synthesist
So many knives so little time
- Joined
- Sep 14, 2004
- Messages
- 933
This is a discussion I've had over the past week about rebuilding a drillpress that I had with Scott (Ickie) Ickes (he KNOWS about bearings!). we thought some of you might find it helpful.
Syn
Originally Posted by synthesist
I read what you said about being a service rep for a bearing company with a grin and I have some questions for you...................
I am experiencing some runout on my (upgraded (( 1 hp Baldor motor)) and tuned ((much better synthetic belts and cast iron pulleys)) Craftsman 15" 12 speed drillpress which has served me well for a long time. When I check the Sears repair parts website they have regular ol' replacement bearings for the quill. But I'd like to upgrade these bearings because I'd like to use a mill/drill table which will increase the side stress on these bearings when I use an endmill to slot stuff. Soooooooooooo do you have any suggestions or advice on how to improve this machine?
Any thoughts (website or parts suppliers links for example) on this or on rebuilding a machine like this? I'd also be interested in getting a better chuck if I could figure out what would be a suitable replacement for the Sears stock unit. Any thoughts on how to tell what this one is?
I thought about posting this question but I wanted an answer from you specifically, we can, however, do this as a new post this if you wish.....................
Thanks in advance
Corey "synthesist" Gimbel
Scot replies:
Do you know the bearing part numbers? It's probably available in a precision grade that will have a higher rotational accuracy. As far as getting replacements, it's probably less expensive to go to a regular bearing supplier. In Oak Park, Illinois. You have the following bearing distributors nearby:
Motion Industries
3900 S. Cicero Avenue
Cicero, Illinois 60804
(708) 780-6200
Bearing Distributors Inc.
5480 W Roosevelt Rd.
Chicago, Illinois 60644
(773) 378-7200
Precision Industries
840 25th Avenue
Bellwood, Illinois 60104
(708) 544-9787
Now, how to tell if the bearing has a highly accurate rotational tolerance. I'm assuming that the bearings are ball bearings, which they usually are. If they're not then the following will not help you. If you respond with the part numbers, I'll be able to let you know exactly what to get to replace the bearings in your machine.
Our brand of ball bearing is Fafnir. If the bearing has a prefix containing the following, "MM" it is a super precision bearing that will hold down your run out tolerances. What you want is a bearing with ABEC-7 or ABEC-9 precision. These are the two prefixes that are most probable for what you're looking for.
MM=superprecision-ABEC 7
MMX=ultraprecision-ABEC 9
You can even increase the accuracy of your shaft during installation. These bearings are marked with the high point of runout. If you have access to a lathe, you can mount your shaft in the lathe and rotate it. With a dial indicator mounted against the shaft, you can read the high point of runout on the shaft. Install the bearing with it's high point of runout opposite to the high point of runout on the shaft. This will negate the inherent runout in the shaft and reduce it to the point of being insignificant.
If you wish to discuss further, feel free to contact me by phone at (330) 284-3103.
Scott (Ickie) Ickes
Scot adds:
One other thing. You will pay $$$ for increased precision. You can expect double the cost of a normal bearing and up to as much as 10X the cost. They ain't cheap.
Scott (Ickie) Ickes
Corey says:
Thanks for the "HIGHLY" informative reply. I will get the Sears/Craftsman part numbers and relay those tonight when I get home. I seem to remember something about "25mm" bearings and they only cost $8 or $10 from Sears plus shipping, of course.
I definitely want to upgrade the precision of this tool and cost is not a problem (I don't do this often) compared to starting over with a a different brand/higher quality machine. Getting the thing apart may be more of a challenge.
I have a different question though. I want to use this thing for "light" milling. I realize that is bit of a problem given how the chuck mounts and that it puts considerable side to side stress on the bearings. Are there bearings I could use to mitigate this? Thrust bearings perhaps? Just curious.
Thanks again
Corey "synthesist" Gimbel
Scot replies:
We'll see if the Sears part number helps me. It may not help. I'm hoping to get the ABMA part number. Sometimes, companies put only their part number on them so that you can't identify what it really is. This way they guarantee that they get all of the part sales.
