I purchased an old Kearney and Trecker 3B Plain Horizontal mill with three different overarm supports and some random basic tooling for about double scrap price last year. I was excited to try to bring something made 80 or more years ago back to routine use (no serial number located - researched with limited success and believe it was made in the late twenties into the thirties). It had been sitting for years in a barn, and after cleaning it and figuring out how to change speeds and feeds was pleased to find everything appears to work including the oiling system and coolant. The table, saddle and knee move without excessive slop or too much backlash. The spindle has about .015" run out at the spindle measured from the variety of arbors and tool holders that came with it. I do not have a dial indicator that will fit far enough into the bore to determine if there is a single high spot or the whole shaft is bent. In case there was a burr or debris in the spindle bore I bought nice used #12 Brown and Sharpe hand reamer. There was very little improvement in run out after several attempts to ream the bore. The mill loads and unloads the cutter so much on each revolution that it sets up a slow vibration or oscillation with a new 2" wide HSS helical shell mill I chose to try on a mild steel block. I can't work around it despite changes in feeds,speeds, or depth of cut.
I thought about taking the compound slide off my big lathe and attaching to the mill table and using a boring bar to attempt to make things true, but the low spindle speed would likely create a very poor finish even if I got the taper right. Does it have to be ground rather than bored to be done properly?
I would appreciate advice on the correct approach to fixing this problem. Do I have to take the shaft out of the machine to repair it properly? If I am going that far should I consider making a new shaft with a more modern taper that has more tooling readily available (BT40 or similar). I don't mind spending a little coin and decent effort to return this machine to work, but at some point it becomes foolish (may be there already depending on your perspective). I know myself well enough that once it comes apart I will be on the slippery slope of a full tear down and rebuild - only to have a machine with no rapid feeds, no vertical head (unless someone has one laying around ), and more time and money into it than buying a much newer mill - and all the time without a working horizontal mill in house.
Anyone have a line on a book for this machine?
Thanks for the help!
I thought about taking the compound slide off my big lathe and attaching to the mill table and using a boring bar to attempt to make things true, but the low spindle speed would likely create a very poor finish even if I got the taper right. Does it have to be ground rather than bored to be done properly?
I would appreciate advice on the correct approach to fixing this problem. Do I have to take the shaft out of the machine to repair it properly? If I am going that far should I consider making a new shaft with a more modern taper that has more tooling readily available (BT40 or similar). I don't mind spending a little coin and decent effort to return this machine to work, but at some point it becomes foolish (may be there already depending on your perspective). I know myself well enough that once it comes apart I will be on the slippery slope of a full tear down and rebuild - only to have a machine with no rapid feeds, no vertical head (unless someone has one laying around ), and more time and money into it than buying a much newer mill - and all the time without a working horizontal mill in house.
Anyone have a line on a book for this machine?
Thanks for the help!