New 3-jaw chuck

[rleete]

I have a Homier Speedway lathe. Made by Seig, it's pretty much the same 7x14 that Grizzly, HF and others sell. It came with a 3" 3-jaw chuck, which I have been using and abusing for many years. I recently took it off to mount my 5C chuck adapter plate and decided to open it up to clean out the years of accumulated debris. It was thoroughly cleaned and lubricated when I got the lathe, but that was decades ago. It was cleaner than expected, but there is noticable wear.

It hasn't been very smooth operating for quite a while now, and part of the reason is the slop between the bolts that hold the pinions in place and the pinions. The scroll is also somewhat sloppy. So, while I decide if I should make new bolts/pins, I'm also leaning towards just getting a new chuck. I figure I might go for a 4" model, which will accommodate more of the parts I usually make without having to swap jaws. This would also free up the old chuck to use on the mill if I needed.

LMS has their "standard" one (with adapter) for just under $150. They have a "premium" one for $150, but the adapter is another 25 bucks. Amazon and eBay have dozens of choices for 70 dollars and up. While I'd like to give my business to LMS, their prices are a bit on the high side. Grizzly prices are no better.

Is there any reason to go with a 5" over a 4"? I've read (way back when) that a 5" was too much mass for the motor to handle long term. Is that really an issue?

Any recommendations? Any specific ones to avoid?

 

[jrslogs52]

For smaller parts the 4" chuck with the lighter jaws will take less pressure to hold delicate parts.

 

[kwoodhands]

I have a Homier Speedway lathe. Made by Seig, it's pretty much the same 7x14 that Grizzly, HF and others sell. It came with a 3" 3-jaw chuck, which I have been using and abusing for many years. I recently took it off to mount my 5C chuck adapter plate and decided to open it up to clean out the years of accumulated debris. It was thoroughly cleaned and lubricated when I got the lathe, but that was decades ago. It was cleaner than expected, but there is noticable wear.

It hasn't been very smooth operating for quite a while now, and part of the reason is the slop between the bolts that hold the pinions in place and the pinions. The scroll is also somewhat sloppy. So, while I decide if I should make new bolts/pins, I'm also leaning towards just getting a new chuck. I figure I might go for a 4" model, which will accommodate more of the parts I usually make without having to swap jaws. This would also free up the old chuck to use on the mill if I needed.

LMS has their "standard" one (with adapter) for just under $150. They have a "premium" one for $150, but the adapter is another 25 bucks. Amazon and eBay have dozens of choices for 70 dollars and up. While I'd like to give my business to LMS, their prices are a bit on the high side. Grizzly prices are no better.

Is there any reason to go with a 5" over a 4"? I've read (way back when) that a 5" was too much mass for the motor to handle long term. Is that really an issue?

Any recommendations? Any specific ones to avoid?

The 5" chuck is not practical in my opinion. If you chucked a large round then the jaws may hit the bed. I have the LMS 4" scroll chuck, the premium one with back plate. Runout is almost nil. The chuck body is within .00015
With a test rod from a printer the runout is .0018 in 10" supported with the tailstock.
This is on a 7x12 Cummings lathe. Actually 7x14 , labeling is 7x12 . I bought this chuck so I could leave the original 3 jaw on a rotary table.
mike

 

[ninefinger]

also consider an ER32 chuck and some collets. I bought one for my little Emco Compact 5 and its been great and probably not really much different in price (except at LMS...). With a full set of collets (1/32" steps) I can hold any diameter up to 13/16" and with less overhang than the 3 jaw (more rigid setup). Safer too as its also much harder to forget the chuck "key" (collet wrench) as it falls off!

 

[Apprentice707]

This is an interesting dilemma, I had a Harbor Freight 7 x 12 lathe that I bought secondhand and this served me well for nearly 15 years. It would still be serving me well but I have sold my holiday home in Florida and I have now retreated to my home in the UK as my last move. I never liked the chuck mounting arrangement on the lathe but learned to live with it.

I too experienced wear in the chuck supplied with the lathe and decided to replace it with a 4-jaw self-centering chuck 4 inches in diameter. My reasoning for this was that as I machined mainly round and square stock I could machine either without having to change chucks, of course, I had to do this if I machined hexagonal. If I remember rightly I paid about $80 for it off Fleabay and I machined a piece of 1/4" steel plate for an adapter, the result was satisfactory with good centricity and very little runout. I retained the 3-jaw chuck after cleaning it and I also had a 4-jaw independent chuck for the odd-shaped item. LMS prices did always seem a bit steep but I have used them for the odd thing and been happy with my purchases.

Further with the subject of chuck mounting on the 7 x 12 lathe I modified the mounting studs on each chuck and faceplate by machining a small spigot on the thread of each stud thus allowing me to easily locate the nuts onto the studs given the restricted access between chuck back and headstock casting. I used 3 MT collets with a drawbar but this was because I had a spare set from my milling machine in the UK so I transferred them. Ideally, I would have used ER collets but no harm in saving a penny or two.

