Hello All Rod Builders

I recently got back into building rods again. I was using my Turncrafter Pro#TCLPRO sanding down eva grip then suddenly my mandrel got loose from the chuck at high speed. Luckily I acted fast and turn it off. Try it a second and third time ,same issue. Soo dangerous. The chuck I have on the lathe is the same kind Renzetti uses on there power wrapper. Not a good chuck for turning grips. It tends to come loose very often no matter how tight you tighted. Now I remember not using it back then. What is a good chuck to upgrade ? What is a good tail stock chuck upgrade as well? I have the tail stock live center and drill chuck. Any recommendations greatly appreciated.

Stay Safe everyone and happy building

Trung

Trung,
For using a lathe, a very excellent chuck to hold a mandrel is a drill chuck.

[www.pennstateind.com]

Also, make sure that all of your mandrels have a 60 degree center point hole drilled into each end of the mandrel.

This will allow you to use a 60 degree live center to insure that the mandrel does not come out of the chuck.

Your problem isn't the chuck - it's the mandrel.

All mandrels that are held by chuck and live center on the opposite end, should have a shoulder in the chuck end to prevent them from walking back into the chuck. If yours do not have such a shoulder, you can use a drill bit stop as a makeshift shoulder. It sounds to me like this is your problem - the mandrel is walking back into the chuck and coming loose at the live center end, resulting in a wildly spinning, out of control mandrel. Get a properly designed mandrel with a shoulder, or use the drill bit stop to act as one.

................

Here is a set of 60 degree drill point bits to use to insure that anything that you put into your lathe has a centering hole for the tail stock.

This is a link to "The little machine shop" catalog.

If you do a search for item "2504" -- this is a 1/2 inch keyed chuck for your MT2 tail stock.

Insert this "Live Center chuck" into your MT2 tail stock on your lathe.

Then, after installing your mandrel with its work on the mandrel, slide the live center chuck up and over the end of the mandrel and tighten the chuck. This will give you a 100% guarantee that the mandrel will not move either way on your lathe - even if the head stock chuck should open up.

Also, if you take your current mt2 drill chuck and insert it into your head stock, the mandrel will not be able to slide through the chuck and it will also provide a positive lock for the mandrel.

----------------------------------
I personally do not like using head stock chucks with the "johnny bars" to tighten the chuck. These chucks do not seem to give a good reliable hook up on a hard mandrel.

If possible, I would suggest that you purchase a 3 inch machine shop style 3 jaw chuck that uses a key inserted into the side of the chuck to give you a very tight and nearly fool proof method of locking a work piece into a chuck.

For example"

[www.grizzly.com]

If you buy a chuck as listed above - you will also need to purchase a lathe back that will fit your 1/8 head stock thread.

Here is a chuck back plate that will fit the chuck mentioned above and will fit your lathe.

But, understand that if you purchase this chuck and this back plate you will need to remove the head stock shaft from your lathe. Then, take the head stock shaft, the non machined back plate and the chuck to a machine shop with a good machinist and metal working lathe.

The will take your head stock shaft and will chuck it into the metal working chuck and screw on the non machined back plate. The machinist will then turn the cast iron back plate which is easy to machine with a good lathe to perfectly match your new chuck.
The machinist will drill matching holes and counter sink the holes to allow you to attach the back plate to your lathe when your shaft is back in your lathe.

By using a machinist and his lathe to machine the back plate of your new chuck you will have a chuck that will have effectively 0 run out or wobble.

Then, by using a 3 jaw machinist chuck as shown above you will be able to slide your mandrel through the lathe head stock shaft to have as little mandrel protruding from the chuck as possible to minimize and flex in your mandrel while turning grips.

I have several 3-jaw machinist chucks that I use on my lathe and in all cases had a machinist machine the blank back plate for a perfect fit on the lathe.

Then, by using the 3 jaw machinist chuck, you can slide the mandrel all of the way through the chuck so that just the end of the mandrel is exposed.
Then, chuck in the appropriate 60 degree cutting bit and insert it into your drill chuck that you insert into your tail stock.

Lock the tail stock in place so that the 60 degree bit is not quite touching the mandrel. Then, with the lathe turning on slow speed, and with the use of cutting oil you can rotate the mandrel with the stationary bit and have a perfectly centered hole milled into each end of your mandrels - if they don't come with the centering hole already in place.

