New Mill

[david pierce]

Tom,
I still can not imagine the spindle itself wobbeling. Any time a tool is inserted into the spindle, the ID of the spindle must be wiped clean. The R8 tool itself must be wiped clean with a rag. I always used my t-shirt. I always cleaned out the spindle ID with my finger by sticking my finger into the spindle hole and rotating the spindle (BY HAND) to clean out any debris. If a tool was forced in that was not lined up with the internal key that could have damaged the spindle internally. Check out the inside of the spindle with a mirror and a flashlight. Any piece of anything wegded between the tool and the spindle ID will cause the tool to wobble. Again, check the spindle by itself for any runout problems.
david

[tmac1956]

david:

OK. First, I tightened the heck out of the spindle nut with the spanned wrench which came with the machine. I have done this before but never with this much force. Then I went through and checked the following with the gage. Here’s the results.

1) Checked inside the spindle with dental mirror – no debris. Cleaned with alcohol and lint free rag anyway.

2) Just about no run out on outside of spindle +- 0.0005” +-0.001” run out inside spindle

3) Cleaned and inserted 3/8” end mill holder with 3/8” end mill. +- 0.0005” run out on face of holder and +-0.001” run out

3) Cleaned and inserted 1/4” R8 Collet holder with 1/4” drill bit. +- 0.0005” run out on drill bit shank

4) Cleaned and inserted 0-1/4” ball bearing Jacobs chuck with 1/4” drill bit. Run out on drill bit shank +-0.0005”

5) Cleaned and inserted 1/4-1/2” drill chuck that came with the machine. Run out on drill bit shank +-0.002” (This thing has an obvious visual wobble)

To me, these numbers sound pretty darn good. The only thing I can think of that is different is the tightening of that nut. However, The tech guy told me that doing this would have no effect on the shaft alignment in the vertical.

I will be the first to say that my lack of experience could easily be responsible for the screwed up the drilling results. That, plus the obvious visual wobble of the locking bold and the big chuck that came with the machine are probably responsible.

What do you think? I do NOT want to have to crate this thing back up if I don’t need to.

Thanks!
Tom

[tmac1956]

Let me try this again with a little better typing…

1) Checked inside the spindle with dental mirror – no debris. Cleaned with alcohol and lint free rag anyway.

2) Just about no run out on outside of spindle +- 0.0005”; +-0.001” run out inside spindle

3) Cleaned and inserted 3/8” end mill holder with 3/8” end mill. +- 0.0005”;run out on face of holder ; +-0.001” run out on mill shank

3) Cleaned and inserted 1/4” R8 Collet holder with 1/4” drill bit; +- 0.0005” run out on drill bit shank

4) Cleaned and inserted 0 to 1/4” ball bearing Jacobs chuck with 1/4” drill bit. Run out on drill bit shank +-0.0005”

5) Cleaned and inserted 1/4 to 1/2” drill chuck that came with the machine. Run out on drill bit shank +-0.002” (This thing has an obvious visual wobble)

[david pierce]

Tom,
If the mill spindle runs true and you have runout only after the chuck is inserted then the problem has to be with the chuck. Find a drill bit or a dowel pin that will fit properly into an R8 collet and put than into the spindle. If the runout is gone then there is definately a problem with the chuck. Was this an ENCO chuck and R8 chuck adapter or did it come with the mill. Separate the chuck and the adapter and put the adapter into the spindle hole. Check the runout on the Jacobs Taper of the adapter. If it is good then the problem is either with the chuck or the mounting of the chuck with the adapter. The chuck may be damaged. Have you ever hammered on the jaws of the chuck? Whenever you tap the chuck you should always retract the jaws into the body of the chuck and tap on the body only. Never the jaws.
Your Emai address at @wallace.edu bounced back for both Bob and me. Send Bob your correct Email address and get my phone number from him. Then give me a call tomorrow.
Also, if the spindle nut is too tight it will crunch your spindle bearings. The nut only needs to be tight enough to keep the spindle from moving under a cutting load.
david

[david pierce]

Tom,
I just read your new blog. It looks like the mill is OK but the drill chuck that came with the machine is not a super high precision item. It also looks like the Jacobs chuck and the collet have about the same runout; .0005 sounds pretty good to me. The wobble could have been caused by the drill bit. Did you center drill the spot first? Was it prick punched?. It is normal for a twist drill to skate around the surface of a plate if it used without center drilling the plate first. Drill bits are available that can be used without center drilling first and are called split point drill bits. They are much shorter than jobber length drill bits and are usually sold as individual sizes in packs of 12. Machine shops use them to save time because a center drill operation is not required. They are usually used on turret lathes (CNC) or CNC machining centers where operations are timed to seconds.
david

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