|
|
Post by bobby1 on Dec 17, 2017 15:14:45 GMT -5
Where is the best place to get core drills?
Sintered or plated?
How do you determine the capacity of a drill press?
I have an old (late 50's) Homecraft drill press that has a 4" depth limit. It it considered a 4" drill press?
What should be the best speed to run a 4" or 5" core drill?
What would be the minimum horsepower for the drill press for doing 4" or 5" cores?
How do you hold the initial core while drilling the second and third corings?
Sorry for so many questions.
I'm tasked with selecting a sphere making machine and its accessories for our society's shop (which is also the local junior college's lapidary classroom).
Bob
|
|
vwfence
has rocks in the head
Member since January 2013
Posts: 566
|
Post by vwfence on Dec 19, 2017 8:26:39 GMT -5
I bought some from harbor freight . but I haven't sude them yet
|
|
minerken
Cave Dweller 
Member since August 2013
Posts: 466 
|
Post by minerken on Dec 19, 2017 13:31:02 GMT -5
more of a question than a solution but I've been trying to wrap my head around the need for a core to make a sphere. It seems that I have seen more just blocking out a square cut making a polyhedron when roughing out their spheres. I have tried making cuts from both a core shape and a block or cube and it seems that it was harder to get a good rough form from the cylinder than the cube(I was using a 3D modeling program to simulate the cutting). I realize that people do use cores but the cost of core bits the size you are suggesting are very expensive plus the added attachments like a water swivel (although that is not totally necessary) and then there is a group using it that are neophytes so to speak. As to your DP those are great old drills have one my self except it has a 13 or 14 inch through(i.e. quill length)as for HP you can drill pretty deep using the peck method but eventually torque will be a problem especially with a belt driven DP. In a past life I worked with a lot of core drilling in the mining industry and as a general rule of thumb cutting speeds were the harder the rock the slower the speed(rpm), down pressure should be such that you use enough to keep the rock and bit engaged but not enough to stall this means that having a variable speed is more advantageous than belt drives which you have to change. I know that there are many out there with a lot of experience using cores for spheres so I would love to know why they are preferred if that is the case.I don't want to hijack your thread but I thought that if there is someone that could explain this it might help making a decision.
|
|
Deleted
Deleted Member
Member since January 1970
Posts: 0
|
Post by Deleted on Dec 19, 2017 15:57:44 GMT -5
minerkenI have done it both ways. For a large operation that can afford autofeed drills, then the core method would be superior, by far. Standardized sizes and very little hand work would save tons of time, allowing for more spheres from fewer workers. 5 core cuts and into the sphere machine that is already set up for that size ball. Cubes require 18 saw cuts, allow for infinite sizes and some time hand grinding the polyhedron to near sphere before it goes in the machine. Maybe 10-40 minutes depends on size and material. The core drill is all manual for me. Takes the same labor and effort from me, as 18 saw cuts do. So no real benefit. Therefore I land back at the cube method. Plus agates don't core very well at all. Roger makes more spheres in a week than I have ever made. I'd love to here his input on this topic.
|
|
|
|
Post by rockpickerforever on Dec 19, 2017 16:43:40 GMT -5
minerken I have done it both ways. For a large operation that can afford autofeed drills, then the core method would be superior, by far. Standardized sizes and very little hand work would save tons of time, allowing for more spheres from fewer workers. 5 core cuts and into the sphere machine that is already set up for that size ball. Cubes require 18 saw cuts, allow for infinite sizes and some time hand grinding the polyhedron to near sphere before it goes in the machine. Maybe 10-40 minutes depends on size and material. The core drill is all manual for me. Takes the same labor and effort from me, as 18 saw cuts do. So no real benefit. Therefore I land back at the cube method. Plus agates don't core very well at all. @roger makes more spheres in a week than I have ever made. I'd love to here his input on this topic.
Maybe I shouldn't have passed up that brand new 4 inch diamond core drill at the swapmeet for $25. Hmmm. I knew it was a good deal (maybe worth $150?), but without much money in my pocket, $25 was ore than I had to spend. Oh well.
