Sliding tubes

[cryptolo]

When I square up the ends of my blanks with the tubes inside this happens quite a lot.
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For some reason I cannot get my holes drilled perfectly straight threw the blanks so when I put them in a small vice and back on the drill press with the tubes inside they are slightly catywompus which leads to friction from stress caused by the uneven hold and the tubes are pushed through the blanks. Is it my krukid holes as described above thats leading to my tubes being pushed out or is it my epoxy? I currently use this epoxy PSI Mid-Cure Epoxy at Penn State Industries


Thanks!

EDIT: I should note my epoxy is at least 4 years old... is that past its shelf life?

 

[Edgar]

In general, the holes don't have to be straight. That's the purpose of the squaring mills - to make sure the ends are perpendicular to the tubes. It's only when you're dealing with very small (say 1/2" square) blanks or working with a blank with a particular pattern (like the pool cue blanks shown in another thread) that you need to be careful about drilling a straight hole.

I think your problem is either inadequate glue coverage or that you didn't let it fully cure. The way I do it is to apply a liberal amount of glue on the tube then slide it in with a back & forth and twisting motion to be sure the glue fully covers the tube and the inside of the blank. I haven't had a tube release problem since I started doing that. I use medium or thick CA (depending on humidity that day) and I've long stopped sanding the tubes. You just need to develop your own technique that works for you, but full coverage & curing is a must.

The other thing that can cause this is if the shaft of the mill doesn't turn freely inside the tube. Make sure that you don't have any glue inside the tube before trimming the blank.

EDIT: I don't use epoxy at all, but 4 years seems rather old to me. I'd get some fresh stuff.

 

[RKB]

Feel your pain.:frown: I have had this happen to me and I found that it was glue in the tube and my trimmer kinda siezed up inside the tube and spun them out of the blank. I started plugging the tube ends with wax to keep the glue out of the tube. Hope this helps. :biggrin:
Rod

 

[cryptolo]

Okay neat, that is what I was sort of hoping to hear. I will pick up some new adhesive to try out. My epoxy says full strength in 3 hours but I wait around 12 each time and its always inside around 70 degrees.
To try and get around this problem I have done nearly everything except buy new glue to use. I use fine sand paper to clean my squaring mill before each blank to get rid of any debris and have even tried applying some wd-40 to it to keep smooth contact inside the tube.
Like you said I may have some epoxy sitting inside the tubes which would cause them to be pushed out from friction which I will look for next time. If that is the case what would be your recommended way to get rid of epoxy inside the tubes?

Thanks again!!

EDIT: RKB, that absolutely helps I was wondering how I could keep epoxy from sneaking inside the tubes during the glue up process

 

[Edgar]

Lots of folks plug the tube ends & that's a good technique. I just wipe the ends of the tubes with a paper towel after inserting the tubes then check them before milling. If I see any glue, I use the end of the mill or a rat file to clean it off.

The other thing that helps is that I don't put much glue near the ends of the tube. I let the in-out & twisting motion make sure there is coverage there, but thT helps to keep glue from flowing into the tubes. Wiping excess glue off the ends also helps to seal the end of the blank & get full tube coverage at the end.

Lots of ways to do it - just keep experimenting until you find a consistent method that you like.

 

[GaryMGg]

Try using something else to learn if you can push the tubes out.
Maybe a burnisher, or a 1/4" (or 17/64") drill bit end--anything that's real snug.
If so, either your glue is no good OR your ratio is wrong.
If the tubes are moving after setting for 12 hours, the glue may never set.

 

[low_48]

Epoxy likes a little thickness to the glue joint to get it's strength. If the tube is too tight in the hole, you will wipe all the epoxy off and not get a good bond. I don't see any glue residue on the tubes, but there isn't much showing. The tube should easily slide in when using epoxy, and I prefer to sand to clean up the blanks. Much easier than the mill.

 

[butchf18a]

Some good advice so won't duplicate those things.

I use Locktite 5-min epoxy. I scuff up my tube and make certain they will slide cleanly all the way through before applying any adhesive. Glue inside blank to coat then tube, insert with twisting motion.

