal of the compound, but not nearly as hard as, say, the chuck jaws. I could not conclude that the ways on the Homier lathe are any harder or softer than those on the other lathes. Now if one you readers out there could lend me a hardness tester...
Gear Train and Levers
Looking at the left side of the lathe you will see the cover for the gear train. Removing the two bolts at the top of the cover releases it and reveals the gear train. The arrangement is essentially the same as on TOL.
On the back side of the headstock are located the Hi/Lo range selector lever and the leadscrew drive lever. The Hi/Lo range lever shifts gears inside the headstock to change the upper RPM limit from around 1200 in low range to about 2500 in high range. Hi range is typically used for polishing rather than cutting operations.
The leadscrew lever is shifted by pulling back on the knurled sleeve and then moving the lever up or down into one of three detents:
Leadscrew
As on the TOL, the leadscrew is 16 TPI. The right end is terminated by a special nut. At first I thought this might be used to take up any play in the leadscrew, but it seems to lock down leaving a fixed clearance between the face of the nut and the pillow block, so I'm not sure what purpose it serves.
Update 4/14/02
Gregg Eshelman pointed out to me that there is a setscrew in the nut which engages
with the end of the leadscrew. Adusting the setscrew thus adjusts the clearance
between the face of the nut and the side of the pillow block, so the nut can, indeed, take
up any slop in the leadscrew.
End of update
Removing the nut exposes a threaded extension that might lend itself well to use with an optional hand crank or power feed.
When I removed the pillow block, I discovered that there is a ball-bearing oil port on the underside. Gravity being as it is, I decided that it made more sense for the oil port to be on the top side of the block, so I flipped it over when I reinstalled it.
Half Nut and Thread Dial
The half nut clamps around the lead screw to drive the carriage under power. I was impressed by the crisp engagment of the half nut lever. On both of my other mini lathes the half nut has a somewhat mushy feel. Looking at the threads on the half nut, it appears that they are cut more cleanly on this lathe, and that may account for the difference in feel.
The thread dial has a light finish rather than the black color found on TOL but is otherwise similar. It is used to engage the lead screw at the proper point when thread cutting.
Carriage and Saddle
The carriage rides along the ways and supports the cross-slide and compound. The saddle is the horizontal piece that rides on the ways and the apron is the vertical piece on which the carriage handwheel, drive gears, half-nut lever and half-nut are mounted. The handwheel is made from plastic but not the Bakelite type used on TOL.
The carriage can be moved rapidly by hand using the carriage handwheel, which engages with a rack along the underside of the ways. Movement was pretty smooth, with no apparent binding. The carriage can also be moved under power feed to obtain a smooth, even finish on a turning operation, or when cutting threads. When the leadscrew is being driven by the gear train, twisting the half nut lever to the DOWN position engages the leadscrew; UP disengages.
Removing the carriage and inverting it reveals the drive gears and the half-nut. The saddle is retained on the ways be two metal strips with adjusting screws to set the clearance - the same arrangment used on TOL.
Way Wipers
A nice feature of this lathe not found on the others is wipers for the ways. These are attached to both sides of the saddle and serve to prevent swarf and chips from working into the gap between the saddle and ways.
Removing one of the wipers reveals that it consists of a soft rubber wiper held in place by a thin metal cover. Also unique are the ball-bearing sealed oil holes above the wipers on the right side.
Cross Slide
The cross-slide is similar in construction to TOL but I would rate the machining as better quality.
The cross feed nut is cast iron rather than brass, but the backlash adjustment is the same. The finish on the gib bearing surface was definitely better than I am used to seeing.
Compound
Mounted on the cross-slide, the compound can rotate and be locked at an angle for cutting short tapers or threads. As on TOL, the locking screws are underneath the compound slide, so you must crank the slide nearly all the way back to gain access to the locking screws.
The dovetails were nicely finished, but I found quite a lot of swarf and grit in the grooves, so be sure to clean this area thoroughly with a brush and some kerosene. Then apply a liberal amount of light oil or white lithium grease to lubricate the slide.