As far as changing the bearings for light milling, I can't really help you with that. It's a trade off. If you change the load carrying capabilities to handle the side to side loads, you'll lose the load carrying capabilities to handle the loads from drilling. The bearings are probably angular contact bearings and will be able to handle some side to side loading, but I'd leave it as is and just be careful about keeping the loading "light" as you stated. Actually, "very light". A drill is not set up to be a milling machine.
Once we have the part numbers (hopefully), I'll be able to be more specific about what you'll be able to get away with.
Scott (Ickie) Ickes
Corey digs around and finds the number:
Okay I have all the numbers.................
The drillpress model # is 113.213853
The spindle assemble bearing #s and prices are:
BEARING, BALL 17MM (STANDARD HARDWARE ITEM - STD315225 ($6.99)
BEARING, BALL 25MM (STANDARD HARDWARE ITEM - STD315255 ($12.49)
BEARING, THRUST - 60503 ($19.49)
and
SPACER, BEARING - 71372 ($2.99)
I think that covers the things you asked about
Thanks again for your help.
Corey "synthesist" Gimbel
Scot replies:
Crap. Those are not recognized bearing numbers. As I feared, those are Sears numbers, or the numbers that Sears supplier uses to make sure that you have to buy their bearings. There is no way to upgrade your machine because of this, since I have no idea what bearing to tell you to ask for from a bearing supplier. I'm sorry to be the bearer of bad news.
Scott (Ickie) Ickes
Corey is depressed:barf: :
Okayyyyyyy then we tried.............. There is one last option, perhaps. What if I take it apart and take the bearings to one of the vendors you listed? Can the bearings be measured and matched from the dimensions? Just a thought.
Corey "synthesist" Gimbel
Scot (who realizes he's signed up for more then he realized says:
Not really. The bearings will have a radial load capacity and an axial load capacity. Just because the bearing fits in the hole, doesn't mean that it can carry the loads. However, if you take them out and the numbers on the bearings are different than the numbers that you gave me (in other words, if the "real" part numbers are on them) then we're in business.
Some things to pay attention to when removing them. If you don't want to ruin the current bearings, in case you want to re-use them....
If you drive them off of the shaft or out of the housing:
Hit them with a punch made out of keystock or cold rolled mild steel.
Do not use a harden punch.
Do not use heat to remove them.
If you use heat to install new bearings, put them in your kitchen oven at 250 degrees F. to install them on the shaft.
Do not freeze them in liquid nitrogen, to install them in the housing.
Do not hit the seals or cages.
If you drive them in or out, drive on the inner race if it's tight fit on the shaft.
Drive on the outer race if it's tight fit in the housing.
It will most likely be tight fit on the shaft (inner race), since the shaft is what is rotating in a drill.
You can hit it as hard as you want with keystock or cold rolled.
Use a bearing puller if you have one.
The reason that I tell you what race to hit, is because if you drive on the wrong race, you'll be forcing the load of the hammer blows through the rollers. With ball bearings, the rollers make point contact with the races and all the load of the hammer blows will through that single point contact, damaging the bearings.
Good luck. On a side note, I deal with bearings, equipment rebuild and equipment design and redesign every day. I personally wouldn't try this. I'd just buy a machine that is designed to do what you want to do. Just my humble opinion.
Scott (Ickie) Ickes
Corey surrenders - finally:
Eeeeeeeeeeeeeek
I think you're right, maybe I will pass on this project. I do appreciate all the wisdom and advice you've provided though. I see a small mill ( any suggestions on those? ) in my future and continuing to use this for wood which it works just fine for.........................
I think I'm going to post this whole thread which others may find HIGHLY informative also (unless you tell me not to. I can't imagine why you would but I thought I'd ask first anyway.
Corey "synthesist" Gimbel
Scot administers the coup de grace:
If you want to post it you may. It might be easier to post the following:
Don't try to modify equipment to do what it's not designed to do....because it's a nightmare. Just kidding.