If you haven't nodded off by now I would like to share my thoughts on the 7 x 12 (14 or 16) with you. Having bought the lathe secondhand I first stripped it down and checked all components for any signs of wear and maladjustment. I decided that I would replace the headstock bearings with some made by a US manufacturer (This was recommended by an acquaintance who had done this to his lathe and I saw the advantage) and file and scrape the slideways into a better fit. I also added locking nuts to the gib adjustment screws to stop creep. The feed screws were in acceptable condition but I did add a piece of plastic pipe over the leadscrew at the left-hand side of the carriage to prevent ingress of swarf onto the leadscrew.

All in all this little lathe served me well, it isn't a Myford or a South Bend but it was adequate for my needs and didn't cost a fortune. I used a vertical slide on it for light milling and again it didn't falter. Well done Chinese People for selling us this world lathe.

Best wishes

Brian

 

[ShopShoe]

rleete,

Over the years I have had my 7x lathe I have acquired 3-inch, 4-inch, and 5-inch chucks, so I can speak to this.

The 5-inch takes too much away from the motor, so ends up not having very much torque left over for cutting. It also makes a heck of a flywheel and keeps spinning when you want to slow down or stop. Adjusting the motor controller could make it behave better if you wanted to run it all the time, but I only have used it when certain job requirements made it necessary. I also think it's too hard on the bearings and drive train.

The 4-inch is not too bad in performance, but after going back and forth between 3-inch and 4-inch chucks I ended up deciding the 3-inch is really the best for this lathe, or my lathe anyway. I sometimes need the 4-inch for certain jobs, but the 3-inch is my main choice.

A few years ago I went about making a whole series of changes and improvements to the lathe and ended up deciding to get a premium 3-inch Bison chuck from one of Bison's distributors and I am not sorry I did that. It cost over $300 pre-COVID-prices, but it is the best-made of all the chucks I have. (I wrote a thread about my lathe improvements on this forum: ShopShoe's Mini-Lathe Upgrades in the "Machine Modifications" area.) (Usual Disclaimer: I am not afiliated with Bison or their distributors other than as a customer.)

I also have various collet options and I consider them very useful as well. And I think I would not be remiss to mention that sometimes certain jobs do require a faceplate from time to time.

Let us know how you proceed.

--ShopShoe

 

[rleete]

After more consideration, I have decided against the 5" chuck. I do have a recently purchased 5C chuck (I already had all the collets) which I need to finish mounting. This uses a 5" adapter plate, and this alone has convinced me that it's really too big for the lathe.

Problems with the 3-jaw currently seem to involve the studs which secure the pinions in the chuck. They are all very loose. This allows the pinions to slip out of place and bind on the scroll gear. I have the proper screws (M5?), which I will turn down to fit better. The scroll had burrs up on the end where it starts. Judicious use of needle files has cleaned it up nicely.

And just to note that I have, and probably will continue to order from LMS. Their customer service is exceptional, and that alone is reason to do business with them.

 

[xpylonracer]

also consider an ER32 chuck and some collets. I bought one for my little Emco Compact 5 and its been great and probably not really much different in price (except at LMS...). With a full set of collets (1/32" steps) I can hold any diameter up to 13/16" and with less overhang than the 3 jaw (more rigid setup). Safer too as its also much harder to forget the chuck "key" (collet wrench) as it falls off!

.
Which type of ER chuck did you use, MT tang type or backplate mounted ?

xpylonracer

 

[ninefinger]

For the Emco I bought a backplate mount, as I had already made an adapter from the Emco's spindle nose to the chucks used by the mini-lathes.
I had to drill holes to bolt it on as it had a bolt pattern with threaded holes and I needed 3 clearance holes, but a carbide drill worked a charm on the semi hardened steel. (don't mind the swarf in the picture - was machining 18 valves for my radial build.)

 

[ninefinger]

After more consideration, I have decided against the 5" chuck. I do have a recently purchased 5C chuck (I already had all the collets) which I need to finish mounting. This uses a 5" adapter plate, and this alone has convinced me that it's really too big for the lathe.

Problems with the 3-jaw currently seem to involve the studs which secure the pinions in the chuck. They are all very loose. This allows the pinions to slip out of place and bind on the scroll gear. I have the proper screws (M5?), which I will turn down to fit better. The scroll had burrs up on the end where it starts. Judicious use of needle files has cleaned it up nicely.

And just to note that I have, and probably will continue to order from LMS. Their customer service is exceptional, and that alone is reason to do business with them.

FYI - I have nothing against LMS - didn't mean to come across that way. I have bought from them as well and agree that they have great service and a broad range of products for small machines (as their name implies). But being in the great white North, everything I buy from the US is subject to currency exchange and typically high shipping charges and bogus brokerage fees from the shippers regardless of the vendor, so I tend to cheap out wherever I can to make my hobby bucks go further.

