Bridgeport tech question

[kool55]

I am notching a joint in a 2 inch tube at 45 degrees using a holesaw. Problem is my drill chuck is slipping between the chuck and the shank[at the tapered connection]. Is it because I am side loading the chuck ? THANKS

 

[Atlascycle]

That is probably what your problem is. Are you using a standard store bought arbor for the hole saw? If so the run out in the arbor combined with the side loading is what is doing it, I made a arbor to go in a collet that pilots the threaded hole in the hole saw and holds the cutter on by using SHCS, that works much better, I have used it o hold a 4.5" hole saw and cut .75" plate with it. YMMV

Jason

 

[kool55]

I can see some runout as it spins. I thought maybe a 1 piece r8 chuck would work. I am using a Lenox hole saw with a threaded arbor.

 

[Kevin54]

Why not chuck it up in a collet instead of a drill chuck? Also to tighten your chuck and shank up, turn it upside down and rap it down on the bench driving the shank into it further.

 

[kool55]

I tried to tighten the shank to chuck by banging it upside down. The arbor is hex shaped. I do have a small selection of collets, but no round chucks. I was looking on Ebay and seen a few r8 chucks for cheap. I don't know about the quality though.

 

[-B-]

You need a better arbor and be sure to check speed and feed it is critical on AL. You will also want to true up the saw itself unless it does not matter.

 

[A_Pmech]

Let's hear some more about this setup, maybe with photos.

How is the hole saw cutting? Freely? Chatterville? Snagging?

Speed?

Feed method?

What is the condition of the Jacobs taper in the back of the chuck and on the R8 arbor?

 

[kool55]

I am still having a hard time with pics. However I have a 35'' piece of 2'' tubing clamped in my bridgeport vise with the head tilted to about 45 degrees. I

 

[kool55]

I didn't finish. Anyway I am hand feeding with some chatter using a 2'' lenox holesaw. I made 1 notch before the chucks tapered shank started slipping in the chuck. The chuck shank is ok in the R8 collet.I don't if the tapered end is worn. The chuck is a Supreme Precision 1/2'' straight shank. The holesaw arbor is a hex.

 

[kool55]

OH, I am running the bridgeport thru a VFD at a slow speed.

 

[Kevin54]

I tried to tighten the shank to chuck by banging it upside down. The arbor is hex shaped. I do have a small selection of collets, but no round chucks. I was looking on Ebay and seen a few r8 chucks for cheap. I don't know about the quality though.

Now I'm getting lost. The arbor of the chuck that you are currently using is hex shaped? I think I know what you are talking about but I think what you are calling the chuck may be the collet? Let me ask it this way....the hole saw you are using has a hex shaped shank. Correct? They you are chucking this up in a drill chuck that in turn is in an R8 collet in the Bridgeport. Correct?
If that is the way it is, and the hole saw does not have a very big arbor/shank to it, your stackup is getting a lot of play. This in turn will create problems as you will be sideloading the chuck. For your optimum setup, everything needs to be short as possible and rigid. A drill chuck in a mill should be used just for that purpose....drilling. This put an equal load as everything is straight downward pressue with no sideloading. You need to find a chuck that the holesaw will fit into. Even if it is hex, you could find an R8 collet that is round that it would fit into reasonably well. If it is a setup that you would be using on a continual basis, then I would get an adapter made that is round that would fit into a conventional R8 collet. Pics of your setup would be a huge plus.

Just seen your last response. Try speeding up the saw somewhat and use a little oil on it to keep the aluminum from galling up in the teeth of the saw. You may be running too slow for your feed and it is causing it to grab. I would try around 500 RPM's and a slow feed with a drop or two of oil on the cutter.

 

[A_Pmech]

Kool, here are a couple of thoughts that might be helpful:

Disassemble the Jacob's taper and have a look inside.

If things aren't pristine on either tapered half, that's your problem.

If the taper is fine or only lightly galled you need to properly seat it with a lead mallet. Open the chuck until the jaws have receded into the body. Put the R-8 end down on the hard floor or an anvil, with a piece of Aluminum, Brass, etc between the R-8 and the floor/anvil.

Give the chuck body a couple of solid hits with a lead mallet. Don't be shy, let it know who's boss. At the same time, don't beat the hell out of it.

The above MUST be done on a hard surface. A wooden workbench will absorb the majority of the impact.

Unless the chuck has the smallest Jacob's taper, it should be capable of driving your 2" hole saw if you're careful. While side-loading is an issue due to the reactionary forces acting on the taper, I've never had a Jacob's taper walk out with a hole saw of that size. Not saying it can't happen though!

Speed should be about 80-120 FPM (225 RPM or so) with sulphurized cutting oil. Too slow and the teeth well tend to grab. Too fast and you wear them to nubs.

If that doesn't fix your problem, I'd look for an R-8 arbor with a 5/8" threaded mount. Then, find a 5/8" threaded-back chuck. That WILL solve the problem!

