Pillar Drill Chuck Keeps Dropping Off ?

[The Coal Man]

Hi,

I am trying to drill 11mm holes in 4mm mild steel plate using a Record pillar drill (mid 1990's model) but the drill chuck keeps dropping off or losing traction with the spindle and stalling in the work. My technique is to drill a 4mm hole first then step up to the 11mm hole and spray the work with a coolant. When drilling the 11mm hole I am periodically backing up the drill to give a spray with the coolant then back on to the drilling.

I assume the chck dropping off is possibly due to my technique being wrong or its just a moderate drill and not really up to the job of 11mm holes in 4mm mild steel plate. I am using a Bosch HSS-R drill bit but tried it with a De Walt Extreme2 HSS-G drill bit which caued the chuck to stall or drop every time at the 11mm hole stage.

For the 4mm hole there is not a problem, its only when I step up to the 11mm hole after drilling the 4mm pilot hole that I get the problems.

Any advice most appreciated.

Thx

 

[Shox Dr]

Do you mean the chuck is coming off the taper

 

[rtbcomp]

Make sure the taper(s) are spotlessly clean. I think they also have to be dry, no oil or grease, but I'm open to correction on that point.

My Clarke pillar drill did that a lot, in the end I scrapped it, but that's a bit drastic at this stage.

 

[Shox Dr]

Make sure the taper(s) are spotlessly clean. I think they also have to be dry, no oil or grease, but I'm open to correction on that point.

My Clarke pillar drill did that a lot, in the end I scrapped it, but that's a bit drastic at this stage.

Dry

 

[The_Yellow_Ardvark]

Couple of tips.
I am on the phone so reading past post is difficult.

Make sure the taper is dry an clean.
When you re fit, bounce the chuck up and down, gently on a block of wood to seat it.

I had, in the past, had a pillar drill (One on the floor) hat was in the shop I was using do the same.
A clean and tap and we were well away.

 

[penfold]

If there's grot on the taper or the socket give them a fettle with wire wool and some oil(wd40 etc), then clean off and reassemble followed by giving it a wallop with a mallet or lump of wood to drive it home.

 

[ukracer]

Couple of tips.
I am on the phone so reading past post is difficult.

Make sure the taper is dry an clean.
When you re fit, bounce the chuck up and down, gently on a block of wood to seat it.

I had, in the past, had a pillar drill (One on the floor) hat was in the shop I was using do the same.
A clean and tap and we were well away.

How the he'll are you multitasking.

As for the OP if you can get a morse reamer you could gently clean it up inside.

 

[rikrobson]

Assuming that the taper and bore are clean, one or both will be damaged or out of whack. If its the chuck then another chuck will prove that if you have one.
you'll be able to lap the chuck on the taper. bear in mind this will mate the two and will affect the taper, so you'll find it difficult to put another chuck on.

 

[Wendelspanswick]

What speed are you using for the 11mm drill?
And is the workpiece clamped to the table or just held, it could be if you are free drilling the pilot hole and then the larger hole the alignment has changed, sideloading the chuck and forcing it off its taper.

 

[The Coal Man]

Do you mean the chuck is coming off the taper

Yes, the chuck is coming off the taper.

 

[The Coal Man]

What speed are you using for the 11mm drill?
And is the workpiece clamped to the table or just held, it could be if you are free drilling the pilot hole and then the larger hole the alignment has changed, sideloading the chuck and forcing it off its taper.

I am using 540rpm for the 11mm hole and used 1100mm for the 4mm hole. The workpiece is clamped to the table with 2 G clamps

 

[The Coal Man]

Going back to some previous comments about the chuck and taper being dry, there seems to be a thin film of oil on the taper. I will clean it off with acetone and also the inside of the chuck and then locate it using the block of wood method.

Many thanks for all of your replies, I will report back after cleaning and testing again.

Thx

 

[MBB]

Same thing happened to me it was the tapers fault. I blued the taper on a new drill bit and found the taper was out of tolerance on the drilling machine.
The solution was to turn a groove on the chuck morse taper about .030" deep half inch long in the middle of the taper, after doing this the chuck never dropped out again.
You may have seen this groove on some commercial morse tapers.

MBB

 

[Seadog]

You should be cutting at around 350 for that size in a free cutting mild steel. AS I said previously, don't increase in steps from 4mm, go straight to 11mm. Does the chuck fit on a male taper on the quill or is it a Morse fitting?

