TBC Vendor quality differences.

[edstreet]

these are bushings I picked up rather recently and please dont ask vendor as this is not about vendor but about quality.

a zoomed in view, actually size and no adjustments on either.

This is as they were received. Both are new and unused.

This one is the end selection that matches up with the live/dead center.

Here we see one has a deep valley at the end of the brass tube, what happens is that tube *will* curl into this area with enough force applied. Thus wedging the bushing in place. More apt to happen when there is burrs and the like on the edge of the tube.

Here is a more zoomed in view showing the 2 ledges.

As for the 'spots' some have said oil spots but they are not. Others have said tool impact marks but that to I think is incorrect.
Honestly I am not sure what they are but they are on all 4 of them.
If someone wants to enlighten me then I'm all ear's

Also worth note is the 'slop' I measured was a wide range, one being very close to the tube size and the other over 2x that.

 

[HamTurns]

I just ordered and received my first set of TBC bushings and encountered quality issues as well.

I had to take a file to the bushings just to get them to slide onto the tubes I had because of burrs.

The odd thing was that there was an extra set of bushings in the box, one set clean as a whistle and the other set had the quality issues.

I'm going to inspect them tonight for the "valley". That may answer why I had a heck of a time pulling the completed pen barrel off the bushing.

Happy turning
Tom

 

[Dan Masshardt]

Ed,

I have several bushing sets from the only two vendors that I'm aware exist. I don't have any that are as rough looking as that one.

I wonder if it is an exception?

 

[TBCbushings]

WOW! Those are bad...Mine are 100000% better!

 

[TBCbushings]

Those marks look like they are from the casting of the metal...Impurities is my guess

 

[Justturnin]

Dang Ed, I know you like dealing with high end stuff but Damascus bushings???? Come on now :biggrin:

Those sure do look pretty rough. Did you reach out to the vendor? I wonder if this vendor makes them or has them made?

 

[GoodTurns]

... Damascus bushings???? Come on now :biggrin:

exactly what I thought!

Never seen any like that,,,definitely contact the vendor.

 

[brownsfn2]

Same here. Mine were shiny new and almost too pretty to use. They fit so well that I can't have any burr or glue residue in the tube or they will not insert. I really like them. Since you did not mention a vendor I won't either. You can contact me to find out who though.

 

[edstreet]

I just ordered and received my first set of TBC bushings and encountered quality issues as well.

I had to take a file to the bushings just to get them to slide onto the tubes I had because of burrs.

The odd thing was that there was an extra set of bushings in the box, one set clean as a whistle and the other set had the quality issues.

I'm going to inspect them tonight for the "valley". That may answer why I had a heck of a time pulling the completed pen barrel off the bushing.

Happy turning
Tom

First off let me clear something up here.

Burr's on the brass tube *MUST* be cleaned or you *WILL* have sticking tubes, cracking blanks and the like. They cause nasty problems so remove them from the tubes and don't touch the bushings.

Those marks look like they are from the casting of the metal...Impurities is my guess

Did not think about casting. If it was slag we should be seeing things like impurities, bubbles and the like in there.

Ed,

I have several bushing sets from the only two vendors that I'm aware exist. I don't have any that are as rough looking as that one.

I wonder if it is an exception?

Possibly it is an exception. Worth noting is the tooling marks. There is a very distinct difference between the two which indicates how it was machined. On one set you can see little fine scrape marks that are uniform, the other set you can see the same size marks but every so often it was a rough patch like the machine was having some problems, that's just a guess tho. Even with the spots removed there is still tooling problems going on.

As for contacting about replacements that was never a thought to be honest.

 

[Russianwolf]

first observation. One is cut from bar stock (solid rod) and the other from tube stock. That's why you are seeing a difference in the head/tailstock support area. One being drilled with a center bit and the other is just being beveled.

