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View Full Version : Expanding mandrels.. Handy?



keth524
02-26-2015, 05:24 PM
I have a local with a like new set of K.O. Lee expanding mandrel set, 5 piece I believe, for 300.00 does anyone have any input on how handy these tools are?

Blogwitch
02-26-2015, 05:32 PM
I have these sets here, the second set down the page.

http://www.arceurotrade.co.uk/Catalogue/Expanding-Mandrels

Luckily they were bought for me when I was setting my new shop up.
Very good at what they do, but unless you can get the use out of them, they can be a bit of an expensive dust gatherer, like a lot of other tooling I had bought for me.

John

Toolguy
02-26-2015, 05:48 PM
When you need them they're a lifesaver. It depends on the kind of work you do. The K.O.Lee ones will be good quality. The good ones are expensive, worth it only if they get used.

Carm
02-26-2015, 05:51 PM
Handy, yes!
There are lots of workarounds but that's often expedient and hassle free, if you can choke the change.

oldtiffie
02-26-2015, 05:54 PM
First I've seen of them.

A really good product all round that really does fill a void.

Expensive but would be great and probably well worth the cost if needed.

I've bought a bit of stuff over time from arceurotrade (UK) and their costs may seem a bit high to some but all that I've received from them have been excellent and so far as I am concerned have been very good value.

J Tiers
02-26-2015, 08:04 PM
The first type in the link are great. I use them all the time for things which will not fit a standard drive-in mandrel.

The second type might be, but I have never used any.

lakeside53
02-26-2015, 08:04 PM
I have a full set (about 8 pieces) . Very useful for machining pulleys, wheels etc... anything where grabbing the OD or ID in a chuck doesn't work, and/or work between centers.

JCHannum
02-26-2015, 08:29 PM
They are good to have when nothing else will work, but were primarily made for use with grinders and will not take heavy cuts in the lathe. I have accumulated a fairly complete set up to 1-1/2" capacity and would not part with them though they only see occasional use.

JoeLee
02-26-2015, 09:02 PM
They are good to have when nothing else will work, but were primarily made for use with grinders and will not take heavy cuts in the lathe. I have accumulated a fairly complete set up to 1-1/2" capacity and would not part with them though they only see occasional use. I agree, they were designed for use with grinders where a minimum amount of force is applied to the part. They are just a wedge fit. Not really enough holding force for lathe work. I've seen many of them slip and score up the tapered shaft.

JL................

JRouche
02-26-2015, 09:03 PM
I have a set and really like them. Out of curiosity, what is the proper way to "seat" them. You know, lock the part in place. Im sure I have been doing it wrong (but still works) so I wont divulge that info :o JR

JoeLee
02-26-2015, 09:41 PM
I think there is only one way to seat them. Place the part over the expanding sleeve and tap it home.

JL...........

lakeside53
02-26-2015, 09:46 PM
I make sure mine are dry (no lube). Mount the part to be turned, tap firmly with a hammer. Done.

I turned 2.26 x6 2 inch aluminum wheels on them from SQUARE stock - never had any slip...

This is using the 1.5 inch set:

http://i238.photobucket.com/albums/ff150/lakeside53/x72%20Belt%20grinder/DSCN1646Medium.jpg (http://s238.photobucket.com/user/lakeside53/media/x72%20Belt%20grinder/DSCN1646Medium.jpg.html)


A poly-vee pulley using the 1 inch set.
http://i238.photobucket.com/albums/ff150/lakeside53/x72%20Belt%20grinder/DSCN1640Medium.jpg (http://s238.photobucket.com/user/lakeside53/media/x72%20Belt%20grinder/DSCN1640Medium.jpg.html)


Here's how I drive them (shop made) - the a series of adapters inside the center section to adapter the different od's.
http://i238.photobucket.com/albums/ff150/lakeside53/x72%20Belt%20grinder/DSCN1633Medium.jpg (http://s238.photobucket.com/user/lakeside53/media/x72%20Belt%20grinder/DSCN1633Medium.jpg.html)




They are flexible so it's easy to get them to "sing" (chatter) though. Try to keep them as short as possible, and fiddle with speed and feed.

J Tiers
02-26-2015, 09:46 PM
Arbor press...... For seating them as well as tapered mandrels, and also for removing them.