 

[The Coal Man]

You should be cutting at around 350 for that size in a free cutting mild steel. AS I said previously, don't increase in steps from 4mm, go straight to 11mm. Does the chuck fit on a male taper on the quill or is it a Morse fitting?

Unfortunately, the lowest speed on the drill is 540rpm so I am restricted to that for the 11mm cut.

I'm lost through not knowing what a morse fitting is. The taper is in my eyes male and the chuck just slides onto it. In the manual it says the spindle type is JT6. The tapered part that the chuck slides onto is approximately 2 inches long.

What speed are you using for the 11mm drill?
And is the workpiece clamped to the table or just held, it could be if you are free drilling the pilot hole and then the larger hole the alignment has changed, sideloading the chuck and forcing it off its taper.

I think you might have a good point here. When changing the drill bit from 4mm to 11mm I have to lower the table or swing it to one side in order to get the 11mm drill bit into the chuck. I then relocate the table as best as I can to centre the 11mm drill bit onto the 4mm hole. However, I accept that I am never going to get it perfectly centred but I check it from several directions to get it as best I can.

The drill only has 50mm of travel so I have to get the table out of the way to be able to swap over the drill bits. The difference in length between the 4mm and the 11mm drill bits and the travel required makes it a requirement to adjust the drill table. Hopefully, I am getting the 11mm drill bit centred close enough to avoid sideload?



I could just "go for it" and try the De Walt Extreme2 11mm HSS-G drill bit at 540rpm without the 4mm pilot hole but I have another 10 holes to drill. My local Machine Mart has some Heller HSS-Cobalt bits in stock, perhaps one of these would be a better option than my Bosch HSS-R 11mm bit or my De Walt Extreme2 HSS-G 11mm bit


Rgds

 

[ukracer]

Unfortunately, the lowest speed on the drill is 540rpm so I am restricted to that for the 11mm cut.

I'm lost through not knowing what a morse fitting is. The taper is in my eyes male and the chuck just slides onto it. In the manual it says the spindle type is JT6. The tapered part that the chuck slides onto is approximately 2 inches long.





I think you might have a good point here. When changing the drill bit from 4mm to 11mm I have to lower the table or swing it to one side in order to get the 11mm drill bit into the chuck. I then relocate the table as best as I can to centre the 11mm drill bit onto the 4mm hole. However, I accept that I am never going to get it perfectly centred but I check it from several directions to get it as best I can.

The drill only has 50mm of travel so I have to get the table out of the way to be able to swap over the drill bits. The difference in length between the 4mm and the 11mm drill bits and the travel required makes it a requirement to adjust the drill table. Hopefully, I am getting the 11mm drill bit centred close enough to avoid sideload?



I could just "go for it" and try the De Walt Extreme2 11mm HSS-G drill bit at 540rpm without the 4mm pilot hole but I have another 10 holes to drill. My local Machine Mart has some Heller HSS-Cobalt bits in stock, perhaps one of these would be a better option than my Bosch HSS-R 11mm bit or my De Walt Extreme2 HSS-G 11mm bit


Rgds

Some photos might help....

 

[The Coal Man]

Some photos might help....

I have just cleaned the taper and chuck with acetone and tapped it back on by descending it onto a block of wood. A photo would only show the chuck back on the taper. If it drops off again I will take a photo.

 

[Seadog]

If you've a lead or copper mallet use that. Make sure the jaws are withdrawn inside the chuck body first.

 

[ukracer]

I have just cleaned the taper and chuck with acetone and tapped it back on by descending it onto a block of wood. A photo would only show the chuck back on the taper. If it drops off again I will take a photo.

Understood. The reason I suggested it was because of this comment.

"
I'm lost through not knowing what a morse fitting is. The taper is in my eyes male and the chuck just slides onto it. In the manual it says the spindle type is JT6. The tapered part that the chuck slides onto is approximately 2 inches long."

The way I read what you say is the chuck is falling off......and results in nothing left stuck into it? Which means the problem part is not "Morse"

 

[The Coal Man]

If you've a lead or copper mallet use that. Make sure the jaws are withdrawn inside the chuck body first.

Done, I used a block of wood on the table and lowered the chuck onto it a few times, the jaws were withdrawn inside the chuck body.

I am undecided if I should just "go for it" and try the 11mm hole without 4mm pilot or go back to the 4mm pilot scaling up to 11mm now that I have cleaned up the taper and chuck. The 540rpm lowest speed restrictance with the drill is leaning me towards the 4mm pilot then the 11mm. I think if I "go for it" at 540rpm for the 11mm hole without a pilot hole I have a high chance of blunting the bit?

Rgds