 

[kool55]

Thanks Kevin. You are correct. My hex arbor is mated to the 1/2'' chuck, then to the R8 collet. So the chuck is not to be used for angle applications? I have spent the best part of today looking for a better design arbor that will fit directly to the R8 collet , thus eliminating the drill chuck.

 

[kool55]

OK, A PMECH, I will try again to seat the chuck/arbor. I do have a steel bench[3/4] that I am using.That 5/8 threaded arbor chuck sounds good. I did see them on Ebay.

 

[A_Pmech]

I should clarify:

As Kevin mentioned, Jacob's chucks are not designed for side-loading. The "100% method" is to make a hole saw arbor which will fit in the large collet or simply use a "joint jigger" type tool.

But, if you don't have a lathe or a "Joint Jigger" and you need to get it out the door you're stuck "getting creative" figuring out how to adapt a hex arbor to an R-8. Using a drill chuck to run a hole saw not cutting to full diameter is a "get by" method which I've been guilty of using more than once.

Depending on how much tube work you intend to do, buying a "Joint Jigger" or similar might be the way to go. All the cutting forces are taken up within the tool so you can even drive it with a 1/2" hand drill. It also avoids the need to re-tram the machine.

Just a couple more thoughts I had...

 

[kool55]

I agree. A dedicated notcher is the better way to go. I just got the idea the other night thinking since I have the Bridgeport that can tilt, I could save a couple of bucks. I am making a hand rail for my steps in the shop.

 

[Kevin54]

Kool....what size of R8 collets do yo currently have right now? I may possibly be able to fix you up with something.

 

[kool55]

I have to go measure them and get back to you. Right now a bad storm is moving in.

 

[kool55]

Kevin,I have 6 R8 collets. 1/8-1/4-5/16-7/16and 5/8. I have 3 R8 tollholders,3/8-5/8 and 7/8. Iguess thats what they are. 1 has a end mill in it [ secured with a set screw].

 

[Kevin54]

Let me do some searching through my toolbox tomorrow when I go to work. I sent myself an e-mail for a reminder. I think I have something I can hook you up with.

 

[stock z/28]

Hi guys


I use mills and a small radial drill with hole saws quite a bit to notch tubing.
I prefer the radial drill now.


It uses a Morse taper chuck, the mills use R8 like you guys are talking about.

As far as collets go I "think" you can buy a collect with the hex shape in it.

As far as the cuck slipping on the arbor, I have a different view. I have a bunch of chucks and arbors. Some are very grade and are basically trouble free, but some are not. Some of the ones that slip are imported "junk" in my opinion. What I have done on a few of the "junk" ones is simply tig weld it to the arbor. It dosent take a lot. The chuck never gets close to getting hot. These are then about trouble free for "general" stuff.


I know its not considered proper to tig these but as I see it they are about worthless anyway.


I have used these with hole saws for just this application with "0" issues, with an Enco Morse adapter in a Wrong Fu imported radial dill. It works great for me

 

[-B-]

Here is one of the cheaper cutters the frame builders use http://www.novacycles.com/catalog/p...d=747&osCsid=3035edbda9f4d5ace43a50cc2cadcf22

 

[kool55]

I thought about welding the arbor to the chuck but had bad luck in the past welding tool steel. The hex R8 collet would work, but I have not seen them. The round shank holesaw might work too.

 

[stock z/28]

I dont think the cheaper versions are tool steel?


I just barely tig them with either silicon bronze or nickel, and like I said "0" problems.

 

[kool55]

What is a ER32 collet chuck tool holder used for? You can get different size collets for them . Looks like it would accept a 3/8 hex hole saw arbor.

 

[Kevin54]

An ER32 holder uses smaller collets that goes inside of the holder then a large nut shaped collar locks them in. I have not seen one that would fit in a Bridgeport. Most I have seen goes into a larger mill that uses the tapered shanks like Cat40 etc. What I thought I had in my toolbox I don't. I was sure I had a 2" cutter on a 3/4" shank that I could send your way. What you can is make a collet for a collet. Take a socket that will accept the 3/8" shank that you are using and fits snug. You may have to use a metric socket. Using a Dremel and a small cutoff wheel, split one side of the socket down from top to bottom. You now have a split bushing that you can chuck up in a standard round collet. I'll do some more looking and see if I can come up with something.

 

[kool55]

Kevin,thanks for the help. I will try the socket fab. I found the R8 ER32 tooling from a company online called Maritool. They have a 5c collet that accepts a 3/8 hex. but I did'nt see one in R8.Again I appreciate you and everyone else helping me out. Thanks

 

[Kevin54]

Kool......PM sent

 

[kool55]

Kevin, I repied. Hope you got it.

 

[Griff93]

My holesaw arbor has the regular 3/8 hex but it also has a 3/4 round section that is just above the holesaw. I've put it in a 3/4 collet and used it to notch tubing in my bridgeport without any problems.

John