Taught my machine a new trick today...

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Torch
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Taught my machine a new trick today...

Post by Torch » Wed Apr 17, 2013 2:13 pm

One of the things that has always bugged me about this machine is the cross-slide table lock arrangement. Typical of this design, there's two separate thumb screws, each of which must be individually tightened to lock the table. And sometimes it's very difficult to get your fingers in there, especially when using the tailstock. Well, that used to be the case:
cross-slide_locks.jpg
I couldn't find a heim joint with provision for two rods, so I made my own by pressing out the cup and ball from a regular rod-end heim joint and pressing it into my shop-made housing. For the locks themselves, I replaced the stock thumbscrews with 8mm Allen head cap screws and bored the arms for a light press-fit. With the locks set, I tapped the arms in place, unscrewed the assembly and welded the backside. The control arm is hanging on a 10mm pivot that is threaded into the new 8mm hole I drilled and tapped in the table. Everything is below the table top level at all points of travel.

With the locks released, the back of my hand does bump the lever when cranking the carriage left or right IF the table is near it's innermost point of travel (as shown in the picture). But that is only because of the oversized handwheel I made for the carriage, and I can simply lift the handle to the locked position. A small price to pay!

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ctwo
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Re: Taught my machine a new trick today...

Post by ctwo » Wed Apr 17, 2013 4:48 pm

Forgive the deviation, but that looks like a dial on your carriage wheel - and I like your lead screw cover... Which lathe is that?

And I've yet to teach my lathe anything. Usually I'm student (or pupil)...Your mod looks functional. I'm stuck with tightening 4 small flat blade screws for the gib to lock my cross slide.
Standards are so important that everyone must have their own...
To measure is to know - Lord Kelvin
Disclaimer: I'm just a guy with a few machines...

Torch
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Joined: Wed Mar 17, 2010 7:58 am
Location: Muskoka

Re: Taught my machine a new trick today...

Post by Torch » Wed Apr 17, 2013 7:23 pm

The machine is an HQ800V, made by Chinzou Household Machine Tool company of China -- they are the factory that makes many of the housebrand 3-in-1 machines sold by Grizzly, Busy Bee, Harbor Freight, etc. I ordered it with the certain features and options that I wanted but weren't available in the housebranded versions -- or at least, not all available in one housebranded model. But essentially, they are all based on the same core castings and design so I thought this mod might be of interest to anyone with a similar machine.

I'm not sure which dial you are referring to -- there's a dial around the shaft of each handwheel, although to be honest I virtually never use them. The carriage dial in particular is too small, too far away, and hidden beneath the table much of the time. I have a 3-axis DRO mounted in a much more visible location.

There is also a threading dial at the lead screw. That was an early modification -- the lead screw cover as designed was mutually exclusive with the threading dial mount, so I came up with my own to accommodate both -- who says you can't have your cake and eat it too? <lol> The cover has worked out really well. It's basically a pair of spring steel coils (one for either side of the carriage). It does reduce the travel by an inch at either end, but that hasn't been an issue thus far (I could remove it temporarily if I had to).

Other mods in the picture are the felt bed wipers, the redesigned compound base and of course the enlarged handwheel for the carriage. I find that last one makes it much easier to be precise, as the stock gearing is too coarse for my skill level.

My attitude is "if something doesn't work well, make it better". I've done a few other things not visible in the picture, most of which have been photographed and posted in this forum. I modified the change gear set to facilitate and simplify the process -- I still have to swap a couple of gears to switch from feeding to metric threads to inch threads, but it's a much easier process now and I call that my "fast gear change" setup. ;-) I fabricated aluminium replacements for the nylon-clad headstock gears. Replaced the lead screw roll pin with a brass shear pin and similarly replaced all the steel gear keys with copper ones to protect the expensive bits in case of a crash.