I know it says fully cured in 3 hours, however heat generated from barrel trimmer can cause epoxy to soften and fail. I generally drill and glue in tubes one day, wait overnight befor trimming and turning. An excellent way to reduce friction is to spray small amount of Pam cooking spray on shaft of trimmer. Yep that stuff your wife likely has in her pantry.

Jmoicbw-bidi

 

[darrin1200]

[QUOTE
For some reason I cannot get my holes drilled perfectly straight threw the blanks so when I put them in a small vice and back on the drill press with the tubes inside they are slightly catywompus which leads to friction from stress[/QUOTE]

I think puting the blanks back in the vice may be part of your problem. The idea of the end mill is to use the shaft of the mill to align the tube so that the cutter is square to the end. If the end mill is locked in the drill press, and the blank is locked in the vice neither one has any movement to allow alignment. Even if it is only off a smidge, it will cause the brass tube to seize on the shaft and the weekest point will give.

When i was using an end mill on the drill press, i would hold the blank lightly in a quick grip clamp. The clamp is only there to give me mechanical advantage to keep the blank from spining. Because it is held lightly, the blank can shift off vertical to come into alignment with the end mill.

This is one of the reasons i bought the offset lathe sanding jig from our own rherrell. It makes the squareing up easy.

 

[Tim'sTurnings]

You have had a lot of possible answers to your problem with your tubes coming out of your blanks. I believe it all comes down to the glue. The tube should not come out if it is glued correctly. I think that is your main problem.
Tim.

 

[SteveG]

Often times, when something goes wrong, it is a combination of problems ganging up on you. The following item might have added to the cause(s) behind the problem:

The pics look like 7mm tubes. I no longer use a pen mill, but when I did, I found that the fit of the cutting surfaces of the mill to the 7mm pilot shaft was not tight. The small gap was exactly where the tube is located when milling. So if you cut into the tube at all, the mill was actually grabbing the tube in that gap, which would tend to spin the tube and push it. (This does not happen with larger tubes since the pilot shaft was larger than the 7mm part of the mill shaft, thus moving the cutting action away from where this small gap existed.) It is possible this contributed to the issue. It will show up as a non-clean cut surface on the end of the tube(7mm) after you have used the mill. For me, I have long since avoided pen mill issues by not using a pen mill.

 

[cryptolo]

I think puting the blanks back in the vice may be part of your problem. The idea of the end mill is to use the shaft of the mill to align the tube so that the cutter is square to the end. If the end mill is locked in the drill press, and the blank is locked in the vice neither one has any movement to allow alignment. Even if it is only off a smidge, it will cause the brass tube to seize on the shaft and the weekest point will give.

When i was using an end mill on the drill press, i would hold the blank lightly in a quick grip clamp. The clamp is only there to give me mechanical advantage to keep the blank from spining. Because it is held lightly, the blank can shift off vertical to come into alignment with the end mill.

This is one of the reasons i bought the offset lathe sanding jig from our own rherrell. It makes the squareing up easy.

that is exactly what is happening, since the mill and tube are not aligned they cause extra stress/pressure which pushes the tube out. i tried the exact method you described with a loose clamp and it helped. thanks!!

thanks to everyone for all the fast and helpful answers

 

[low_48]

That misalignment in the drill press may be pushing them out, but a quality epoxy joint would require you to drill the brass out to get it to release. I still think your epoxy work is not up to par.

 

[wyone]

I still use a pen mill, although I am putting together an order for some tools, including a sanding jig from Rherrel after the holidays. I also use a pen vice, but I do not bolt it down, or anything, I just hold it lightly. I have had no issues when using it this way.

 

[butchf18a]

Vise not vice

 

[wyone]

LOL yes.. thanks for the correction... WHOLE different meaning...