Best wishes.

Tom

I got the mandrel from mudhole which have the center bore 60 degree on both ends. On my tail stock I have the live center install. So chuck up the mandrel and push tail stock against the other end. The mandrel still come loose. When I checked the chuck it is not right as previous which tells me chuck is at fault. It's kinda like wrapping a rod and sometimes the rod comes out of the chuck.


Roger,

I do have the live center on the other end. The chuck you recommended isn't that for the tail stock side only?


I would need to upgrade a chuck for the headstock. I am kinda paranoid now using the lathe until the issue is fixed. I am at the point if using it again keep thinking the mandrel gotta pop out might get injured badly.

Would a set of collet for the headstock solve my issue?

What is the difference grizzly 3 jaw compare the other brand? Like 4 jaw?

I am trying to avoid going to a machinist to custom it. Is there any other chuck that don't need modifications to my lathe?



Edited 1 time(s). Last edit at 05/13/2020 10:25PM by Trung Diep.

The mandrel needs a shoulder on it. You have two smooth surfaces with pressure from the tailstock causing those surfaces to slip. Create a shoulder and your problem is solved. Your chuck is NOT the problem.

..................

[www.woodcraft.com]

Jay Dubay Wrote:
-------------------------------------------------------
[www.mudhole.com] { keep a collar pushed tight to the chuck}

[www.lowes.com]



Edited 1 time(s). Last edit at 05/14/2020 05:43AM by Jay Dubay.

Trung,
The other posts make good suggestions on using a stop on the mandrel to keep it from going into the chuck.

On that same vein, it is a good idea to be able to insert the mandrel all of the way through the lathe chuck to keep the distance from the face of the lathe chuck to the work piece as short as possible.

Your basic issue is your chuck. You should be able to tighten your chuck and no matter how much pressure you put on the work piece, the chuck should not get more loose.

Just for a bit of maintenance, Be sure that the internal workings of the chuck are 100% clean and free of any dirt, rust, or other items that may keep the chuck from getting tight. Also, a light coating of machine oil on the internals of the chuck will help a bit.

Since you have the type chuck you have, you have a pair of johnny bars to tighten the chuck. I don't know how long your johnny bars are, but if you can obtain some drill rod and make johnny bars that are 10 inches long or so, it will help to get the chuck really tight.

----------------------------------
But, in addition to the comments listed above by others as well as myself, consider the purchase of a "live center drill chuck with an MT2 pin on the back.

For example:

[www.amazon.com]

This chuck style live center should completely solve your issue - even with no shoulders on the mandrel.

Slip your mandrel into the lathe chuck so that the chuck end of the work piece is about 1/2-1 inch from the face of the chuck. Then, having left about 1 1/2 inchs of mandrel extending past the work piece or grip being worked, insert the tail stock end of the mandrel into the new rotating tail stock chuck. Then, tighten the chuck with the key and go to work.

p.s.
When you insert the chuck style live center into your mt2 tail stock, move the tail stock to the face of the chuck, lock it down and then advance the tail stock into the face of the chuck, so that you can be sure that the live center chuck is well seated into the tail stock. Then, unlock the tail stock, slide it back down the bed of the lathe to be in a position for using the lathe with your mandrel.

----------------------------------------------------
The basic root cause problem that you are having is that you are using a wood working chuck with the johnny bars on a metal working application. i.e. chucking the hardened mandrel into the jaws of your wood working chuck.
Hence, my initial recommendation to use a metal working chuck on your turn crafter lathe to hold the "METAL" mandrel that you use for your grip shaping.
But, without replacing your current chuck with a metal working style locking chuck with its rotary key, the use of the live center chuck in the mt2 tail stock is a very good solution to your problem at a reasonable cost.

------------------------------------
But, an even less expensive solution is a set of mandrel collars as some of the folks above have mentioned which will also solve your issue. If you do happen to find that you still get mandrel slippage using a collar with a set screw to make it tight - you can also first find the location where you want your mandrel to be, and then take a dremal tool and grind a small depression in the mandrel so that the set screw on the collar will have a shoulder to lock into and avoid slippage. The depression does not have to be very deep at all. Just a slight depression to give a crater for the set screw to lock down the collar.

Jay,
Thanks for the wood crafter link to the drill collars. I will have to pick up a set of these collars.