I added an oil fill plug to the front of the headstock gearcase because the one at the rear was all but inaccessible (installing a valve and hose in place of the drain plug is on my "to do" list). I swapped out the carriage gib screws for longer ones with locknuts that I can readily adjust rather than the recessed ones that were next to impossible to lock in place properly. I replaced the original SCR variable speed controller with a pair of PWM controllers with separate controls for each motor. The PWM controller runs the (DC) motors quieter, smoother and with more torque at low speeds and the dual controls allow me to use the lathe motor as a power feed when milling. I've also done a lot of tweaking, things like tramming the mill head, fine-tuning the QCGB alignment, dressing the key slots in both the lead and crossfeed screws to reduce wear on the half-nuts they mate to. Etc.

I've had a lot of fun with this machine, both learning about machining in general and using those skills to make things. And part of that fun has been customizing the machine itself to better suit my needs. So if there's something you find awkward about your machine, my advice is CHANGE IT! :lol:

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ctwo
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Re: Taught my machine a new trick today...

Post by ctwo » Fri Apr 19, 2013 1:15 pm

It was the dial that moves the carriage along Z. I recently asked in another thread why I never see a dial there, and there I now see one on your machine.

I have been considering making a dial for my carriage wheel, but many in that other thread mention how inconsistent it would be, being driven by a sloppy rack and pinion that could easily pick up a chip and be off, and likely resulting is some odd linear distance traveled per revolution too...

I am so spoiled by the DRO on my mill that I'd love one on my lathe, even just on z-axis as that is the only movement that has no indication at all. I'm perplexed that most lathes are manufactured this way.

A one or two inch dial indicator is so hard to mount on my lathe because all the surfaces are rounded in two axis, so mag mounts don't stick reliably. I'll have to figure something out because it's getting tiring.
Standards are so important that everyone must have their own...
To measure is to know - Lord Kelvin
Disclaimer: I'm just a guy with a few machines...

Torch
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Joined: Wed Mar 17, 2010 7:58 am
Location: Muskoka

Re: Taught my machine a new trick today...

Post by Torch » Fri Apr 19, 2013 3:33 pm

I can't imagine doing without some sort of indicator on the carriage travel. So many operations depend upon accurate positioning. I've even been known to use that axis to measure things that are too long for my traditional metrology but can be mounted on the lathe.

Can you make a "saddle" for your rounded surfaces to provide a suitable mounting surface for DRO scales, mag base, etc.?

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ctwo
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Re: Taught my machine a new trick today...

Post by ctwo » Fri Apr 19, 2013 6:39 pm

DRO is out of the budget. So far I've gotten away with a typical mag base dial indicator on the chip pan, but that has a long mount and gets in the way for close to the chuck work.

I was thinking of making a bracket to mount a horizontal rod where the quick change gearbox bolts on, and then mounting the dial to that rod the usual way. That would give me a quick movement to set up or slide the dial out of the way. Either that or mount the dial back there and use extensions on the dial rod or off the carriage. I have not thought up a good way yet.
Standards are so important that everyone must have their own...
To measure is to know - Lord Kelvin
Disclaimer: I'm just a guy with a few machines...

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ken572
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Re: Taught my machine a new trick today...

Post by ken572 » Fri Apr 19, 2013 7:53 pm

Torch,

VERY COOL! Modification. :wink: 8)

I will have to do that on mine..

Ken. :)
One must remember.
The best learning experiences come
from working with the older Masters.
Ken.

Torch
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Joined: Wed Mar 17, 2010 7:58 am
Location: Muskoka

Re: Taught my machine a new trick today...

Post by Torch » Fri Apr 19, 2013 8:12 pm

ctwo wrote:DRO is out of the budget.
Maybe keep your eyes open for a used Trav-a-dial?


Ken,-

Thought you'd like it. :wink:

EDIT: Ken, I'd also highly recommend the felt wiper mod. Keeps the chips out from underneath and helps keep a thin layer of way-oil evenly distributed at all times.

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ken572
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Re: Taught my machine a new trick today...

Post by ken572 » Sat Apr 20, 2013 4:07 am

Torch wrote:Ken,-

Thought you'd like it. :wink:
EDIT: Ken, I'd also highly recommend the felt wiper mod.
Keeps the chips out from underneath and helps keep a thin
layer of way-oil evenly distributed at all times.

Torch,
Thanks, I must have missed that post. :roll: I will check it out.. :wink:

Ken. :)
One must remember.
The best learning experiences come
from working with the older Masters.
Ken.

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