Thread: Accuracy in Drill Press a Quick fix

Hi Bruce
She's in good nick for 30 years old must be a dry shed, 5thou is probably not much more than when it was new.

Paul

That is exactly the same as mine, which I have also had for 30+ years, only difference is mine looks its age.
I have done that adjustment a number of times over the years, never been game to put the dial gauge on it though

HI,
That is something I was looking at doing to My DM-45 Mill Drill the other Day. The Quill on it does not have any Sideways movement, but the Cylindrical part of the Screw that goes into the Keyway Slot on the Quill is a reasonably bit smaller than the Slot. This allows the Quill to Rotate a little more than I would like. I need to make a New Screw for it, which reminds Me I must order the Grub Screw so I can make a New one.

Bruce,

I thought I'd have a fiddle with my drill after reading your post. There is about 7 thou quill slop with the quill fully extended. The Waldown has a pair of pinch bolts that enable the removal of some of the play but it's a fine line between loose and binding, I guess due to uneven wear of both the quill and cast iron head. With a Jacobs chuck fitted there is considerable runout, about 8 thou. I had commented a while back about the supremacy of the Jacobs Super Ball Bearing chuck. Well... I fitted the chuck in the lathe spindle and measured the runout 150mm from the spindle nose. 0.003". I then checked my seldom used Rohm Spiro keyless chuck, 0.001" TIR.

I inserted an indicator stylus inside the 3 Morse spindle bore and there was no more than 0.0005" runout in any position along the bore which leaves me stumped. I will try to reinsert the drill arbor in a position that minimises the runout. "Cancels" would be being a bit too optimistic.

I do have to be realistic, the drill is probably 40 years old and was in a very sorry state when I found it. It works well enough for my purposes and as I've mentioned previously, if I need an accurate hole, I'll use the mill.

Further to Paul's comment about your shed, I notice you have sarking under the roof cover. I didn't bother 25 years ago when I built mine. The lack of it combined with open eaves was a huge error.

BT

Bob
You have got me chasing the numbers on dial gauges, thanks for your interest.
Here are my results in the Hercus 260 headstock spindle, this morning.
No 4MT bore measures 1/2 thou max runout. When I am setting up 4C or 3C collets I have the collet inserts marked so that they go in to somewhat cancel out the error.
The drill chucks
Are all No 2 MT with sleeves to take them up to No 4 MT so there could be cumulative error in that assembly.
Results
"Rohm" keyless (generally used in the drill press) 5 thou runout
"Albrecht" keyless 2 thou runout
"Rabbit" brand keyed chuck from Hare & Forbes 1 thou runout.
I was very surprised to see this low price chuck come up so well. Its a fairly new item.
Which gets me thinking that drill chucks may get a bit of wear & strain over a period, that could lead to increased runout.
regards
Bruce
I purchased the "Rabbit" brand keyed chuck primarily for gripping threading taps in the tailstock.It has done a good job. I have a couple more of these in my Turret attachment, that fits on the lathe.

Interesting figures Bruce.

When I was making my 4140 tee nuts the other day, the M10 tap I used rotated in the ball bearing chuck. What is the largest tap you've successfully held with the Rabbit?

BT

Originally Posted by Anorak Bob

Interesting figures Bruce.

When I was making my 4140 tee nuts the other day, the M10 tap I used rotated in the ball bearing chuck. What is the largest tap you've successfully held with the Rabbit?

BT

Bob
I just refreshed the memory bu doing a few tests in the lathe. Have always had difficulty holding taps in the lathe.
The keyless chucks grip to a certain limit & then then the tap slips & the chuck also tightens, to the point where it cannot be undone with a hand grip, on the chuck.
That is why I purchased the "Rabbit" keyed chuck. OK it will hold up to 3/8th": BSW Taps without slipping.
However, in my trials anything over that size, no matter how tight the drill chuck may be on the tap, the No 2 morse taper in the tailstock will not grip sufficiently & all rotates. Not good.
My solution has been to start the tap in the lathe so its axially correct with the drilled hole, & then remove the workpiece to a vise & manually tap the thread in the conventional manner.
I did make up a simple tap holder with 3/4" OD steel with a hole drilled through its centre to suit the tap shank & 2 unbrako type 8-32 grubscrews fitted to make firm contact with 2 of the flats on the tap shank.
This worked exceptionally well in the turret attachment set up on the lathe, when I had batch runs to make of the same part.
So always searching for a better system. Perhaps a modification of the above holder with a rod protruding to make contact with the toolpost & prevent rotation might work.
regards
Bruce

You can be lucky with cheap drill chucks. I have two apparently identical keyed 1/2" chucks. One has - I forget - at least 5 thou runout, the other virtually none. I guess that makes me really lucky - I got both kinds of luck.