I tend to agree that the spots are likely from the smelting of the metal. Maybe not impurities per se, but maybe slightly different alloys got mixed in. The slightly different melting points could cause that effect. Most likely the foundry would sell that stock at a reduced price comparatively which fits with the vendor using tube stock as well.

 

[Dan Masshardt]

Why would contacting the vendor not be a thought? They should have checked it going out , sure, but they should probably be given the opportunity to explain and replace. I know I would if I sold them.

 

[rd_ab_penman]

This should be no surprise to anyone and this is why I don't use bushings.

Les

 

[Dan Masshardt]

This should be no surprise to anyone and this is why I don't use bushings. Les

Because there is an issue with one once in a while? I guess you can't use pen kits either then. There as just as many occasional problems there.

(That wasn't intended to be snarky). I'm sure there are good reasons to not use bushings - save money, exact measurements each time - but I don't see how an issue with a bushing set in the midst if hundreds of good ones would be a good reason.

 

[Constant Laubscher]

None of those are bushings made by Lazerlinez just to put that in the clear, I always put a chamfer on the Larger OD of the bushings and a radius on the small OD. The surface finish on our bushings are at least a Ra20 or better.
( Ra is the arithmetic average of the roughness profile )
We do have the hole for a mandrel. "MTBC" Bushing

 

[raar25]

Folks the spots are probably water spots from the tumbler used for deburring. These are most likely not as cast although they could be bar surface, most likely they are machined all over by either on a screw machine or multi spindle cnc lathe. Depending on the tools and machine slop along with speeds and feeds the different surfaces result.

Was there a price difference?

 

[HamTurns]

II had to take a file to the bushings just to get them to slide onto the tubes I had because of burrs.

First off let me clear something up here.

Burr's on the brass tube *MUST* be cleaned or you *WILL* have sticking tubes, cracking blanks and the like. They cause nasty problems so remove them from the tubes and don't touch the bushings.

Hi Ed - I should have been more clear, I had removed the burrs from the pen tube with a chamfer and deburring tool as I always do.

The burrs I'm referring to were on TBC bushings, and until I removed them they would not go into the freshly de-burred pen tubes.

After I filed the burrs off of the new TBC bushings they fit into the pen tubes.

 

[Dale Allen]

Ed, how does this one look?
And I didn't even try hard to make it pretty!:biggrin:

 

[Curly]

The "spots" are because there was a contaminate of some kind, possibly cutting oil, on the surfaces when the parts were etched for cleaning or de-burring. The contaminate masked the part from the acid so the surrounding surfaces are lower.

 

[edstreet]

Hmm bar stock vs tube. I am not sure if you could get tubes where the wall thickness would be that over a bushing. I know they make larger diameter tubes with wall thicknesses that an over but not this small.

The head/tail support area is showing the 2 vendor's approach to the problem. One we have a reduced surface area and a heavy ridge which suprisingly no one has mentioned alignment issues from that. I am not sure if it could/would.

Ed, how does this one look?
And I didn't even try hard to make it pretty!:biggrin:

Good so far. For the purpose of my post here I was looking at more detailed and quality value rather than pretty. One post I did years ago to the CMP was about refinishing products where I did some epic heavy contrast b&w shots of before/after to show how the wood reacted to being treated.

The "spots" are because there was a contaminate of some kind, possibly cutting oil, on the surfaces when the parts were etched for cleaning or de-burring. The contaminate masked the part from the acid so the surrounding surfaces are lower.

Ah that would make sense. Never thought about etching as I was looking elsewhere and tried to ignore the obvious issue.

Hi Ed - I should have been more clear, I had removed the burrs from the pen tube with a chamfer and deburring tool as I always do.

The burrs I'm referring to were on TBC bushings, and until I removed them they would not go into the freshly de-burred pen tubes.

After I filed the burrs off of the new TBC bushings they fit into the pen tubes.

OK my bad, I was somehow thinking that you were cutting the bushings because of burrs on the brass tube and that was a face palm, sorry about that.