JRouche
02-26-2015, 10:40 PM
I thought I read somewhere that an arbor press was used. I have just been using gravity. Mount sleeve and part on spindle and "drop" or tap with force the end of the spindle on a wood or white plastic cutting board. Keep tapping downward till its firmly seated. Never had one slip. Thats if the part is heavy enough. If its light or a thin walled part, say some tubing I will use a scrap piece of round metal (many sizes in my garage) that catches the tubing but slides over the sleeve and kinda tap it tight. JR

JoeLee
02-27-2015, 12:08 AM
If your mounting thin wall tube on the expanding mandrel too much force can expand or stretch the part.

JL.................

Firecracker
02-27-2015, 04:00 AM
Used the tap off/on type before, as people have said not for every job, but unbeatable when needed.

I also use regularly the 'home rolled' variety. Take a bit of scrap mild steel, ally, whatever. Turn end to required diameter. Centre drill and drill suitable tapping size down centre (for 1"OD, say 1/2". BSW). Now remove from lathe (having marked jaw 1 if holding in 3-jaw) and first tap hole, but using a first tap, so top 2-4 threads are full depth, then thread depth reduces. Take hacksaw and put two cuts into end, 90deg apart. Replace in chuck, run suitable bolt down hole, load work onto mandrel and tighten bolt. These can be turned down at a later date to suit other jobs.

One of these homebrews was used at work to hold a batch of custom large copper washers (2-1/2" OD, 1" ID)They'd been parted off a bar ( which had been the usual joyous experience of parting copper) then had the ID deburred, then were slung on the mandrel to clean up the faces. If I remember come Monday I'll retrieve it and do a photo if anyone's interested.

Owain

Euph0ny
02-27-2015, 04:29 AM
You can watch Adam Booth using an expanding mandrel to hold a motorcycle wheel for turning in this video:
http://youtu.be/2z57zqbaXT4

Abner
02-27-2015, 07:02 AM
I have an old set I believe from Enco that are the type firecracker describes. Hex cap bolt down the middle. Used them only a couple of times and like others have mentioned you cannot take heavy cuts at all or even light ones with big diameter stuff. I also found my ability to tighten them was limited. The set you are looking at is more precision and looks like they would hold better.

RussZHC
02-27-2015, 07:10 AM
As owain said, that is the main reason I have collected more than a few sizes of tapered pipe taps, same principle. Heavy and light cuts are all relative.

keth524
02-27-2015, 06:02 PM
http://www.ebay.com/itm/K-O-LEE-Expanding-Mandrel-Set-M101-/231488683095?pt=LH_DefaultDomain_0&hash=item35e5ccfc57#
this is the set im talking about in particular!

Fasttrack
02-27-2015, 06:08 PM
Arbor press...... For seating them as well as tapered mandrels, and also for removing them.

Indeed ... didn't we see an arbor press on the forum that was made specifically for mounting on the bed of a lathe just a few months ago? I thought that was an interesting idea but my lathes are too short to sacrifice bed length for a press that would get used once in a blue moon... as others have said, expanding mandrels can be a lifesaver but not usually a "must have". If you've got some extra cash you want to spend on your shop, I say go for it. If you're deciding between spending your money on that or something else, well the something else may be more practical.

Black_Moons
02-27-2015, 06:46 PM
Used the tap off/on type before, as people have said not for every job, but unbeatable when needed.

I also use regularly the 'home rolled' variety. Take a bit of scrap mild steel, ally, whatever. Turn end to required diameter. Centre drill and drill suitable tapping size down centre (for 1"OD, say 1/2". BSW). Now remove from lathe (having marked jaw 1 if holding in 3-jaw) and first tap hole, but using a first tap, so top 2-4 threads are full depth, then thread depth reduces. Take hacksaw and put two cuts into end, 90deg apart. Replace in chuck, run suitable bolt down hole, load work onto mandrel and tighten bolt. These can be turned down at a later date to suit other jobs.

One of these homebrews was used at work to hold a batch of custom large copper washers (2-1/2" OD, 1" ID)They'd been parted off a bar ( which had been the usual joyous experience of parting copper) then had the ID deburred, then were slung on the mandrel to clean up the faces. If I remember come Monday I'll retrieve it and do a photo if anyone's interested.

