Lathe Carriage Lock

I haven’t done much with my lathe yet, since I’ve been busy with life and other projects (I finally finished the sprinkler system in my front yard – after 3 weekends of “it’s too hot to work outside”), but I have managed to find time to make a necessary improvement: a carriage lock.

The problem was that the manual gear-driven movement of the carriage when the auto-feed was not engaged was too free, so that when I cranked the cross-slide across the face of a workpiece, the carriage shifted left and right, making it difficult to create a perfectly flat surface.

I assumed I wasn’t the only person encountering this issue, and did a quick Google search to find out how others had addressed it.

Basically, the solution was to make a low-profile clamp that pulls the carriage down against the rails, much the same way the tailstock is held in place.

Since I was planning to copy the effect of the tailstock locking mechanism, I used the clamping piece from it as a template to create the parts.
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After milling out pieces for the top of the carriage and the bottom of the rails I drilled and tapped holes to allow a 5/16″ bolt to apply clamping pressure.
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I tested this out and found that it effectively locked the carriage, but it also tended to pivot too much underneath the rails and would jam up and prevent the carriage from moving even when the bolt was loosened.
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Luckily I had made the pieces out of thick enough metal to re-cut the bottom piece on the other side, this time with a much tighter fit between the rails so that it would have minimal ability to twist.
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This solved the problem. I can tighten down the bolt to lock the carriage and loosen the bolt while leaving the lock installed without worrying about the movement of the carriage being impacted.
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I may re-visit this design in the future, to see if there is a better way to design the clamp, but as it is I can fairly quickly lock and unlock the carriage using 1/2″ socket wrench.

One Belt To Rule Them All

The metal lathe I purchased used was in good condition, but there were a couple things that needed attention; one was cleanup, and the other was belts.

I focused first on cleanup. I took the various slides and screws apart, cleaned them off with mineral spirits, re-lubed, and re-assembled.

That was a nice task to take on, because it introduced me to the various parts of the lathe and gave me a better feel for its construction, capabilities, and limitations.

The next issue was that of the drive belts. My lathe came with one belt, but needs three in order to have full range of speeds.

The manual listed their sizes: 0-710, 0-800, and 0-900. Great! So I did a search online for belts of this size, and found… links to the manual for my lathe!

That’s right: Harbor Freight had managed to use belts on this lathe that no longer exist in reality.

Just in case this was a fluke, and the internet was defective, I went to the local auto-parts store and showed them the sizes to see if they could find something similar, and they could not.

I called Harbor Freight technical support, and spent a long time waiting while they verbally scratched their heads, and then they came up with the answer: 710, 800, and 900 were the size of the belts in millimeters! (that may have been obvious to you metric readers, but I live in America, the God-Blessed land where measurements are based on thumbs, grains of wheat, and historical monarchs’ feet (hey, you started it, England))

So I converted millimeters to inches and ordered three v-belts from my favorite supplier (locally based so  they ship very quickly), and tried to put them on my lathe.

Not one of them fit.

I could almost get the smallest one on, but it was so tight I nearly lost fingers in the process. All three pulleys are in fixed positions, so I couldn’t shift them to loosen or tighten the belts.

Oh well, I thought, at least I know what sizes to order next, so I bought two more larger belts (I decided that I would only buy two, and continue using the old belt as well).

Failure!  These belts were also too small!

I had now accumulated $30 worth of belts without successfully equipping my lathe.

Metal Lathe Belts - Failures

After this, I took a different approach. V-link belts are a favorite for woodworking equipment because they don’t have as much memory as a standard solid rubber belt, and so lead to less vibration and smoother cuts.

I have one of these belts on my table saw, and while I haven’t seen an appreciable improvement in the quality of my cuts, I like the belt because I can adjust its length fairly easily.

These belts tend to be expensive. $7-9 per foot, or $30-40 for a 5-foot loop.

I found mine at Harbor Freight. It’s a name-brand product, so it’s still not cheap, but $25 for a 5-foot loop and then a 20%-off coupon means it’s $20 and a lot cheaper than anywhere else, and I could use the 5-feet plus a few extra links from my table saw to make both the belts I needed.

Metal Lathe Belts - Solution
After picking up a belt on my lunch break, I spent 10 minutes tweaking the length of the belts and getting them fitted.

They fit. The pulleys turn. The Lathe cuts. Done.

Metal Lathe Belts - Installed

Why don’t I always try the obvious solution first?

Pardon the Repetition

I have said this before, but I feel the need to make excuses for myself once again.

It has been a while since my last post, and unfortunately it was something of a cliffhanger.  I am moving at full speed towards setting up a little “machine shop” with a milling machine and a metal lathe so that I can really start to explore the metalworking world.

Oh, did I mention I bought a lathe? I had intended to purchase a new Taig lathe, with all the trimmings (power feed, headstock and tailstock risers, tooling, etc), but I happened across a larger 8.5″ x 18″ Chinese lathe from Harbor Freight on Craigslist and (somewhat impulsively) bought it instead.

Time will tell if that was a good decision, but at least, since I bought it used, I have the opportunity to turn around and re-sell it for a similar price if I find it to be lacking.

So, back to my original purpose for this post: making excuses for myself. I have continued to be very busy with my job and working on my house. My hope had been that things would calm down after mid July, but they have not.

And so updates will likely be scarce for the time being.

When I do find time to tinker in the garage, I’ll try to remember to take some pictures and tell you about it.