edstreet
Member
Sounds like a megga poll is in order that includes all the pen kits. 
TBC Bushings are comming
- Thread starter OKLAHOMAN
- Start date
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southernclay
Member
Here is Penn State's
http://www.pennstateind.com/library/PKM-BUSH3.pdf
They say outside diameter of .330". CSUSA has .335"
Jr II series would be good to have too, thanks and congrats to both of you
I'll be looking to buy a few set's. I was hoping to have a few TBC pens done by now. But I guess things done always work as we hope.
OKLAHOMAN
Member
Order placed
The order is placed and we should have stock in 30 to 45 days, it looks like you want 60 degree recesses instead of a .248 hole through the bushing and that is what we will do. You speak we listen:biggrin:
The order is placed and we should have stock in 30 to 45 days, it looks like you want 60 degree recesses instead of a .248 hole through the bushing and that is what we will do. You speak we listen:biggrin:
edstreet
Member
Weather providing and the like ...
You just gotta move farther north Ed.
edstreet
Member
I am 110 miles south of Atlanta and right now they are under nasty while it's just a cold rain going on here. However that's 1-2 zones away as well...
PenMan1
Member
I'll buy them either way. The ones I got from JohnnyCNC years ago are getting tired.
I would prefer them with 7mm holes, but I can drill holes in the few that I use that way. GOOD JOB! It's about time we have these back in the market place!
I would prefer them with 7mm holes, but I can drill holes in the few that I use that way. GOOD JOB! It's about time we have these back in the market place!
lorbay
Member
Dan Masshardt
Member
He has slowed way down from before but is still making some and some others on request as time allows.
OKLAHOMAN
Member
Lorbay, Johnny has always made terrific bushings but his other activities have slowed his making of them to almost a standstill, what we are trying to do is give a constant supply of TBC bushings. If Johnny was able to do this we would not , but the call for them has been overwhelmingly good to our entering the marketplace with them.
Charlie_W
Member
Constant Laubscher
Member
Charlie_W;1629590 Does this include the Sierra Vista/Wall Street III?[/quote said:
OKLAHOMAN
Member
Skippy, yes the 7MM hole also has a 60 degree recess, and frankly that's the way I would prefer but in the voting it's almost 3 to one with now drill through and just a 60 degree recess so we will do what the majority wants.
It's not clear to me why, I've used both and both work equally well. While the drill through will have a little less gripping area, surely no one is thinking that's going to make a difference in the turning? Or in the amount of pressure needed for a good safe hold by the live center?
OKLAHOMAN
Member
LeRoy I totally agree that the through hole would not effect the turning as there is enough meat that the 60 degree recess is more than actually needed, but as been often said "When in Rome do as the Romans ask us to do" or something like that. :wink:
BTW as to why I would prefer the through hole, as a supplier I have customers that want accuracy in a better bushing that most imported bushing but do not TBC so this gives them the best of two worlds and when or if they do decide to try TBC they are tooled up with the proper bushings.
edstreet
Member
The 'hole' removes approximately HALF the weight of the bushing. Also removes at least half, possibly more, structure strength of the bushing from outside forces. The 'hole' also removes the surface contact to the live center and dead center.
For some materials this may be workable but I can see a need for heftier work loads there could be problems.
Constant Laubscher
Member
Bushings with 60 degree and no thru hole & one with a thru hole.
TBC ( Turn Between Centers ) & MTBC ( Mandrel & Turn Between Centers)
Material is 303 Stainless steel
Bushing type is for the Executive Pen from PSI
60 Degree with No thru hole
Weight = 12.04 g
60 degree Surface area = .046 square inches
60 Degree with Thru Hole
Weight = 7.65 g
60 Degree surface area = .046 square inches
I agree less material will make a part weaker but for pen turning it would be insignificant.
There are many ways around the problem using different materials like tool steel or other, heat treatment of the materials but it all add cost to the product in many ways. Probably more than double or triple, but yes it can be done if the demand is there and people are willing to pay a higher price.
BTW All bushings using mandrels has holes thru them and that is what has been used for years. TBC & MTBC is an improvement on that with better quality materials and tighter tolerances.
TBC ( Turn Between Centers ) & MTBC ( Mandrel & Turn Between Centers)
Material is 303 Stainless steel
Bushing type is for the Executive Pen from PSI
60 Degree with No thru hole
Weight = 12.04 g
60 degree Surface area = .046 square inches
60 Degree with Thru Hole
Weight = 7.65 g
60 Degree surface area = .046 square inches
I agree less material will make a part weaker but for pen turning it would be insignificant.
There are many ways around the problem using different materials like tool steel or other, heat treatment of the materials but it all add cost to the product in many ways. Probably more than double or triple, but yes it can be done if the demand is there and people are willing to pay a higher price.
BTW All bushings using mandrels has holes thru them and that is what has been used for years. TBC & MTBC is an improvement on that with better quality materials and tighter tolerances.
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kovalcik
Member
Maybe the poll asked the wrong question. Maybe a better question is "Would you object to making the bushings MTBC?" Could be many TBC turners just don't envision ever using a mandrel again so voted with that in mind hence the 2+ to 1 split.