Why would contacting the vendor not be a thought? They should have checked it going out , sure, but they should probably be given the opportunity to explain and replace. I know I would if I sold them.

Well yes they should have checked things going out that is true. It was never a thought to contact them on the bushing as I wanted to use it, along with others, and compare different areas. Often times there is a great deal of educational value in projects like this.

None of those are bushings made by Lazerlinez just to put that in the clear, I always put a chamfer on the Larger OD of the bushings and a radius on the small OD. The surface finish on our bushings are at least a Ra20 or better.
( Ra is the arithmetic average of the roughness profile )
We do have the hole for a mandrel. "MTBC" Bushing

Why even go there? It does not matter who made them to be honest. Nor price difference or price paid (as some have ask already) The point of this topic was to not point fingers and playing the blame game that gets you no where very fast. The point was to discuss quality. What design layouts and machining practices is done to yield that of quality and how that affects turners.

The second thing was thank you for bringing up Ra20 as I am guessing that many here are not aware of RMS or Ra. For those who do not know Ra20 is around 200 grit surface (ra25 is 180 grit and ra18 is 240 grit)

The chamfer mention was good so would you mind telling us what benefits that gives the end user?

 

[rherrell]

Also worth note is the 'slop' I measured was a wide range, one being very close to the tube size and the other over 2x that.

This is the only thing I would be worried about, how they "look" is irrelevant. I make my own and they look terrible....but they fit!:biggrin:

 

[joefyffe]

xxx

Ed,

I have several bushing sets from the only two vendors that I'm aware exist. I don't have any that are as rough looking as that one.

I wonder if it is an exception?

 

[joefyffe]

I have never had an issue such as this from Johnny CNC!

 

[edstreet]

Also worth note is the 'slop' I measured was a wide range, one being very close to the tube size and the other over 2x that.

This is the only thing I would be worried about, how they "look" is irrelevant. I make my own and they look terrible....but they fit!:biggrin:

Honestly I am glad someone brought this up. Looks is not everything but function is job #1 here. Things like the groove that I pointed out and the center contact area is very important.

 

[Smitty37]

Ed,

I have several bushing sets from the only two vendors that I'm aware exist. I don't have any that are as rough looking as that one.

I wonder if it is an exception?

Dan while we generally only know two and I have bushings from both as well, and they are great - there are others.

While it isn't well known our normal bushing manufacturers can, and I'm sure will if you ask, make TBC bushings. I could start offering them in a heartbeat all I'd have to do is send them a sample or a dimensional drawing of what I want. - Personally I think they'll start showing up in catalogs sooner or later...when the big guys decide there is enough of a market for them.

 

[edstreet]

Dan while we generally only know two and I have bushings from both as well, and they are great - there are others.

While it isn't well known our normal bushing manufacturers can, and I'm sure will if you ask, make TBC bushings I could start offering them in a heartbeat all I'd have to do is send them a sample or a dimensional drawing of what I want. - Personally I think they'll start showing up in catalogs sooner or later...when the big guys decide there is enough of a market for them.

While it is indeed a good thought that there will be more options down the road I hate to be a wet blanket when I say that I think many really does not know what makes a good bushing. If these sources you speak of are putting out factory style bushings now then I seriously doubt they could ever do any quality bushings of any form, be it for mandrels, TBC or other.

 

[Smitty37]

Dan while we generally only know two and I have bushings from both as well, and they are great - there are others.

While it isn't well known our normal bushing manufacturers can, and I'm sure will if you ask, make TBC bushings I could start offering them in a heartbeat all I'd have to do is send them a sample or a dimensional drawing of what I want. - Personally I think they'll start showing up in catalogs sooner or later...when the big guys decide there is enough of a market for them.

