An FB-2 Mill Mod

[len]

The only mill I have is the one on my Maximat10P lathe, so I try to make the most of it. One of the mods I made is to equip it with a DC motor with speed control, which has worked out very well. But I have always had problems with rigidity on heavy cuts. I tracked the problem to the clamping arrangment on the block that rides on the column. The block is split on the bottom end and a bolt pinches it to the column. In order to reduce vibration the bolt has to be really torqued down--way too much for my tastes.

I pondered this problem for a while trying to find a simple solution. The easiest one that came to mind was a brass-tipped setscrew to help take up the play, but this solution didn't sit right with me. A better one was to extend the existing slot so the entire block was slit, and to install a second clamping bolt at the top of the block.

Although this seemed like the way to go, I was reluctant to cut the block. The reason is that I have a lot of misgivings about making irreversible changes to a macine tool. What if I was wrong about the source of vibration, or I screwed-up something else?

I pondered this solution for about a week and finally decided to go ahead with it. I approached the job with caution and a lot of nervousness, but the good news is that it went remarkably well. It was so simple to cut the block on my bandsaw (modified for metal-cutting) that I chided myself for not doing it earlier. The drilling and tapping operation went equally well. (Cast iron is very easy to cut, if you don't mind the mess.). It took me less than 2 hours to do the entire job!

So how does it work? Very well, indeed. It seems like the EMCO engineers weren't so good at designing this part. Curiously, the cast iron saddle that attaches the column to the lathe bed is split the entire length and uses two clamp bolts. Hmmm... wonder if a different engineer designed that piece..

len

PS, next mod is to automate the tedious head lifting mechanism. I'm really tired of cranking that leadscrew.

[willjordan]

Sounds like a good modification. The problem hasn't bothered me much on my V10, but I have been carefull not to push too hard when milling.

I have pondered doing something with the mill lead screw as well, but I haven't had the incentive to try anything. I've also considered putting a worm drive on the off end ot the sindle feed screw so I could use that advance for taling a last pass.

[Too_Many_Tools]

Hi Len,

How is this mill modification working out for you?

I had read your posting earlier but like you, I have serious reservations in making any permanent mod to a machine like an Emco.

Have you made any progress on the motorization of the mill height adjustment?

TMT

[len]

TMT,

The mod works fine and has made life a lot easier. Let me eleborate on my reasons for making the mod in the first place, as this will help you decide if you want to do it on your machine.

Before I made the mod, in order to secure the column slider to the column required way too much torque on the top bolt. If I didn't overtighten this bolt, I could always feel some movement between the slider and column if I placed my finger there during a heavy cut. This didn't seem right to me, so I decided to finish the slot that EMCO had stopped half way up the slider.

As to why EMCO chose to limit the slit halfway through the block, I can't really say. I'm sure there's a good reason, but I don't know what it is. It may be that they didn't want to disturb the vertical alignment of the mill head when it was clamped, and using only the bottom bolt to do the pinching was the way to achieve this. I'm guessing this is the reason because I now notice a slight shift of the head when I tighten the top bolt. On the other hand, it's now a lot easier to tighten the top bolt. You can prevent the head from shifting by keeping some clamping pressrue on the top bolt (that is, don't loosen it too much).

I find the mod has made my use of the mill much more enjoyable. One of my goals was to use speed handles on the mill head wherever possible (the newer mills have them). Without the mod, I could never have used one on the top bolt. The speed handles are a really nice addition to the mill

As to the power lift mod, I have a motor and a design but have not gone much beyond that. The mod to the slider block has made it much easier to lift and lower the head, so the power conversion doesn't have as muich priority. But I still plan on doing it.

len