Depth control on drill press keeps changing.

[Eugenius]

I recently bought a 1989 vintage Shopsmith in good shape and have have figured out most everything. However, the depth control on the drill press has baffled me. It seems to work okay on the first couple of holes but the holes get shallower and shallower as I go along. The depth stop is still stopping the movement but not as deep as before. My first idea was that the table was sinking but it seemed solid. So I used a stick to mark how high it was and drilled a few holes. The holes got shallower but the mark on the stick showed that the table was still exactly where it had been. Then I though the the bit might be getting pushed deeper into the chuck a bit. So I changed to a larger bit that seemed to bottom out in the chuck and drilled some holes in a piece of scrap lumber. Still the same issue with the holes getting shallower.

So now I'm thinking it's user error, that is, my fault. Here's what I've been doing.
Extend the quill so the the bit is at the depth I want.
Lock the quill to hold the bit at that depth.
Lock the feed stop.
Release the quill lock. The quill retracts normally.
I extend the quill to check -- and it stops exactly at the depth I want.
I drill a few holes. The first few are okay but by the fourth or fifth one, the cut is shallower.
Note that I get the same problem -- shallower and shallower holes -- wherever I set the dial by the feed stop.

So am I doing something wrong?

If I am doing it right, what else should I check?

[algale]

If the table isn't sinking (which is an issue on occasion), is the headstock rising (being pushed up)?

[JPG]

Rising headstock????

I would guess a slipping quill stop or improper setting of the stop.(it is somewhat counter intuitive)

Let's eliminate the improper part first.

Lower the quill/bit/whatever to the position the stop is desired.

Loosen the quill stop wing nut and rotate the dial until it stops (AT 0).

Tighten the wing nut and retract the quill. The dial will indicate(*) the distance it will travel from retracted (up) position.

When drilling, the dial will read a decreasing value as the quill is advanced until it reaches the stop which should indicate "0".

After drilling a few holes check the reading at the retracted(up) position. It should be the same as above(*). If not, the quill stop is slipping and I would then suspect the serrated/tongued washers are not installed correctly. If it(*) is the same and the hole depth is getting shallower, then the table(or the headstock) is slipping.

The third possibility is all is ok and procedure was the culprit.

[Eugenius]

Thanks. I'll try that later and let you know.. (My SS is back in saw mode and I'm busy elsewhere today.)

By the way, what is the right way for the 2 tongue washers to be installed? Mine are installed so that the serrated sides face each other.

[charlese]

Seems we are forgetting the possibility of the drill bit slipping in the chuck.
Although maybe not necessary, I will remind of the best drill chuck procedure:

- after making sure the drill bit is centered in the chuck, hand tighten the chuck
- using the chuck key, lightly tighten the chuck in one of its key noles
- hand rotate the chuck and lightly tighten in the second key hole
- hand rotate the chuck again and lightly tighten in the third key hole
- rotate once more and you should find the key will not tighten any more and the bit is secure.

NOTE: You will notice as you progress from one key hole to the next there will be increasing resistance to tightening the key.

[JPG]

Thanks. I'll try that later and let you know.. (My SS is back in saw mode and I'm busy elsewhere today.)

By the way, what is the right way for the 2 tongue washers to be installed? Mine are installed so that the serrated sides face each other.

QUILL SERRATED WASHERS.jpg (9.55 KiB) Viewed 23295 times

Washers (36) serrated sides face the 'dial' (34).

[jsburger]

Seems we are forgetting the possibility of the drill bit slipping in the chuck.
Although maybe not necessary, I will remind of the best drill chuck procedure:

- after making sure the drill bit is centered in the chuck, hand tighten the chuck
- using the chuck key, lightly tighten the chuck in one of its key noles
- hand rotate the chuck and lightly tighten in the second key hole
- hand rotate the chuck again and lightly tighten in the third key hole
- rotate once more and you should find the key will not tighten any more and the bit is secure.

NOTE: You will notice as you progress from one key hole to the next there will be increasing resistance to tightening the key.

I don't want to hijack this thread but please someone who really knows tell me why or why not this procedure with a drill chuck is desirable or necessary. I have never used this "method". If this is so important why do key-less chucks work just fine? In my opinion this is just an old wives tale. There is no relationship between the three jaws of a drill chuck and the three holes for the key except that they are both three. When the chuck is tightened either by hand or the key, all three jaws move at the same time. The three holes for the key are just there for convenience so no matter the position of the chuck one of the holes is easily accessible.

[JPG]

Seems we are forgetting the possibility of the drill bit slipping in the chuck.
Although maybe not necessary, I will remind of the best drill chuck procedure:

- after making sure the drill bit is centered in the chuck, hand tighten the chuck
- using the chuck key, lightly tighten the chuck in one of its key noles
- hand rotate the chuck and lightly tighten in the second key hole
- hand rotate the chuck again and lightly tighten in the third key hole
- rotate once more and you should find the key will not tighten any more and the bit is secure.

NOTE: You will notice as you progress from one key hole to the next there will be increasing resistance to tightening the key.

I don't want to hijack this thread but please someone who really knows tell me why or why not this procedure with a drill chuck is desirable or necessary. I have never used this "method". If this is so important why do key-less chucks work just fine? In my opinion this is just an old wives tale. There is no relationship between the three jaws of a drill chuck and the three holes for the key except that they are both three. When the chuck is tightened either by hand or the key, all three jaws move at the same time. The three holes for the key are just there for convenience so no matter the position of the chuck one of the holes is easily accessible.