While it is indeed a good thought that there will be more options down the road I hate to be a wet blanket when I say that I think many really does not know what makes a good bushing. If these sources you speak of are putting out factory style bushings now then I seriously doubt they could ever do any quality bushings of any form, be it for mandrels, TBC or other.[/quote]

Well, since they can use the same machines, same stock and same specs as anyone else - I would guess that they can turn out very high quality if they need to.

What we get in bushings from the 'factory' guys now are pretty low priced and made with fairly loose tolerances and inspection criteria . They are willing and able to tighten both if we are willing to pay for it.

 

[Ed McDonnell]

Honestly I am glad someone brought this up. Looks is not everything but function is job #1 here. Things like the groove that I pointed out and the center contact area is very important.

My thoughts on the groove:

A smooth finish when turning metal is facilitated by having a small radius on the leading edge of the cutting tool. Unfortunately this means when you come up to a shoulder you will leave a small radius. This small radius will put expanding pressure on the interior of the brass tube as tailstock pressure is applied to the bushings. This risks damaging the blank.

One way of dealing with this is to switch to a tool without a radius to clean up the shoulder area creating a 90 degree angle instead of the radius. Another way is to just increase the depth of cut at the shoulder so that the radius is not an issue. This results in the "groove" that you cited.

Is the groove a problem? You seem to think that it is and I respect that, but I find myself wondering the following. If you compress the blank enough with tailstock pressure so that the brass tube is deformed into the groove, won't you also be compressing the material that the blank is made out of. Maybe wood is more tolerant of over compression, but I am pretty certain that PR will crack long before the brass deforms into that groove.

I end up with a groove on all the bushnings and jigs I make for myself because it's easier that switching tools to cut 90 degrees at the shoulder. I've never had a problem with tube deformation. I'm not saying you haven't, but maybe the groove isn't your problem in those situations. Maybe a little less tailstock pressure might be the answer.

About the 60 degree hole:

It looks to me like the grungy set of bushings were drilled too far with the center drill (hard to really tell from the picture). The 60 degree center won't make contact with the 60 degree bottom of the drilled hole. It will instead ride on the circumference of the hole at the end of the bushing. Is this a problem? Some people turn between centers without using bushings. (As long as you don't apply too much pressure (which would expand the brass at the ends) this technique will work). With the overdrilled bushing, a heavy handed turner may find that they are able to stop the blank in this situation because there won't be much surface area contact between the drive center and the tube. But the alignment should not be affected. While an over drilled bushing can be made to work, I would consider it defective. But that's just my opinion.

Ed (one of the other ones...)

 

[MesquiteMan]

Except that it is not an over drilled bushing. It has a through hole for being able to use it on a mandrel also.

 

[George417]

Also worth note is the 'slop' I measured was a wide range, one being very close to the tube size and the other over 2x that.

This is the only thing I would be worried about, how they "look" is irrelevant. I make my own and they look terrible....but they fit!:biggrin:

I agree with Rick

 

[Ed McDonnell]

Except that it is not an over drilled bushing. It has a through hole for being able to use it on a mandrel also.

It's really hard to tell from the picture that was posted. I see the smaller diameter thru hole down in there, but wasn't referring to that.

Looking at the largest diameter opening at the end of the bushing, it look like the side of the hole run parallel to the OD of the busing for a while and then the 60 degree angle kicks in (leading to the thru hole).

I'm thinking the centers are going to ride on the large diameter at the end (not the rim of the thru hole). Maybe I'm looking at the picture wrong, but this seems to look like what I see when I (rarely :redface::redface::redface go too far with my center drill. Maybe I'm just seeing things wrong though.

Ed

 

[edstreet]

Ahhh yes that is another very good point. The shaft for the mandrel to the outside diameter, how parallel is it.

