Grizzly G4003 Lathe-modifications to RideTheGearTrain (free online to calculate the change gears needed to cut a thread. I had quite a busy time in the days leading up to Christmas. I had contacts from a couple of people who needed their lathe gearboxes added to the program (RideTheGearTrain). One lathe had crazy features I had not heard of before. It was a Chinese-made Grizzly G4003 (2005) model sold by the American Grizzly company. The spindle shaft is 16mm and the leadscrew shaft is 19mm, so they have two sets of change gears. This meant that I had to modify the program to handle it. It would have been a huge job to re-write the whole program, but not long ago I added a filter system. The user enters ALL their change gears initially, but they also click the button, currently labeled "Exclude Large gears", and here the user can enter a separate list of gears permitted for each position (or stud) in the gear train. If the program produces results with gears that are NOT permitted in any position, those results are deleted (filtered out) and only the reduced list of results is displayed. I added this filtering system a few months ago to prevent the display of results where a gear is too large to fit on the machine. A user had this problem. So the user enters a size limit (by number of teeth) for any position they want restricted. For example on some lathes there is a casting near the stud gear that prevents large gears from being fitted. If the size limit for the stud gear is 60 teeth, then the user enters 60 as the maximum size for the stud gear. Results using larger gears are filtered out. An advancement on this idea was to actually measure the distance between studs on the banjo, and from the DP (Diametral Pitch of the gears) the size of gears can be calculated. When there are gears on two 'studs' (or shafts) on the banjo, the radius of each gear is proportional to the number of teeth on that gear. The space required is the sum of the two radii. We can use the sum of the teeth on the two gears and from that calculate whether the two gears will fit between the two studs. If they don't fit, the filter program will remove the results from the list of results to be displayed. This method is rather complicated and I doubt whether anyone uses it. I haven't had any feedback about it. I did not have my Boxford in Tennessee when I wrote this. Now I am in New Zealand I could measure my lathe and see if it works. It probably isn't foolproof because fitting one pair of large gears on the banjo will limit how much room is available for the next pair. We could add up the teeth of ALL the gears on the gear train, but that would only work if the gears are arranged in s straight line, which they are not. Some more thought may be required. Going back to the weird Grizzly lathe, it has another quirk. It is fitted with a 91/86 compound pair for imperial to metric conversion. It is designed in such a way that this gear cannot be flipped over. RideTheGearTrain automatically tries flipping over compound pairs and it is quite surprising to me that it produces nearly as many results with the conversion gear flipped. A conversion gear with a ratio approximating 1.27 is fairly close to 1.25 which happens to be quite handy! So, how can we prevent RideTheGearTrain from displaying results with this gear flipped? Easy. Just use the filter system to tell the program to filter out any results where the gear in position Compound 2 (comp2) is larger than 87. Now with this filter system we can accommodate this peculiar lathe. Now I understand better why it is done this way. The gears designed to go on the leadscrew shaft have a long extended boss on one side - like a built-in spacer. If you put it with the spaced to the right, the gear engages with the metric conversion gear. If you flip the leadscrew gear over, so that the spacer is on the left, it now meshes with the gear on the compound pair which acts as an idler. This is used for cutting imperial threads. These leadscrew gears with the extensions cannot be used as stud gears. So, this lathe comes w

I can not work without many "Digital Electronic Vernier Caliper" in my workshop. However, they are always hiding them self when I am doing my job. Lately I have discovered that they are missing the numbers on the display. Both old and new ones. Suddenly the numbers are being negative or shutting down. I am blaming a Comunicacion tower not far from the building. Someone's that has a good advice for me? Best from Johannes