Take care

I use a Nova G3 chuck on my lathe. I use home made .250 mandrels all the time steel/aluminum/wood without slippage using a live center. However I would recommend a mandrel saver, it prevents putting any pressure on the headstock and possibly puting too much pressure from the tailstock and bending your mandrel. Even if your mandrel did come loose, if using a mandrel saver in your tailstock it is still captured.

Edited for typographical error



Edited 1 time(s). Last edit at 05/14/2020 02:06PM by Jonathan Hotham.

I just purchased a set of mandrel collars. Thanks Jay!!!!


To my understanding , I put the mandrel collar against the headstock chuck to prevent the mandrel from slipping? Is this what Tom is referring about, Shoulder stop?


Thanks Everyone. Greatly Appreciated.

Hopefully I can feel confident now going forward with the lathe

The surest and safest method of holding mandrels on a lathe is with collets! They grip the mandrel tighter than any chuck can and cannot loosen up.



Edited 1 time(s). Last edit at 05/14/2020 10:10PM by Phil Erickson.

Thanks Phil

I will look into it. I think Penn State Industries do have a set of collets

Trung don't Thank Me, {Thank Tom!} I just chimed in. But yes you have the correct idea, And how I do it as well with my small 4 jaw wood lathe chuck Also keep in mind as well that 1/4" mandrel's do flex much more then 3/8" so If your using 1/4" watch how much pressure you are applying when shaping. I personally use no smaller then 3/8" mandrel's and use 3/8 bored cork rings,- [www.mudhole.com] Same when shaping foam core's and skinning with carbon fiber. That's just my preference, I simply don't build on blanks the require that of small of a ID bore, So that's less reaming to do on my part. Cheer's and tight lines!!



Edited 1 time(s). Last edit at 05/14/2020 07:39PM by Jay Dubay.

Trung, yes Peen State has a mandrel set that I use.

Trung,
You asked a question on why is it necessary when replacing a flat backed chuck with a partially machined lathe back plate is because of "threads"

Every set of threads is slightly to a lot different. So you need to remove the head stock on your lathe, chuck it into the chuck of a metal working lathe and screw on the partially machined chuck back plate.

Then, use the ability of the metal working lathe to insure that the face of the new back plate is perfectly true, and of the correct size to perfectly fit the new chuck being mounted on the lathe in question.

--------------------
You can ask the question - why is machining not required on the chuck when an MT tapered peg used to mount a chuck. The answer is simple - an MT mount does not involve threads.

The specifications for an MT mount is spelled out in great detail which can be easily replicated on any CNC milling machine

This means that any lathe accessory that uses an MT mounting system, the accessory will always run dead true.


Also, if you have a particular lathe head stock shaft and a new back plate is screwed onto the threaded end of the head stock threads, and then machined to be flat and of the correct size to fit into the back of a new lathe chuck, the new lathe chuck will run true.
But, if you purchase a prethreaded back plate - chuck - the chuck may or may not run true on your particular machine.

But, for mandrel use for rod building, it is ultra nice to use a 3 jaw metal working chuck that has 0 runout or wobble when holding a mandrel in a non slip configuration.

There is another reason that I like to use a metal working chuck on my lathe.

I do a lot of metal shaping as well as shaft drilling. It is easy to chuck the work piece into the head stock chuck, chuck a drill bit of the appropriate size into the tail stock and then turn on the head stock chuck at a slow drilling speed to avoid overheating the object being drilled and simply advance the stationary drill bit into the spinning work piece.

For example:

[www.rodbuilding.org]

Notice that I am using a ball bearing equipped steady rest to support the non chuck end of the grip being drilled by advancing the tail stock held drill bit into the spinning grip.
this method always insures that the hole will be in the dead center of the spinning work piece.

For the record, the chuck supplied on the Renzetti is a Taig 3-jaw, self centering, metal working chuck.

...........

Thanks Roger

Very nice lathe you got there.

Tom,

Yes, the chuck I have on the wood lathe is the Taig- 3 Jaw same as my Renzetti lathe. I have order the mandrel collar set. Hope that will solve the issue.

Anyone know the model number for Nova G3 chuck? Do I need to get an adapter for it?



Edited 2 time(s). Last edit at 05/15/2020 11:14AM by Trung Diep.