Well it may be an old wive's tale if thee are an old wife.

For 'typical' hobbyist use, it may not make any difference. A typical hobbyist set of drill bits contain some that are booggered up due to slipping in the chuck, and that is caused by insufficient holding power of the chuck which is in turn the result of insufficient equally distributed tightening of the three jaws.

Now a machinist will invariably ALWAYS tighten 'all the way around'(at least once) and will likely not have any( or at least only a few) buggered shafts on their drill bits. Those that are booggered are likely the result of NOT tightening all the way around.

Now this ignores the hex or three flat bits which do not require strict tightening of the chuck.

Personally I have booggered up enough bits that I now always go at least once around. I have a couple of older worn jacobs chucks that I will go around at least twice. Only when no discernible movement is detected will I quit.

Now if thee is only drilling wood and are using relatively small bits it probably does not matter.

I like all my bit shafts to be as close to new condition as I can. I really get angry with myself when I do boogger one.

I have insufficient 'successful' experience with 'keyless' chucks to have a positive opinion of them. What little experience I have had is not positive.

[jsburger]

Seems we are forgetting the possibility of the drill bit slipping in the chuck.
Although maybe not necessary, I will remind of the best drill chuck procedure:

- after making sure the drill bit is centered in the chuck, hand tighten the chuck
- using the chuck key, lightly tighten the chuck in one of its key noles
- hand rotate the chuck and lightly tighten in the second key hole
- hand rotate the chuck again and lightly tighten in the third key hole
- rotate once more and you should find the key will not tighten any more and the bit is secure.

NOTE: You will notice as you progress from one key hole to the next there will be increasing resistance to tightening the key.

I don't want to hijack this thread but please someone who really knows tell me why or why not this procedure with a drill chuck is desirable or necessary. I have never used this "method". If this is so important why do key-less chucks work just fine? In my opinion this is just an old wives tale. There is no relationship between the three jaws of a drill chuck and the three holes for the key except that they are both three. When the chuck is tightened either by hand or the key, all three jaws move at the same time. The three holes for the key are just there for convenience so no matter the position of the chuck one of the holes is easily accessible.

Well it may be an old wive's tale if thee are an old wife.

For 'typical' hobbyist use, it may not make any difference. A typical hobbyist set of drill bits contain some that are booggered up due to slipping in the chuck, and that is caused by insufficient holding power of the chuck which is in turn the result of insufficient equally distributed tightening of the three jaws.

Now a machinist will invariably ALWAYS tighten 'all the way around'(at least once) and will likely not have any( or at least only a few) buggered shafts on their drill bits. Those that are booggered are likely the result of NOT tightening all the way around.

Now this ignores the hex or three flat bits which do not require strict tightening of the chuck.

Personally I have booggered up enough bits that I now always go at least once around. I have a couple of older worn jacobs chucks that I will go around at least twice. Only when no discernible movement is detected will I quit.

Now if thee is only drilling wood and are using relatively small bits it probably does not matter.


I like all my bit shafts to be as close to new condition as I can. I really get angry with myself when I do boogger one.

I have insufficient 'successful' experience with 'keyless' chucks to have a positive opinion of them. What little experience I have had is not positive.

Probably true but that does not mean it is necessary on a drill chuck (Jacobs).


Oh, how I agree with you. Although I will say it has not happened very often and likely operator error in my case.

You still have not explained what the geometry of a 3 jaw drill chuck makes it important to tighten in all three key holes. There is no relationship between the three jaws and the three key holes.

[thunderbirdbat]

I don't want to hijack this thread but please someone who really knows tell me why or why not this procedure with a drill chuck is desirable or necessary. I have never used this "method". If this is so important why do key-less chucks work just fine? In my opinion this is just an old wives tale. There is no relationship between the three jaws of a drill chuck and the three holes for the key except that they are both three. When the chuck is tightened either by hand or the key, all three jaws move at the same time. The three holes for the key are just there for convenience so no matter the position of the chuck one of the holes is easily accessible.

Well it may be an old wive's tale if thee are an old wife.

For 'typical' hobbyist use, it may not make any difference. A typical hobbyist set of drill bits contain some that are booggered up due to slipping in the chuck, and that is caused by insufficient holding power of the chuck which is in turn the result of insufficient equally distributed tightening of the three jaws.

Now a machinist will invariably ALWAYS tighten 'all the way around'(at least once) and will likely not have any( or at least only a few) buggered shafts on their drill bits. Those that are booggered are likely the result of NOT tightening all the way around.

Now this ignores the hex or three flat bits which do not require strict tightening of the chuck.

Personally I have booggered up enough bits that I now always go at least once around. I have a couple of older worn jacobs chucks that I will go around at least twice. Only when no discernible movement is detected will I quit.

Now if thee is only drilling wood and are using relatively small bits it probably does not matter.


I like all my bit shafts to be as close to new condition as I can. I really get angry with myself when I do boogger one.

I have insufficient 'successful' experience with 'keyless' chucks to have a positive opinion of them. What little experience I have had is not positive.

Probably true but that does not mean it is necessary on a drill chuck (Jacobs).


Oh, how I agree with you. Although I will say it has not happened very often and likely operator error in my case.

You still have not explained what the geometry of a 3 jaw drill chuck makes it important to tighten in all three key holes. There is no relationship between the three jaws and the three key holes.

I always thought it was technique/habit building for when you moved on to larger chucks where the jaws are individually tightened. I was also taught that it would allow you to check to see if the bit was off center or had a large amount of run out.