From Constant's pictures it does not seem that the bearing surface is a big issue either way due to the relief hole. As for the "structure strength" of the bushing, I don't think I would want to use a pen made from material that was heavy enough to cause a structural bushing failure!
//Geek alert
As far as the weight difference, that is pretty much a wash also since you are removing the mass from the center of the bushing. The mass at the center contributes much less to the angular momentum than the mass at the outer edge, so the net effect of the weight loss is much less thatn the actual weight difference. (Solving the integral to prove this is left as an exercise for the student.)
end Geek alert//
For full disclosure, I voted for the MTBC choice. I like to keep my options open. If most of the 45 voters would still buy the MTBC version plus you pick up the other 19 voters (using the current poll numbers) seems that would be a better solution for everybody.
From Constant's pictures it does not seem that the bearing surface is a big issue either way due to the relief hole. As for the "structure strength" of the bushing, I don't think I would want to use a pen made from material that was heavy enough to cause a structural bushing failure!
//Geek alert
As far as the weight difference, that is pretty much a wash also since you are removing the mass from the center of the bushing. The mass at the center contributes much less to the angular momentum than the mass at the outer edge, so the net effect of the weight loss is much less thatn the actual weight difference. (Solving the integral to prove this is left as an exercise for the student.)
end Geek alert//
For full disclosure, I voted for the MTBC choice. I like to keep my options open. If most of the 45 voters would still buy the MTBC version plus you pick up the other 19 voters (using the current poll numbers) seems that would be a better solution for everybody.
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OKLAHOMAN
Member
Ed, point well taken if we were talking about a bolt on a back hoe stress factor but we're talking about the force it would take to bend, distort, or otherwise harm a bushing on a lathe making a pen blank round. These are made from 303/316 aircraft approved stainless steel. Sometimes we over think quality and strength in a product which can be good some times but not in this case. We can agree to disagree. See this post to also see that there is no difference in contact on the 60 Degree thru drilled and non drilled thru.
TBC Bushings are comming - Page 6 - International Association of Penturners
Dan Masshardt
Member
What does the hole gain though for those turning between center?
The extra weight and grip surface may or may not make a real difference but I don't see a thing to be gained by having the hole through for those turning between centers
Personally I like overkill
beefier the better!
Dan Masshardt
Member
That is good reasoning It would make sense to offer those bushings especially for the kits you sell
Constant Laubscher
Member
What does the hole gain though for those turning between center?
The extra weight and grip surface may or may not make a real difference but I don't see a thing to be gained by having the hole through for those turning between centers
Personally I like overkill
That way we can serve both the people who want to use a mandrel and the once who just turn between centers.
Kill two birds with one stone:biggrin:
Dan Masshardt
Member
I agree The question is, will mandrel turners who already have bushings buy these to continue mandrel turning? I'll guess the number is much less than those who want them for strictly tbc
It seems that first time bushing buyers would be the big target for the dual purpose bushings
These are all just hunches though I'm likely mistaken
All I know for sure is that I have no need for a hole through Yes, If I need one and the dual purpose is what's available, I would buy it
Roy -since you sell the Jr. Series, maybe run some of both for this series and see what sales do? That would give you an economic survey rather than just opinions without $$
OKLAHOMAN
Member
Tom, great point on how I phrased the poll. You very well might be right as the numbers are now 70-30 where yesterday they were 40-11.
OKLAHOMAN
Member
You have the right to change your mind.
Since the debate came up to the reasons for and against a thru hole, I'll ask this to the proponents of no thru hole. As we most agree that there is no real lost of strength in pen turning and the contact area on the 60 degree surface is the same would you object to the thru hole as this would give those that are looking for TBC and those that are mandrel turners but want a better bushing than what is supplied by our overseas manufactures. When I made the poll I should have had a third listing saying would you object to a bushing that suits both needs.
Since the debate came up to the reasons for and against a thru hole, I'll ask this to the proponents of no thru hole. As we most agree that there is no real lost of strength in pen turning and the contact area on the 60 degree surface is the same would you object to the thru hole as this would give those that are looking for TBC and those that are mandrel turners but want a better bushing than what is supplied by our overseas manufactures. When I made the poll I should have had a third listing saying would you object to a bushing that suits both needs.
kovalcik
Member
I like the MTBC option for a couple of reasons. Sometimes I just want to be able to see both barrels of a pen while turning to shape. Sometimes I have a pen on each lathe so one is TBC and the other is on a mandrel. Sometimes I am just lazy and decide to leave the mandrel set up. I personally do not see much difference between mandrel or TBC turning except in the quality of the bushings. My main reason to get the TBC bushings is for bushings with tighter tolerances than the standard imports whether I use them on a mandrel or between centers.
I think what it should come down to is that if the TBC only turners are not adversely affected by a mandrel hole and you could sell 30% to 50% more bushing sets by adding the hole, why wouldn't you? If it makes no difference quality wise, it makes more sense to provide a single, flexible solution than to ignore a portion of the market or to provide two redundant solutions.