Owain

Very similar to one I made except I found unformed threads ruined cheap bolts REAL quick
My MK2 was to drill the end of the hole with a 1/2 size drill bit, lets say your using a 1/2" bolt, use a 1/4" drill and drill another 1/2" deep past the end of the 1/2" tapped hole

Then turn a shallow taper onto the end of your 1/2" bolt to engage in the 1/4" hole, the 1/4" hole will take a bit of a taper at the mouth as needed and the bolt tip won't be too badly mangled and will survive quite a few more uses with less wear then using the threads.

oldtiffie
02-27-2015, 07:52 PM
Use a bit of "pipe" with ends machined flat/square that fits fairly easily over the mandrel and use the pipe as a "drop" or "dead" hammer.

Only a few blows or "drops" are needed to secure the job to the mandrel and to loosen it.

Can be done anywhere.

Arbor (or any) press not needed.

Same principle as a "drop hammer".

J Tiers
02-27-2015, 08:33 PM
... as others have said, expanding mandrels can be a lifesaver but not usually a "must have". .....

Depends on what you do. If you can afford to make a lot of different sized mandrels as you need them, no you don't need expanding ones. Same if you never need to do that sort of work.

Standard tapered mandrels are very tightly sized, and a tiny error from nominal size will make them fall through to where they are not useful. And unlike collets, they don't overlap in size. Expanding ones work on off-sizes.

Black_Moons
02-27-2015, 10:04 PM
Indeed ... didn't we see an arbor press on the forum that was made specifically for mounting on the bed of a lathe just a few months ago? I thought that was an interesting idea but my lathes are too short to sacrifice bed length for a press that would get used once in a blue moon... as others have said, expanding mandrels can be a lifesaver but not usually a "must have". If you've got some extra cash you want to spend on your shop, I say go for it. If you're deciding between spending your money on that or something else, well the something else may be more practical.

I am not exactly sure id be willing to put that kinda force on my bed!

Fasttrack
02-27-2015, 10:12 PM
I am not exactly sure id be willing to put that kinda force on my bed!

Here's the thread:
http://bbs.homeshopmachinist.net/threads/65441-_-The-resurrection-of-a-Greenerd-3-1-2-Ratchet-Arbor-Press-begins?highlight=arbor+press

And a picture of the massive beast:

http://site.thisisjusthowidoit.com/sites/default/files/brilliant_gallery_temp/bg_cached_resized_767ed12ad2f538df599e131d6e107a12 .jpg

Notice the inverted V on the base of the press...

oldtiffie
02-28-2015, 02:12 AM
Expanding mandrels are handy to have but are not a panacea for all work where the bore of the job if the reference.

If say heavy cutting as on a lathe or when gear-cutting on a mill the mandrel must be oriented so the it is being pushed toward the larger end of the mandrel which can either gat "hammered" going on (as above) or forced off if machining pushes the job toward the "smaller end" of the mandrel.

I much prefer a parallel spigot which the job is seated on with a screw and nut holding the job onto the mandrel.

I'd be more inclined to use the mandrel on a grinder (cylindrical or tool and cutter grinder/s).

Blogwitch
02-28-2015, 04:07 AM
I'm just wondering how far some people would actually go. Maybe a 500 ton steam press!!
I showed on the second post the ones that I have in my possession, and for what they are, they do an admirable job, they work on a back to front system similar to ER collet chucks and if the bore of the part is long enough to straighten itself up onto the expanding collet, then they do a very good job, without having to bash them with a sledge hammer.
If you are going to be going to the trouble that some of you seem to want to, then maybe a different method would be more suitable to your type of working. Maybe welding or loctiting the piece part to a mandrel, for all us others who just want an easy way to turn something simple, then what I showed is a good method, but as I said, rather expensive to be a permanent dust gatherer in your shop that would be used once every year or so.

John

JCHannum
02-28-2015, 07:38 AM
The expanding mandrels are useful tools and are an expedient when they can be used. However, they are not the be-all and end-all of workholding by the ID.

The adjustable mandrel with the expansion screw in the end can be purchased in sets or shop made as needed very simply.

Another simple device can be made by turning a stub arbor to the diameter of the ID and then milling a flat almost half that diameter. The part is placed on the arbor and a suitable piece of round stock that is almost the diameter of the flat is placed in the gap and the part is given a twist to lock things up. This acts like a simple sprag clutch and will retain the part for machining.

Once used, the shop made arbors and mandrels are kept together for future use or to be modified as needed.

Seastar
02-28-2015, 08:12 AM
JimH
Now that's a good idea.
Haven't seen that before ----- thanks!
Bill

JCHannum
02-28-2015, 08:54 AM
I can't claim originality, but give all credit to Phil Duclos for the idea. It works and is simple enough to make. I keep an assortment of dowel pins handy for this.