FYI, Roger is [@ vibratumble]. Awesome Petrified Colla Wood Sphere he recently did. The rest are pretty amazing, too, as are the shear numbers he has been turning out lately! You go, Roger!
|
|
minerken
Cave Dweller
Member since August 2013
Posts: 466
|
Post by minerken on Dec 19, 2017 16:50:25 GMT -5
@changing jobs! I think that you confirmed my suspicions, with the exception of automated shops in production mode which is fully understandable. Thanks!!! I hope this helps bobby1 with his original question |
|
|
|
Post by Lapidaryrough / Jack Cole on Jan 13, 2018 12:29:30 GMT -5
www.ohiopowertool.com/m-231-diamond-core-drills-core-bore-weka.aspx# Nice Core drill is Cheaper then a old HighLand-Park saw. 16" - 24" prices. / Milwaukee motors last. I have yet too smoke one. Not sure though a Ridgid 535 pipe threader motors run close to the same RPM. under $3500.00 plus drill bits. They make a great single cup Sphere cutting for roughing out blanks. Paul, in Lapidary Shop Help mag. From print - 1964. Paul made over 2000 spheres with a single cup grinder. His son built a stand for the some of the spheres using Leaf springs from old cars.
|
|
|
|
Post by Lapidaryrough / Jack Cole on Jan 13, 2018 12:40:54 GMT -5
i meant to say core drill for the blank yes two right angles drill points. Single cup to rough out is 80%-90% of the drilled blank.
then 50%-60% of diameter of blank as you work 80 grit mud on blank.
as the sphere starts to true to a sphere. switch to cups any type of machine 2 or 3 cup finish with 25% - 50% cups to the diameter of stone.
Paul made sphere cutting easy. It IS. Buy the tools and enjoy life. Looking back in time is a dead ended memory.
Don't buy junk.
Jack
|
|
|
|
Post by Rockoonz on Jan 13, 2018 12:44:47 GMT -5
How did the club decide making spheres in a club lapidary shop was a good idea? Unless your shop runs long hours and has a good area for an extremely messy operation I'm questioning the logic. I assume that a sphere machine was donated and that for some reason the club isn't going to sell it and buy more appropriate equipment for a public shop.
|
|
Deleted
Deleted Member
Member since January 1970
Posts: 0
|
Post by Deleted on Jan 13, 2018 22:00:30 GMT -5
How did the club decide making spheres in a club lapidary shop was a good idea? Unless your shop runs long hours and has a good area for an extremely messy operation I'm questioning the logic. I assume that a sphere machine was donated and that for some reason the club isn't going to sell it and buy more appropriate equipment for a public shop. Our club has a dozen maybe 15 machines. We all clean our mess after we are done. Sphere making is a great way to hook new members. Seems like they make a few balls then start doing other disciplines. Also,.they buy material to make the balls from. Profitable too! |
|
|
|
Post by Rockoonz on Jan 14, 2018 20:03:18 GMT -5
@shotgunner do they have a set-up guy on hand to keep the balls in the machines? From what I see hanging out with sphereguy you have to set them just tight enough to not squirt out but not so tight that they won't do the random spin action. Not a skill I've had any desire to master, especially when all I need to do is take a nice cube up to Matt and get a nice polished shot put.
Scott, have you ever done a thread on this shop? It sounds like it's about 8-10 x the little shop our club has up here. I'd love to find a way to help grow ours into something bigger and better, starting to get the kind of talent necessary, but there's some missing pieces.
|
|
Deleted
Deleted Member
Member since January 1970
Posts: 0
|
Post by Deleted on Jan 14, 2018 20:38:56 GMT -5
Each person man's their machines. I should do a thread on this club. It is by far the largest workshop I have ever ever seen. No doubt.