I also discovered a small manufacturing defect: one of the bolt holes in the compound swivel plate was not threaded properly (the hole on the left in the photo above) and the locking screw could not be tightened down. I first tried tapping the hole to 6x1mm, the original thread size, but the bolt still did not get a bite on the threads, so I tapped it out to 1/4-20 and replaced the bolt. That did the trick.
Interestingly, while the dial on the cross-slide had no grease on it at all, the compound dial had a thick coating of grease. The protractor is made of plastic and I found it a little hard to read compared to the cast metal ones on TOL.
Dials and Handles
The cross-feed and compound dials are provided with setscrews to lock them at at a specific setting rather than the friction spring arrangement found on TOL. For convenience, I will probably replace the setscrews with little thumb screws so that I don't have to search for the proper hex key when I want to lock them down.
This is a better setup than the friction locking arrangement, since the friction locking ones are subject to slipping. When they slip, it can be really frustrating - especially when you are cutting threads to a specified depth and have no way to reestablish the reference point once you start cutting. For this reason, in fact, I added this feature to my 7x12 as shown below.
The chrome handles have a slightly different shape than those on TOL. I'm holding a handle from the HF 7x10 in my hand next to the Homier handle.
Be sure to remove the handles and dials and clean the dials, as I found a lot of grit on the back face of the dial. You may need to insert the tip of a screwdriver and twist it to gently pry off the handles.
3-Inch 3-Jaw Chuck
The chuck appears to be identical to those on the HF and Griz lathes, judging from the planet logo and other markings. From my experience with those lathes, I can attest that this is a fine chuck and should do just about anything you would expect from a little chuck on an inexpensive lathe. It is not unusual for the moving parts to be somewhat stiff until it gets worn in, and this chuck was no exception.
The bottom left hand photo above should give you a good idea of the true size of the chuck. Its small, but you can supplement it with a variety of optional chucks if you need more capacity.
In the bottom right hand photo you can see that lock washers are supplied for the chuck mounting nuts. None are provided on the other 7x lathes, nor needed within my experience. They're probably a good idea, though, if you don't mind fooling with the extra hassle of getting them in place. Captive washers would be nice.
The mounting nuts provided on this lathe are somewhat thinner than those on the other lathes and this makes them a little easier to get into position on the studs within the narrow space between the back of the chuck and the headstock.
Tailstock
Features of the tailstock that differ from TOL are as follows:
I was a little surprised that there were no graduations on the ram to indicate drilling depth. This is not much of a loss, in fact, since they are difficult to read anyway on TOL. In practice I use my little depth gage for approximate depths and a dial indicator for precise work.
I found the tailstock alignment to be quite good, right out of the box. I mounted the dead center in the tailstock and a piece of 3/8" drill rod turned to a point in the chuck and brought them together. As you can see in the photo, they meet up point-to-point.
If you look carefully you can see the stop screw in the groove in the bed just below. I assume that this is to prevent you from accidentally sliding the tailstock off the end of the bed. I routinely remove mine when its not in use to gain the extra room, so I will be removing this little guy first thing.
Toolpost
The toolpost has a plain metal finish rather than black oxide. Though essentially the same dimensions as on TOL, the toolpost is mounted about 0.10" lower and is therefore better suited to 3/8" tool bits instead of the 5/16" bits used on TOL. I found that even a 3/8" bit was below the centerline and had to be shimmed. The underside of the tool holder has notches that engage with a spring-loaded detent to lock the holder at one of four positions. TOL have this feature, but I have routinely removed the spring and pin so that I can easily set the holder to any angle I want.
A drop of Loctite on the threads of the handle will prevent it from twisting loose in use. I use Loctite on all the handle threads throughout the lathe.
Mini-Lathe Mini-Mill Bandsaw Grinder Anodizing Lapping Links Safety Premium Content
Mini-lathe: Accessories Adjustments Capabilities Chucks Dial Indicators Features
Getting Started Glossary
Introduction Materials Modifications My Shop Operation
Reviews Sieg
Factory Tool Grinding
Troubleshooting Tuning Versions