Lms 3990 Mini Mill... Upgrades

You should immediately add a DRO since it makes the machine soooooooooooooooo much nicer to use. Check out the Android tablet based TouchDRO system. It's inexpensive to make, very full featured, and wonderful to us. Having a DRO is indescribably better than counting handwheel turns and dealing with backlash.

My other mods:
http://benchtopmachineshop.blogspot.com/

You can also build a nice power table feed for under $50. I also highly recommend modifying the gibs as it helps rigidity and makes it smoother. Also add a spindle light since it's pretty cheap and easy. But seriously, get a DRO.


Well, everyone suggests a DRO first. I have been milling on a manual floor model mill for years without DRO. But maybe I will consider it now. Thanks very much for your thoughts and ideas. I'll need to spend some time reading your link. Looks very interesting. Is the $50. powere feed and gibs modification in link?

danny
Laguna, Philippines
 
If I understand these modifications correctly,I don't think you could instal the dro sensor/bracket on Z column with the original torsion spring still in place, the gas spring should be installed first ,I copied and pasted the direction from Zoltan's link but I'm having a hard time understanding how he fitted the oval shaped UHMW in the base ,there's no pictures of the installation of it,which is unfortunate.


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.
I have seen a few youtube videos of this seemingly easy "gas strut/spring conversion" but none has a step by step direction on how to do it ,they all show the installation after it's done.
 
If I understand these modifications correctly,I don't think you could instal the dro sensor/bracket on Z column with the original torsion spring still in place, the gas spring should be installed first

Thanks Ken. That makes since what he says about the torsion spring. However, LMS shows the new version 3990 mill comes with a gas strut. Others here are mentioning an air spring. I'm wondering if the gas and air spring are one and the same?

BTW, I was looking at the Igaging DRO and looks like I'll be ordering them also.

danny
Laguna, Philippines
 
Intrepid, the air spring and gas strut is the same thing as far as I know ,even if there's a difference in mechanism,for this application it is one and the same.
The MLS 3990 does come with a gas spring already installed I have the 3960 with the older torsion spring but the only reason I am changing it is to install the DRO,I found a local vendor who sells them (IGaging)for under $150 in Canada, it seems to be as accurate as the newer model EZ View DRO.
I'll order mine after I replace the gas spring.
 
Intrepid, the air spring and gas strut is the same thing as far as I know ,even if there's a difference in mechanism,for this application it is one and the same.
The MLS 3990 does come with a gas spring already installed I have the 3960 with the older torsion spring but the only reason I am changing it is to install the DRO,I found a local vendor who sells them (IGaging)for under $150 in Canada, it seems to be as accurate as the newer model EZ View DRO.
I'll order mine after I replace the gas spring.

That's what I was thinking Ken. They are the same. So that is one mod I will not have to do. Seems like a good price for the IGaging DRO. I found a vender on flebay selling a three piece set, 6", 12", and 24" for $129.99 and free shipping in the US. $36.00+ for shipping to Canada.
 
I found that the air spring in my 3990 does make it quite smooth and easy to lower the head, but still a little harder going up since you are lifting the head. Im hoping it gets smoother as a I use it.
For mine I purhased the DROs from LMS while I was there picking up the machine. Still working on getting it all squared up and trammed. Cant wait to get to cutting.
 
I found that the air spring in my 3990 does make it quite smooth and easy to lower the head, but still a little harder going up since you are lifting the head. Im hoping it gets smoother as a I use it.
For mine I purhased the DROs from LMS while I was there picking up the machine. Still working on getting it all squared up and trammed. Cant wait to get to cutting.

I replaced the torsion spring on my 3960 to LMS air spring last week , the head on mine also is harder on the way up but as you mentioned it should get smoother with time and usage but overall, it's smoother than before and also a necessary upgrade (IMHO) to free up some space on the column for the Z axis DRO.

Today I spent a good 4-5 hours installing the X axis ,I already installed an Aluminum angle on the back of the bed , tomorrow I'll attach a bracket to the reader unit and the X axis will be done.
The Y and Z axes should be easier to install, I hope.
 
Im down with a bad flu for 7 days now. Not enuf energy to get to it for a few more days I think. All this sitting just gives more time to think and read tho.
 
There's a nasty flu bug going around this year, so far my wife and I haven't got it yet,(knock on wood), hope you get better soon.
 
If I understand these modifications correctly,I don't think you could instal the dro sensor/bracket on Z column with the original torsion spring still in place, the gas spring should be installed first ,I copied and pasted the direction from Zoltan's link but I'm having a hard time understanding how he fitted the oval shaped UHMW in the base ,there's no pictures of the installation of it,which is unfortunate.

I didn't really "fit" anything in the base. The UHMW was used to space the gas strut the correct distance from the base, the strut was then bolts to the UHMW, and then both were lowered down into the column.
 
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