Lathe: Crank Retaining Bolts

The stock retaining bolts for the cross slide and compound cranks are socket head cap screws. I was constantly hitting my knuckles on them and was annoyed by them whenever I used my lathe.

I realized that some Avid Single Digit v-brakes for bicycles come with retaining bolts with the socket head sunk into the body of the screw itself:

 They sit the lathe's cranks perfectly. The only issue is you need to put a pair of washers between the crank and dial to space it correctly. The new bolts almost sit flush with the cranks and I have yet to hit my knuckles on them again. The bolts should be available in most bike shops.

Lathe: Cross Slide DRO

Please read the complete article:
http://benchtopmachineshop.blogspot.com/2017/04/lathe-touchdro_12.html


I've wanted a DRO on my lathe's cross slide for a while to deal with the back lash and confusing dial markings. I bought s digital caliper to adapt to the role, like I've seen several people do before. However, I want to make sure I still had rotation of the compound slide. I ended up mounting next to the side of the cross slide, with the caliper's readout mounted stationary to the carriage via a bolt through the base of the display.

I wish I could give directions on how to do it, but individual calipers are built differently, so there's a very good chance what worked for me won't work for you. You just need to buy a caliper and fool with it until it works.

Even though this is an annoying modification, I'd highly recommend it just for the added usability.

Mill: Gibs

Please read the complete article:
http://benchtopmachineshop.blogspot.com/2017/04/mill-gibs.html


I think the gibs which come with the mill are fine, except the divots for the set screws are woefully inadequate. Because the set screws aren't pushing against a flat, they tend to rotate the gib, which compromises rigidity and creates uneven wear.

To fix this I decided to machine proper flats into the gibs for the set screws to sit on. First I removed all the set screws for the gib, then installed and positioned the gib. I sharpened the end of two M4 set screws in my lathe and first installed one and tightened it down, and then tightened the other one in each hole in turn. This left exact center marks for all the set screws. From measurements it looks like the gib angle is 55*, so I used my Wixey angle gauge to set my angle vise. Since the gib wanted to rotate when the vise was tightened, I placed a section of 1/2" steel rod in the corner formed by the gib and vise jaw, and then used my table clamp set to push down on the rod, effectively locking the gib in place. I then machined the flats using a 3/16" end mill with a plunge cut. For the lock's flat I used a 1/4" end mill.  By the way, that gouge you see is what happens when your vise decides to let go of the work.

The set screws were also upgraded from the stock dog point to cup point. The last couple millimeters of the set screws were turned down so they just fit in the gib pocket. This helped position the gib horizontally and keep it from sliding on the set screws.

I also took the opportunity to lap the gib slightly, but it turned out it was pretty flat to begin with. Once everything was reassembled, the gib has much more contact with the dovetail, and I can tighten the set screws tighter without making it hard to move. It was well worth it in my opinion.

I didn't like how the gib locks looked either. They have a rounded nose which pretty quickly becomes deformed through use. 

I figured if they had a flat nose to push against a flat surface, they'd work a lot better and wouldn't deform. So it was disassembled and thrown in the lathe where its end was extended and faced flat. Since its end turns on the gib I greased it just before assembly.

Mill: MT3 Spindle Release

The X2 comes with either a R-8 or MT3 spindle taper, with my mill having the MT3. Aside from there being more tooling available for R-8 it's biggest advantage that it's self releasing. To release an MT3 which has been over tightened will require much beating with a hammer on the drawbar. Even release a lightly tightened MT3 means at least one hit with a hammer. Personally, I don't like hitting my mill with a hammer.

However, even though I could change the spindle to R-8 for $60, I like that MT3 offers me more Z axis clearance. I also don't particularly want to spend $60. To allow me to eject the tool without having to use a hammer, I bought an 8" C clamp for $14 and cut the end off to give it enough clearance when there's a tool in the spindle. To eject the tool I simply loosen the drawbar, put the clamp in place with the base on the bottom of the spindle and the top of it on the drawbar, and then tighten it until it pushes the tool out of the spindle.

UPDATE: I modified the bottom of the clamp to better support the bottom of the spindle.

Mill: Gas Spring Installation

After going back on forth on whether the gas spring was worth it or not, I decided to go ahead and do it. The added Z axis travel would be nice, and getting rid of the inconsistent torsion spring would make mounting the Z axis DRO much easier.

One thing I didn't like about the install was it wanted me to drill a half inch hole in the back of the column. I'm not a huge fan of putting holes in my column. Instead, I grabbed a piece of 1.5" UHMW tube left over from another project, cut it down to 5 inches long, and then squeezed it into an oval cross section using my bench vise and heat gun. I then drilled a 8mm hole through it 4.5" from the end. One end of the gas spring is bolted through using the hole, and it's then lowered down onto the column. The UHMW tube then site on the mill's base inside the column and spaces the gas spring correctly. This way there's one less hole in my column.

On a related note, UHMW is a horrible plastic to machine. Use something else unless it's absolutely necessary.

Ultimately, I think for the money this upgrade is worth it. It's not a huge difference, but it makes the mill nicer to use and definitely made mounting the Z axis DRO much easier. It also doesn't stick up above the mill as high as I thought it would. From the picture you can see it only sits a couple inches above the motor.  

Lathe: Favorite Tool Bit

I love this tool bit set up:

It's two carbide tipped tool bits I bought from Amazon (only $3 each) and mounted back to back in a tool holder. This allows me to switch from turning to facing extremely quickly and easily. The turning bit will get a lot more use, so when it starts to dull I'll just switch the two.

Mill: Z-Axis DRO

Please read the complete article:
http://benchtopmachineshop.blogspot.com/2017/04/mill-touchdro.html


Once I installed the gas spring and removed the old torsion spring, installing the Z axis DRO was super easy. I removed the ruler on the left side of the column a while ago, since it was so course it was pretty much useless. The 12" iGaging digital scale was the perfect length to screw right into the holes left by the ruler. I then quickly fabricated a bracket to connect the scale's reader to the threaded hole on the head which used to hold the ruler's indicator. Perfect.

With the addition of the this last digital scale I now have one installed on all three axes. Further down the road I really want to eventually convert the scales from using their individual displays to using an Android tablet as a DRO with this:
http://www.yuriystoys.com/search/label/DIY%20DRO%20Project