Some time back I started working on a DRO scheme for my lathe cross slide. There's not a lot of room on top so many of the approaches I saw had one disadvantage or another. As a result I came up with a scheme to put the DRO underneath the lathe and used a "C" shaped piece to transfer the cross slide motion beneath the lathe. I had an iGaging DRO for the purpose because I bought two when I was working on my Z axis DRO setup, so I already had what I needed. Or so I thought. Unfortunately, the iGaging design uses a sliding contact with a fairly strong spring, which required a fair amount of force to overcome. DRO mounting schemes that put the mounting system inline with the sensor aren't affected by this, but my C shaped piece would deflect under the force enough to cause about a .005" error. I tried several ways to stiffen up the system but that was about the best I could manage. So I decided to modify my DRO to reduce the amount of force needed to move the rule through the sensor. This involved making a replacement base out of aluminum and replacing the sliding contact with bearings. I used aluminum because the rule MUST be connected to the sensor's internal ground in order to work correctly. My first iteration used flanged bearings because the rule needed to be constrained on two of its axes, but the flanges rubbed on the rule too much, which caused erratic variations in the force needed to slide the rule back and forth. So I replaced the flanged bearings with conventional ones -- but then had to add bearings to the bottom and top assemblies to constrain the rule on its vertical axis. At this point I debated on whether it really was worthwhile to continue my attempt to use an iGaging DRO, but since I already had a fair amount of time invested in this thing I forged on. This is known as the "sunk cost" syndrome, and I admit to falling victim to it. So after buying more bearings and spending more machining time on the base (and 3D printing a cover, also with bearing pockets) I got this: The top photo shows the scale, sensor, aluminum base and printed cover. The side bearings are 3x10mm and the top/bottom are 3x6. And here are photos of the mounting scheme: I used a "T" extrusion in an attempt to stiffen up my "C" assembly but it didn't improve things much. The 3D printed stuff was done with an older Ender 3 I bought from a friend. This is the first project I've used it for. The pieces were designed using openSCAD. Not shown: all the pieces that had something wrong with them :). The scale passes through a slot I milled in the vertical piece. At first the (re) assembled DRO had a terrible EMI problem. I added some shielding on the back of the sensor board, which helped a teensy bit. It turns out that the main problem was the spacing between the bottom of the sensor board and scale. I had used some 3mm brass washers to make sure the board didn't rub against the scale, but that turned out to be a mistake. I removed them and suddenly the noise problem disappeared. The board still isn't rubbing so that was a solution without a problem. I was sure that the DRO would misbehave once it was installed and the motor controller was turned on, but so far so good. I checked the DRO vs the dial and they are very close. That was a big unknown, since I wasn't sure if the spacing between the scale and sensor board would affect the readings. Lipstick on a pig? Well, probably. If I had known what I was going to encounter along the way I think I would have just bit the bullet and found myself a DRO that would work right out of the box....

My 7x12 Northern Mini-lathe has suddenly quit working. Previously, when I flipped the switch from forward to reverse I heard relays click. Now nothing. The fuse tested good. I did not see any evidence of burnt parts. I know something about electronics, but it is hard to proceed without a wiring diagram. I do not have an oscilloscope, but I have a VOM. I would hate to replace the control board, only to find that the problem is elsewhere...... I looked online, but did not find anything relevant. Richard

I've got a 70's era radial arm saw with a dust collection port that doesn't match current vacuum fittings. I bored one end of a 1 1/4" PVC coupling to fit the saw outlet and the other end to fit the vacuum hose. It works, but for long term a 90-degree fitting would be much better. I have a 1 1/4" PVC 90 that I would like to bore out to do the job. However, having trouble figuring out how to mount on my 3" 4-jaw chuck (see photo). I need to mount so the opening(s) is centered on the spindle so the 4-jaw adjustment capability would be great if I could get it mounted. Any ideas on how to mount?

When I purchased my mini lathe (about 5yrs ago) it was advertised as having a 16tpi lead screw. I recently decided to check and noticed that is not the case. It is actually the 1.5mm pitch leadscrew instead. I am considering purchasing a 16tpi replacement along with new half nuts. I found the items on Arc Eurotrade. However, the shipping to the US is a bit expensive. I haven't been able to find these items on Amazon. eBay and AliExpress have the metric version but I cannot find imperial versions. Little Machine Shop has lead screws for Sieg 7x14 lathes, but I believe there are some differences that may cause problems. Has anyone else made this swap or have suggestions as to where I should look for these items. Thanks in advance.

A few times I have mentioned how the back splash on mini lathes doesn't really scale down well from larger lathes and makes things too crowded when trying to work around or clean the back side area of the lathe. "Mr. Pete" (Tubalcain) has been running a series on the early Unimats, and out of the blue somebody sent him a little cabinet with a backsplash that was ANGLED. This seems to help greatly in opening up the space behind the lathe. The notches are designed to hold tool holders, but you could make notches, or holes, for anything to get additional utility. Or none at all. You could make a top bend rearward and horizontal and put holes in it to hold centers and such. The part here is stainless and must be pretty thick as he said it weight 10 lbs. Here is the entire YouTube video where he shows this. https://www.youtube.com/watch?v=SZa2m90p0dA&t=504s This is one of those things where my reaction is, "Why didn't I think of that?" Charles E. "Chuck" Kinzer

I have a 6" x 1" round piece of aluminum that I need to turn into a flywheel for the model engine I am building. I was thinking of using superglue to secure it to my faceplate as it obviously does not fit in any of my chucks. Any suggestions how to hold this or should I go looking for someone with a bigger lathe. Dave Borneo