Originally Posted by
spumco
I bought a BT30-90 spindle from Skyfire along with their PDB. PDB is a 2-stage matched to the spindle belleville stack. You can see both of them on their web site.
I tried working with the US distributor but he was a total flake - stopped returning my emails. I'm like "Hi, I have many American Dollars for you. Please answer one question, and I'll give them to you." cricket, cricket...
Wound up using the Canadian distributor - very nice guy - but I got hammered in customs and shipping 'cause he had to ship to Canukistan and then to the US. Just email Skyfire. They'll sell directly to you. No issues with delivery or so forth when they forgot to include the PDB mount - they also made me a custom 36T pulley for about $50. If you do buy something from them, make a big shopping list. The spindle is going to go freight and take a while, so you might as well get tool holders and anything else you think is sexy.
An alternative would be same thing from Alibaba or Aliexpress. There are a number of vendors offering BT-30 spindles - some seem crappy, some are using the Skyfire photos, and I believe Skyfire has a store on there as well. There are also air over hydraulic PDB's for very cheap.
This is not an insignificant upgrade. The spindle mounting hole will need to be bored from 80mm to 90mm, and the bolt pattern is different.
In addition, Skyfire has changed the head casting from the original Mikini. Close examination of Skyfire Instagram photos shows the head casting is now taller, has a thick circular boss on the bottom where the spindle mounts, and the top is open. Also there is a wide flange on the top where the 130mm (I'm guessing) servo spindle motor sits. They are using a thick plate on the top of the head casting to box everything in instead of the Mikini arrangement. That plate acts as a mount for the motor and PDB.
Minimum to accomplish using a 90mm Parker servo:
1. 3/4" plate on the bottom to drop the spindle down and reinforce the head casting where the spindle mounts. This will bolt to the casting and the spindle bolts will clamp through it to the casting.
2. Top plate, about 3/8" thick. Raises the PDB and motor so the motor shaft and spindle pulley are about the same height.
3. Motor sub-plate.
I still haven't figured out how to take the head off the column. I think I have to un-do the ball screw and slide it off as there's no access to the flanged rail trucks from the front.
Just to make it clear, I haven't done this upgrade yet. I figure my mill will be down for quite some time and I have a few thigns to make before wheeling it in to the ICU.
First thing to do is see if you can find a spindle that's the same length as the R8. If not, go to the Skyfire instagram page and look at some of the construction photos. Pay close attention to the details of the head - you'll see what I'm talking about.
I have some tentative models of the adapter bits if you're interested.