Syn
Originally Posted by synthesist
I read what you said about being a service rep for a bearing company with a grin and I have some questions for you...................
I am experiencing some runout on my (upgraded (( 1 hp Baldor motor)) and tuned ((much better synthetic belts and cast iron pulleys)) Craftsman 15" 12 speed drillpress which has served me well for a long time. When I check the Sears repair parts website they have regular ol' replacement bearings for the quill. But I'd like to upgrade these bearings because I'd like to use a mill/drill table which will increase the side stress on these bearings when I use an endmill to slot stuff. Soooooooooooo do you have any suggestions or advice on how to improve this machine?
Any thoughts (website or parts suppliers links for example) on this or on rebuilding a machine like this? I'd also be interested in getting a better chuck if I could figure out what would be a suitable replacement for the Sears stock unit. Any thoughts on how to tell what this one is?
I thought about posting this question but I wanted an answer from you specifically, we can, however, do this as a new post this if you wish.....................
Thanks in advance
Corey "synthesist" Gimbel
Scot replies:
Do you know the bearing part numbers? It's probably available in a precision grade that will have a higher rotational accuracy. As far as getting replacements, it's probably less expensive to go to a regular bearing supplier. In Oak Park, Illinois. You have the following bearing distributors nearby:
Motion Industries
3900 S. Cicero Avenue
Cicero, Illinois 60804
(708) 780-6200
Bearing Distributors Inc.
5480 W Roosevelt Rd.
Chicago, Illinois 60644
(773) 378-7200
Precision Industries
840 25th Avenue
Bellwood, Illinois 60104
(708) 544-9787
Now, how to tell if the bearing has a highly accurate rotational tolerance. I'm assuming that the bearings are ball bearings, which they usually are. If they're not then the following will not help you. If you respond with the part numbers, I'll be able to let you know exactly what to get to replace the bearings in your machine.
Our brand of ball bearing is Fafnir. If the bearing has a prefix containing the following, "MM" it is a super precision bearing that will hold down your run out tolerances. What you want is a bearing with ABEC-7 or ABEC-9 precision. These are the two prefixes that are most probable for what you're looking for.
MM=superprecision-ABEC 7
MMX=ultraprecision-ABEC 9
You can even increase the accuracy of your shaft during installation. These bearings are marked with the high point of runout. If you have access to a lathe, you can mount your shaft in the lathe and rotate it. With a dial indicator mounted against the shaft, you can read the high point of runout on the shaft. Install the bearing with it's high point of runout opposite to the high point of runout on the shaft. This will negate the inherent runout in the shaft and reduce it to the point of being insignificant.
If you wish to discuss further, feel free to contact me by phone at (330) 284-3103.
Scott (Ickie) Ickes
Scot adds:
One other thing. You will pay $$$ for increased precision. You can expect double the cost of a normal bearing and up to as much as 10X the cost. They ain't cheap.
Scott (Ickie) Ickes
Corey says:
Thanks for the "HIGHLY" informative reply. I will get the Sears/Craftsman part numbers and relay those tonight when I get home. I seem to remember something about "25mm" bearings and they only cost $8 or $10 from Sears plus shipping, of course.
I definitely want to upgrade the precision of this tool and cost is not a problem (I don't do this often) compared to starting over with a a different brand/higher quality machine. Getting the thing apart may be more of a challenge.
I have a different question though. I want to use this thing for "light" milling. I realize that is bit of a problem given how the chuck mounts and that it puts considerable side to side stress on the bearings. Are there bearings I could use to mitigate this? Thrust bearings perhaps? Just curious.
Thanks again
Corey "synthesist" Gimbel
Scot replies:
We'll see if the Sears part number helps me. It may not help. I'm hoping to get the ABMA part number. Sometimes, companies put only their part number on them so that you can't identify what it really is. This way they guarantee that they get all of the part sales.
