[BlackICE1]

Have you tried to mill any steel after the mods? It should work much better now.

[ShopRat42]

Have you tried to mill any steel after the mods? It should work much better now.

The only thing I've done with the mill since is surface the bottom of the tool post holder. Which I knew going in wasn't going to be fun, I think it's some kind of cast steel. I don't really have much experience milling so everything I do is a learning experience. I used a 9/16" two flute end mill to take 0.040" off. I ended up with a decent result. I did get some chatter at the ends but honestly my two issues were work holding rigidity and that cast seemed like it had a lot of sand in it which dulled the end mill in short order.

[BlackICE1]

How easy was this to do? I think that part is cast iron which is hard to weld to, especially with my low end HF MIG 151.


I also wanted to support the little cast rectangular piece that connects the main head casting to the rear plate. Being only connected with one bolt seemed like would invite movement. So I put this little gusset piece in.

[ShopRat42]

It actually welded very nice. I'm welding with a Hobart 180 25%CO2 gas. No preheat or cool down on the weld. I was going to drill and bolt it on, would be a lot smarter but honestly it came down to I hate drilling so I gave it a shot. I think the material might actually be cast steel the way it welded. The main machine frame however I think is cast iron. Which you could weld to but would need to preheat, slow cool down and used a cast type electrode on an arc welder.

How easy was this to do? I think that part is cast iron which is hard to weld to, especially with my low end HF MIG 151.

[ShopRat42]

My next modification will be to copy someone else's fix and make some jib screw buttons on the quill. I believe they had used brass but I have a bunch of UHMW laying around I'd like to try, it acts a lot like teflon i.e. self lubricating and tough.

[BlackICE1]

My next modification will be to copy someone else's fix and make some jib screw buttons on the quill. I believe they had used brass but I have a bunch of UHMW laying around I'd like to try, it acts a lot like teflon i.e. self lubricating and tough.

I don't think UHMW has anywhere near the compression strength and stiffness of brass, so it may not help much and just deform under the pressure.

[ShopRat42]

I don't think UHMW has anywhere near the compression strength and stiffness of brass, so it may not help much and just deform under the pressure.

Hmm, good point. I was thinking you could tighten it up quite a bit because of its slippery nature but brass is probably the way to go. Well looks like I have to do a test.

[BlackICE1]

After thinking about a lot of different options to stiffen the milling head, I believed I settled on the final idea. The goal is to somehow tie in the head to to Patriot's base in a way to maximize Y and Z stiffness. X seems pretty stiff from my crude measurements. The stock 5th are is OK in the Z direction but does ZERO for the Y direction and being tied to the base through the stand leaves a lot to be desired even for Z.

My idea is to use the base of the tail-stock to mount a 3.5x3.5x0.188 steel tube welding to a steel base that bolts up to the tail-stock base' using the 4 existing mounting holes. Next replace the steel plate that the motor mounts to and replace it with a 2x6x0.188 steel tube that will be much stiffer than the plate. To that I will weld other pieces of steel to extend one end of the plate about -6" in Y to meet up with the tail-stock column. The two will be tied together with a bolted clamp the same as the stock 5th column Tying the 5th column directly to the base via the tail stock base is the stiffest way to do it. Mounting the column to the stand will flex the stand until the load is transfered to the base.

Opinions are welcomed before I get started down the wrong path.

[smallblock]

The Chinese built a copy machine like that years ago with the column mounted to the tailstock with an adjustable column so the tailstock could be moved. It was never picked up on by any of the big tool companies, so maybe the idea is not a good one. If you want to attach to the main bed of the machine, a support bolted to the end of the main column would be the most practical. As long as the opening was made so the tailstock could still slide off.

[walters474]

I've never had a good look at a Patriot, but for stiffening my Eldorado's mill bridge, I sandwitched a stack (as needed) of parallels between the 4 column mounting plate and tightened the mill bridge lift plate tight against the parallels which makes for a stiff mill head. This is also a good way to tram, the Y axis first, place shim ( or feeler guage) in center of one stack of parallels, and, for the X axis shim the appropriate end of the other stack of parallels and repeat as necessary (takes care of the sag on the fifth column side). Add or remove parallels, as needed when changing bridge height.
( I just noticed that all of the L's in parallel are in parallel

[BlackICE1]

What I am planning to do is similar to what the previous model did. But I will build a much stiffer 5th column, a 3x5x0.25 tube that bolts onto the tailstock's base and replacing the flexible black steel plate with a 3x6x0.188 rectangular tube. The steel plate and 5th column in the photo is not very stiff in the Y direction. My calculations est. less than 0.0005 of flex on the 5th when 20 lbs is applied to the spindle with the mod. Of course the total flex will be much more from the twisting of the bed, and 4 rods holding the mill head and table movement etc.

[cbud]

...the new Mill Turn with 6 columns and a single casting is a big improvement over the Patriot design and they have also added a mounting point on each top corner so you can bolt the head frame to a wall. The standard DRO is a real nice feature and eliminated the need for all those dials, which I never used anyway.

@smallblock,
Would you say the 2016 mill turn improved design is a vast improvement over the Patriot?

I ask because I'm considering a lightly used Patriot 2014 for about a $2600 discount from a new 2016 model.
All the extras like cabinet, dro, oiler plumbing (which I do not have access to a larger mill to cut channels in ways) are no brainer tangible extras. But the 6 linear rail system seems like a substantial redesign. The old Patriot bridge design seems unchanged from 2006 to 2014.

What's your take on the stiffness, durability, serviceability, etc?

If anyone else has an opinion also, please share.

[BlackICE1]

6 small cross section rods on the mill turn isn't that stiff in the Y direction. each rod increases the stiffness additively, but increasing the cross section increases the stiffness by the cube.

Even so the mill turn is a big improvement in stiffness compare to the patriot since the mechanical advantage from long lever arm is practically removed. I have a 2014 Patriot and I'm disappointed with the lack of stiffness in the Y direction. However I'm confident I can improve it when I get around to modding it. I would say if you aren't willing to mod the Patriot get the mill turn, bigger center bore on the lathe and much stiffer milling out of the box. The only downside is the way to slow Z movement.. At 20"/min peck drilling is going to suck.

[cbud]

6 small cross section rods on the mill turn isn't that stiff in the Y direction. each rod increases the stiffness additively, but increasing the cross section increases the stiffness by the cube.

Even so the mill turn is a big improvement in stiffness compare to the patriot since the mechanical advantage from long lever arm is practically removed. I have a 2014 Patriot and I'm disappointed with the lack of stiffness in the Y direction. However I'm confident I can improve it when I get around to modding it. I would say if you aren't willing to mod the Patriot get the mill turn, bigger center bore on the lathe and much stiffer milling out of the box. The only downside is the way to slow Z movement.. At 20"/min peck drilling is going to suck.

I'm leaning toward a Mill Turn. Wish I could see on in the Phoenix area.

I'm not too concerned about the z speeds. I'm thinking quite an improvement can be made with gas struts and splitting 2 steppers for the Z, one on each screw and driving one off the 3.5amps on the A axis output. All just with milling new stepper mounts and before any major electronics upgrades. It wont get 150ipm but that heavy casting, motor, and maybe a pdb add on are not light weight.