I think what it should come down to is that if the TBC only turners are not adversely affected by a mandrel hole and you could sell 30% to 50% more bushing sets by adding the hole, why wouldn't you? If it makes no difference quality wise, it makes more sense to provide a single, flexible solution than to ignore a portion of the market or to provide two redundant solutions.
Jim15
Member
I change my vote from no hole to the ones that have a hole. I really had no reason other than the ones I have have no hole. When I think about it it makes sense to make them with the hole to accommodate both types of turners.
Donovan
Member
I turn up my own bushings for TBC. So not having a hole does not bother me at all
Donovan
Donovan
Dan Masshardt
Member
1. I already have most of the bushings I need for the time being - I will prob still buy a couple sets.
2. In the interest of others, I will still buy with the hole, but I prefer no hole and would still vote that way for what I like most.
For comparison, here are Jr. Series bushings. One is Constants, the other Johnny's.
Interestingly, with the hole, the bushing contacts the center higher with the hole. Hopefully the picture show how much and where is the contact area. (This is not to prove any point, just an FYI.
2. In the interest of others, I will still buy with the hole, but I prefer no hole and would still vote that way for what I like most.
For comparison, here are Jr. Series bushings. One is Constants, the other Johnny's.
Interestingly, with the hole, the bushing contacts the center higher with the hole. Hopefully the picture show how much and where is the contact area. (This is not to prove any point, just an FYI.
Attachments
Of course that is exactly what one would expect the point of the live center has a hole to go into and it will go in farther than if you have just a tiny point hole as John Goodin's do.
edstreet
Member
Always been 70% + in favor of no holes, always will be regardless.
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OKLAHOMAN
Member
Actually Ed it makes no big difference as the 30% who voted a thru hole did for a reason, and the 70% who voted no thru hole did it because that's what they are used to and the way I framed the poll left them no other choice. As a vendor I think 99% of the voters who voted no thru hole would still buy them and all 30% who voted thru hole would also buy them, so the sound business decision would be to accommodate all at this point. We are going to keep the cost down as much as possible so making one style at this time would accommodate the most customers and help us have the lowest final price available. As always appreciate your input.
Dale Allen
Member
Well of course it will sit higher, or farther into, the 60 degree center. The hole is larger. It has nothing to do with the taper of the hole.
If you look closely at the one from John Goodin, it is drilled with a center bit. That is to make sure the point of the center never bottoms out.
I suspect that the ones made with the mandrel hole were purposely drilled deeper to give the extra contact surface.
You are right. The live center is a cone - going into a slightly less than 7mm hole with a taper machined at the entrance, the live center has to go in until the diameter of the cone is equal to the diameter of the hole which should be when the cone contacts the tapered edge of the hole.
thewishman
Member
44% lighter means 44% cheaper - right?:wink:
Why not just start a new poll and phrase it the way you want?
I'd be willing to vote again.
Why not just start a new poll and phrase it the way you want?
I'd be willing to vote again.
mywoodshopca
Member
Well, I have both constants and johnny's bushings. I do prefer them with the hole for the mandrel.
There is PLENTY of contact left on the 60s that the tip wouldn't matter that much IMO. I never read all the way through the threads past the first 1.5 pages, But I would love to upgrade all my bushings to 60s with a mandrel hole for some kits that I still want to turn the tubes together.
There is PLENTY of contact left on the 60s that the tip wouldn't matter that much IMO. I never read all the way through the threads past the first 1.5 pages, But I would love to upgrade all my bushings to 60s with a mandrel hole for some kits that I still want to turn the tubes together.
edstreet
Member
Sorry, dont get offended but you are going with the hole regardless of what the 70% majority voted for? What was the point of having the vote in the first place other than a marketing ploy? Did I read that right?
Also one last question on this, been bugging me for a very long time now. What end user advantage is there to having a TBC bushing with a hole in the middle of it? I can think of no advantages at all from the end users standpoint. The only advantage I can think of is perhaps to push one product to multiple groups while skimping on machine time to increase profits.
OKLAHOMAN
Member
Chris, I wish I could but the rules forbid me from doing another pole for a month and only 6 in a year.
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LeeR
Member
My head is spinning over what actually is being proposed.
If the contact area is going to be the same for TBC and MTBC, then I don't care if you do MTBC bushings. In fact, I'd prefer it, since I now use a collet check with pen mandrel, and would do so for some pens, and acquire new bushings over time. My thought originally was that MTBC bushings would have less contact area.
BTW -- if anyone does not have a dead center, Amazon has carbide-tipped ones (Grizzly product, but stocked at Amazon). I just got one. Drilled out a set of bushings with a center drill and will try it out on my next pen.
If the contact area is going to be the same for TBC and MTBC, then I don't care if you do MTBC bushings. In fact, I'd prefer it, since I now use a collet check with pen mandrel, and would do so for some pens, and acquire new bushings over time. My thought originally was that MTBC bushings would have less contact area.
BTW -- if anyone does not have a dead center, Amazon has carbide-tipped ones (Grizzly product, but stocked at Amazon). I just got one. Drilled out a set of bushings with a center drill and will try it out on my next pen.