 

[Dale Allen]

When I make these it is typically because I want a size that I cannot get from Johnny. Also, I often go too small when making them and either toss it or use it later for a smaller size. On some of mine I have to use a pliers to remove it but that's OK cause I know there is no slop!
I have made many that are within a few thousandths of another one.
That is because there are way too many variances in the tubes from one source to another, and possibly between one run and another.
It may say to use a 15/32 bit but the bushings will not work.
I seriously doubt they will be available as mass produced and have the precision I require.
Could be that I am too picky....but I'll take that!:biggrin:

 

[johnnycnc]

Neat photos Ed!
spotted steel. groovy.
a through hole for mandrel defeats the whole point in my book;
Kind of like a corvette with factory tow hooks to pull her out of a mud hole. yokay.
Guess I need to buy a lathe and try making some too.:rotfl:

 

[edstreet]

Honestly I am glad someone brought this up. Looks is not everything but function is job #1 here. Things like the groove that I pointed out and the center contact area is very important.

My thoughts on the groove:

A smooth finish when turning metal is facilitated by having a small radius on the leading edge of the cutting tool. Unfortunately this means when you come up to a shoulder you will leave a small radius. This small radius will put expanding pressure on the interior of the brass tube as tailstock pressure is applied to the bushings. This risks damaging the blank.

One way of dealing with this is to switch to a tool without a radius to clean up the shoulder area creating a 90 degree angle instead of the radius. Another way is to just increase the depth of cut at the shoulder so that the radius is not an issue. This results in the "groove" that you cited.

Is the groove a problem? You seem to think that it is and I respect that, but I find myself wondering the following. If you compress the blank enough with tailstock pressure so that the brass tube is deformed into the groove, won't you also be compressing the material that the blank is made out of. Maybe wood is more tolerant of over compression, but I am pretty certain that PR will crack long before the brass deforms into that groove.

I end up with a groove on all the bushnings and jigs I make for myself because it's easier that switching tools to cut 90 degrees at the shoulder. I've never had a problem with tube deformation. I'm not saying you haven't, but maybe the groove isn't your problem in those situations. Maybe a little less tailstock pressure might be the answer.

About the 60 degree hole:

It looks to me like the grungy set of bushings were drilled too far with the center drill (hard to really tell from the picture). The 60 degree center won't make contact with the 60 degree bottom of the drilled hole. It will instead ride on the circumference of the hole at the end of the bushing. Is this a problem? Some people turn between centers without using bushings. (As long as you don't apply too much pressure (which would expand the brass at the ends) this technique will work). With the overdrilled bushing, a heavy handed turner may find that they are able to stop the blank in this situation because there won't be much surface area contact between the drive center and the tube. But the alignment should not be affected. While an over drilled bushing can be made to work, I would consider it defective. But that's just my opinion.

Ed (one of the other ones...)

On the groove there is actually a big perk to having them. That is if there is any burrs or buildup of anything like glue, shavings etc.. they would just fill that area. I could easily see how a blank could have non-uniform stress on it due to burrs and other irregular pressure causing nasty things to happen. We know it happens on assembly of the press in parts but my current working theory is it also hinders us when turning so the groove is a good thing.

If the insert is long enough the groove should not be a bad thing. If the insert is short then I can see it causing problems as not enough support.

 

[Smitty37]

This is an interesting thread and I think we've all learned something from it, but I have a couple of points that might bear on why we see the variations we see in bushings.

As many here have said - the bushings are Just a guide to get you close, use your caliphers to finish.

Many also say "I always turn a little below the bushing and build back up with CA to get to my final dimension.

Quite a few say "You don't need bushings at all when Turning Between Centers just measure and turn making sure your live center has a 60 degree taper."

While I know bushings can be made precise to a gnat's eyebrow and mass produced with darned high precision (I've seen parts accurate to 4 decimal places to the left of the decimal point) I don't think there is enough of a market to pay the freight for that kind of precision. And as someone mentioned in an earlier post - the tubes and pen kit parts aren't all that precise or consistant either, nor will they be because we wouldn't pay for that kind of precision in kits either.