 

[ldb2000]

Everyone is on the right track but the wrong answer . The problem you are having is from heat , when your mill shaft rubs inside the tube you generate heat from friction and the heat softens the glue allowing the tube to be pushed out . Also make sure that the inside of the tube is free of glue and burrs which can also cause friction generated heat .
If your not using a pen drilling vise it will be very hard to align the blank to the shaft so best bet is to hold the blank against the mill with a pair of vise grips preventing the blank from being misaligned , NEVER hold the blank by hand , always use pliers or vise grips .
This is a tip , the heat that is causing your problem can also work for you . If you ever get a tube stuck halfway in the blank when gluing them in with ca , heat the tube a little by holding a soldering iron in the tube , don't touch the walls of the tube , to soften the glue and you can remove the tube without damaging the blank or tube.

 

[monophoto]

To try and get around this problem I have done nearly everything except buy new glue to use. I use fine sand paper to clean my squaring mill before each blank to get rid of any debris and have even tried applying some wd-40 to it to keep smooth contact inside the tube.

Your process seems to focus on the pen mill. That's fine, but as Ed said, your problem is far more likely to be how you glue the tube into the hole. Some suggestions:
1. Scuff the brass tube with medium--coarse (eg, 100g) sandpaper before applying the glue. Glue will readily adhere to the wooden blank, but the bond to the brass will be less secure. But if the glue adhering to the wood cures in the tiny scratches left in the brass by the sandpaper, the grip on the tube will be far stronger.
2. I apply a continuous bead of glue with a toothpick or coffee stirrer in a line along the length of the tube starting about 1/4" from the end that goes into the tube. Then, I twist the tube as I slowly insert it into the hole, pushing it most of the way in, then backing it out a bit before pushing it to its final depth to smear the glue over entire surface of the tube.
3. I tend to apply more glue than necessary - you can't really use TOO MUCH glue, but it's easy to starve the joint.
4. Yes, there is an issue with glue getting inside the tube. You don't need to plug the tube although that is a good solution. Some people use Play-Doh to seal the end of the tube; some of the older books suggest poking the tube into a raw potato to cut a plug to block the end of the tube. I have found that leaving that 1/4" gap in the bead of glue at the end of the tube really helps minimize the amount of glue that is pushed ahead of the tube and bleeds back inside. Frankly, getting glue inside the tube is more of a problem if you are using epoxy because it is harder to remove after it cures. I use polyurethane glue which is relatively easy to remove.

 

[bgio13]

I have been using the same epoxy for the last four years and have never had a problem with tubes loosening up. As others have said heat could be the main issue, and one possible cure has not been mentioned. From the picture, the blank on the right looks like you removed a lot of material with the pen mill to square up the blank. I think cutting your blanks a little closer to the size of the tube will cut down on the time the mill is spinning in the blank, thus not heating up the blank as much. Hope this helps,

Bill

 

[ClutchCargo]

....heat could be the main issue, and one possible cure has not been mentioned. From the picture, the blank on the right looks like you removed a lot of material with the pen mill to square up the blank. I think cutting your blanks a little closer to the size of the tube will cut down on the time the mill is spinning in the blank, thus not heating up the blank as much.

I too have had occasional issues trimming blanks made of various materials and/or with using certain types of adhesives to glue in brass tubes when using a pen mill to square up the blank. So one of the ways I cut down on the heat issue and maintain perfect perpendicularity at the same time when trimming blanks to the correct length after gluing in the tubes is to replace my table saw blade with a sanding disk and use the table saw's miter gauge set at a perfect 90-degrees to the disk as my fence (those who have dedicated sanding machines with a 90-degree fence are already set). I can then move the pen blank along the miter gauge and just barely touch the end of the blank to the rotating sanding disk until I see the shine of the brass tube. This incrementally trims up the end without causing any heat to the remaining blank or tube. I've found this technique to be most helpful when truing up very dense segmented blanks or blanks made from various pieces of hardwood that are glued together and then cut on a 15-degree bias. Once the blank is trimmed to length, a reaming tool can make quick work of cleaning out the inside of the tube without the pen mill causing additional heat or vibration. In essence, instead of using the pen mill and reaming tool as a combination device where the spinning reaming tool inside the tube is causing heat buildup the entire time the mill is squaring the end, my sanding disk takes care of squaring the blank without causing heat buildup inside the tube, and then the reaming tool cleans out any glue in the tube without vibration from the pen mill.