ETA, next time we go, I will image the club's facility and equipment. Thread coming soon. Before end of February.
|
|
|
|
Post by bobby1 on Jan 15, 2018 0:45:55 GMT -5
The classrooms that our club supports are at the Modesto junior College in Modesto, CA. We have had a working relationship with the college for about 35 years. We supply all the equipment, repairs and supplies. The school has classes in lapidary and jewelry making twice a day each for two days a week. A typical class has 12 to 16 students. Most students repeat the classes multiple times. We are going to buy the high speed Highland Park sphere maker for the classroom. The club gets use of the classrooms every Tuesday evening from 6:30 PM to 9:30 PM.
The biggest benefit we get from supporting the college comes in supplying us with new members. The instructor is a member of our club and she recruits about 4 or 5 new members (plus their family) every semester. This plus aggressive recruitment at our annual show has us significantly growing our membership. We are now the third largest club in the California Federation of Mineralogical Societies.
The classrooms for the lapidary activities have 10 dual wheel grinders, both diamond wheel and S/C wheels, 10 dual wheel expando sanding units and 8 polishing wheels. They have 10 trims saws. We just bought new 12", 14" and 18" Highland Park slabs saws for the classrooms. After our next show in early March we will be buying a new 24" Highland Park slab saw. The classrooms have been running on some quite old and high maintenance saws and we all will be happy to see them go away.
Bob
|
|
Deleted
Deleted Member
Member since January 1970
Posts: 0
|
Post by Deleted on Jan 21, 2018 19:54:06 GMT -5
The classrooms that our club supports are at the Modesto junior College in Modesto, CA. We have had a working relationship with the college for about 35 years. We supply all the equipment, repairs and supplies. The school has classes in lapidary and jewelry making twice a day each for two days a week. A typical class has 12 to 16 students. Most students repeat the classes multiple times. We are going to buy the high speed Highland Park sphere maker for the classroom. The club gets use of the classrooms every Tuesday evening from 6:30 PM to 9:30 PM. The biggest benefit we get from supporting the college comes in supplying us with new members. The instructor is a member of our club and she recruits about 4 or 5 new members (plus their family) every semester. This plus aggressive recruitment at our annual show has us significantly growing our membership. We are now the third largest club in the California Federation of Mineralogical Societies. The classrooms for the lapidary activities have 10 dual wheel grinders, both diamond wheel and S/C wheels, 10 dual wheel expando sanding units and 8 polishing wheels. They have 10 trims saws. We just bought new 12", 14" and 18" Highland Park slabs saws for the classrooms. After our next show in early March we will be buying a new 24" Highland Park slab saw. The classrooms have been running on some quite old and high maintenance saws and we all will be happy to see them go away. Bob Can anybody visit and pay a one day fee? How do you guys handle this? There is some work to re-organize our club and your input may be valuable. |
|
|
|
Post by Rockoonz on Jan 21, 2018 23:13:11 GMT -5
@shotgunner bobby1A thread devoted to club sponsored shops would be nice. Our little club shop has had it's own set of growth pains, and would be good to discuss what works and what doesn't. |
|
|
|
Post by bobby1 on Jan 24, 2018 11:55:27 GMT -5
Our use of the classrooms on Tuesday nights is for members only; however, if anyone is contemplating becoming a member they are welcome to stop by. We have some rather rigid requirements that the college requires. It includes the members only condition as well as we have to have well trained qualified monitors on hand at all times. We also have to comply with all the conditions that a regular college student must meet.
We have the funds to support the classrooms because of a high attendance at our annual show.
An additional benefit that we get is the support from the college students albeit many are members of our club. The students display about a dozen cases of their handiwork at the show. We give them a table to use to recruit new students at the show. Also, many of them do demonstrations at the show.
Which clubs are you with?
I'm the California Federation of Mineralogical Societies Membership Chairman so I do a lot of activities to help the various clubs increase membership as well as help them to identify and mentor people to step into club leadership positions.
Bob
|
|
zzyzzyx
having dreams about rocks
Member since October 2017
Posts: 60
|
Post by zzyzzyx on Feb 1, 2018 18:26:59 GMT -5
Nothing like that out here. Nothing
Good on you ole boy
|
|