As far as changing the bearings for light milling, I can't really help you with that. It's a trade off. If you change the load carrying capabilities to handle the side to side loads, you'll lose the load carrying capabilities to handle the loads from drilling. The bearings are probably angular contact bearings and will be able to handle some side to side loading, but I'd leave it as is and just be careful about keeping the loading "light" as you stated. Actually, "very light". A drill is not set up to be a milling machine.
Once we have the part numbers (hopefully), I'll be able to be more specific about what you'll be able to get away with.
Scott (Ickie) Ickes
Corey digs around and finds the number:
Okay I have all the numbers.................
The drillpress model # is 113.213853
The spindle assemble bearing #s and prices are:
BEARING, BALL 17MM (STANDARD HARDWARE ITEM - STD315225 ($6.99)
BEARING, BALL 25MM (STANDARD HARDWARE ITEM - STD315255 ($12.49)
BEARING, THRUST - 60503 ($19.49)
and
SPACER, BEARING - 71372 ($2.99)
I think that covers the things you asked about
Thanks again for your help.
Corey "synthesist" Gimbel
Scot replies:
Crap. Those are not recognized bearing numbers. As I feared, those are Sears numbers, or the numbers that Sears supplier uses to make sure that you have to buy their bearings. There is no way to upgrade your machine because of this, since I have no idea what bearing to tell you to ask for from a bearing supplier. I'm sorry to be the bearer of bad news.
Scott (Ickie) Ickes
Corey is depressed:barf: :
Okayyyyyyy then we tried.............. There is one last option, perhaps. What if I take it apart and take the bearings to one of the vendors you listed? Can the bearings be measured and matched from the dimensions? Just a thought.
Corey "synthesist" Gimbel
Scot (who realizes he's signed up for more then he realized says:
Not really. The bearings will have a radial load capacity and an axial load capacity. Just because the bearing fits in the hole, doesn't mean that it can carry the loads. However, if you take them out and the numbers on the bearings are different than the numbers that you gave me (in other words, if the "real" part numbers are on them) then we're in business.
Some things to pay attention to when removing them. If you don't want to ruin the current bearings, in case you want to re-use them....
If you drive them off of the shaft or out of the housing:
Hit them with a punch made out of keystock or cold rolled mild steel.
Do not use a harden punch.
Do not use heat to remove them.
If you use heat to install new bearings, put them in your kitchen oven at 250 degrees F. to install them on the shaft.
Do not freeze them in liquid nitrogen, to install them in the housing.
Do not hit the seals or cages.
If you drive them in or out, drive on the inner race if it's tight fit on the shaft.
Drive on the outer race if it's tight fit in the housing.
It will most likely be tight fit on the shaft (inner race), since the shaft is what is rotating in a drill.
You can hit it as hard as you want with keystock or cold rolled.
Use a bearing puller if you have one.
The reason that I tell you what race to hit, is because if you drive on the wrong race, you'll be forcing the load of the hammer blows through the rollers. With ball bearings, the rollers make point contact with the races and all the load of the hammer blows will through that single point contact, damaging the bearings.
Good luck. On a side note, I deal with bearings, equipment rebuild and equipment design and redesign every day. I personally wouldn't try this. I'd just buy a machine that is designed to do what you want to do. Just my humble opinion.
Scott (Ickie) Ickes
Corey surrenders - finally:
Eeeeeeeeeeeeeek
I think you're right, maybe I will pass on this project. I do appreciate all the wisdom and advice you've provided though. I see a small mill ( any suggestions on those? ) in my future and continuing to use this for wood which it works just fine for.........................
I think I'm going to post this whole thread which others may find HIGHLY informative also (unless you tell me not to. I can't imagine why you would but I thought I'd ask first anyway.
Corey "synthesist" Gimbel
Scot administers the coup de grace:
If you want to post it you may. It might be easier to post the following:
Don't try to modify equipment to do what it's not designed to do....because it's a nightmare. Just kidding.
.I am a machinery builder so we have to modify stuff everyday and yes it can be a nightmare even for those experienced at it.In general though it's a much better idea to buy the right tool if ones available than to modify one for a different purpose.Dave