 

[pete]

I also live in the great white north and have dealt with those added on brokerage fees more than a few times myself. One tip you might try, but not all company's will do so. Have your orders shipped through USPS, it still goes through customs, but there's no broker used. In my little town I get my mail in a post office box at the local post office. My shipment comes in, I get a notification in that P.O. box, then pay the sales tax at there counter. It's the cheapest method I know of for anything like this.

In reality, 3 jaw chucks are more of a convenience than an absolute requirement. As proof of that, everything ever required before they were invented was still accomplished using a face plate and various add on work holding methods, or between centers. Yes they obviously do speed up the work holding, but if your having to remove the work at any point and swap it end for end, there will always be a certain amount of run out. Even the best 3 jaw chucks for manual use will exhibit at least some. Buying the absolute best you can afford does pay off as ShopShoe said, and the heavy duty designated one's I bought for my C5 Emco were a few multiples in price of those LMS chucks. I suspect mine were actualy built by Bison and there price sure seemed to indicate that. I also have the same in a 4 jaw scroll chuck. In hindsight I'm not sure I'd buy one again. The idea behind them seems much more useful than the real world usage is. With a highly accurate low run out chuck, standard square bar stock simply isn't made accurate enough across the flats on all 4 sides for the jaws to grip all 4 sides evenly. And that includes cold drawn bar stock. I'd suggest there really designed more for second op work where the bar has already been machined to close dimensions so the jaws will grip evenly. At that point then they are a handy chuck to have, but with a bit more time, a 4 jaw independent can do everything those can plus a whole lot more.

 

[MRA]

I ummed and ahhed before putting an 8" (!) 3-jaw chuck on my Boxford (SB 9" copy for US readers). It's too large, and too heavy - but it has a wacking great hole in the middle which makes holding and centering larger stock very easy. I don't run it very fast, and I have to watch that the jaw ends don't hit the bed. But over all, I really like it. It came for free, as did a similar 4 jaw a bit later, and I just had to make backplates for them both. Maybe if I destroy the spindle bearings I'll regret it, but OK so far. My car wheel bearings take a lot more load for much much longer periods, with similar dimensions and overhang - well, that was my reasoning.

I just mention this as there wasn't much enthusiasm for larger chucks further up this thread - and I have found one quite useful.

 

[pete]

To properly judge what any lathe is capable of handling as far as chuck weight, I think its better to look at it from the perspective of what the manufacturer designed it to do. And any correctly designed lathe would have been done using proper mechanical engineering load calculations. Lets say for example a lathe has a maximum part diameter of 4" over the cross slide and 24" total part length. A steel bar of those dimensions weighs roughly 85 lbs supported between the head stock chuck and the tail stock center. Or 42.5 lbs at each end. Plus whatever the OEM supplied chuck would be. Added to that would be a (and I'm only rough guessing) safety and part durability factor of at least 3-5 times that weight. Very well made live centers always give a maximum loading limit in weight. Even the MSC house brand AccuPro MT 3 live center shows a maximum work piece load of 1100 lbs. and that's at just one end of the lathe. Obviously the further you move away from that front spindle bearing, the load limit reduces without additional tail stock support. For some industrial rated lathes, the manufacturer's show and allow lifting at least part of the weight of the lathes head stock end by lifting while straps are attached to the spindle nose. I wouldn't do so, but in some cases it's still accepted practice. You also have to look at the maximum swing and part depth the lathe could be asked to do without any extra support from that tail stock. With a 10" swing lathe then a 9" dia. x 3" thick plate of round stock wouldn't be out of the question if it was attached to something like a face plate. About 54 lbs for stock of that size. Seriously out of balance parts held offset on that face plate or 4 jaw would I think be much more detrimental to those head stock bearings than a larger than OEM supplied chuck. But like anything else, the higher and longer you load anything mechanical, the shorter it's long term life span will be. Used within reason, those larger chucks shouldn't be an issue.

 

[rleete]

Just for some closure to this thread, I thought an update was in order.

I ordered a generic 4" diameter 3-jaw chuck from eBay. I arrived in the usual packaging, which was all but destroyed. The chuck, although deeply scratched, was in otherwise good shape. I disassembled it to clean out the ubiquitous grease and dirt, and was pleasantly surprised to find the jaws (both sets) and chuck were already marked with clearly stamped numbers. Fit and finish of all parts was worlds better than the 3" chuck that came with the lathe. There was also a lot less dirt and gunk inside than expected.

I cleaned, reassembled, and stoned out the burrs from the scratches. It functions smoothly with no catches, holds tightly and fits the adapter plate perfectly. I have yet to mount it, as I have a setup in the lathe currently that I didn't want to disturb. I have no doubt that I will be happier with this chuck than the one I have been suffering with all these years.

Thanks for all the information provided.