Work-holding on a larger mill?

[Frank O]

For some years I did my milling on the mill segment of a Grizzly G0516, basically their version of a Sieg X2. This usually involved small work pieces held in a 3" screwless vise. Recently I've started working with a Little Machine Shop 5550 mill, a version of a Sieg X2.7. One of the motivations for the mill upgrade was to be able to work with larger pieces.

Right now we have a series of 6" x 6" x 5/8" aluminum plates that we need to cut some slots in. Won't fit in my little vise, so I thought we'd clamp it directly to the table. The problem was that, using the bolts and blocks I could find in my clamping kit, the bolts stuck up too high for the end mills to be able to reach the work piece.

So some questions.

First, if I'm having trouble getting this done with the clamping kit, am I just thinking this through the wrong way? The kit is a pretty standard one from LMS (https://littlemachineshop.com/products/product_view.php?ProductID=1144).

Second, are there a good low-profile clamps I can look for to hold down work pieces in the size range mentioned?

Third, any suggestions on a vise I might look at for this size of work piece that wouldn't completely wreck my budget?

And finally, anything good to look at in the way of videos, articles etc that might get me more up to speed on work-holding in this size range?

 

[RobertB]

Get shorter bolts? Longer end mill? a picture of your setup would help.

 

[mikey]

Have a look at Mitee-Bite clamps. There are lots of videos on them.

 

[higgite]

Any chance of using some sacrificial material under the plates to jack them up enough that the clamping screws aren't protruding too much? I've also done that with 1-2-3 blocks for items that my vise couldn't handle. (only for operations that didn't endanger the 1-2-3 blocks... so far. )

Tom

 

[Janderso]

I don't know what the difference is but I bought the blue set from Travers. It was more money but it didn't have the stinky gritty oil coating like the red set I had that I lost in the fire.
I bought 2 sets of the blue, good quality. IMHO
I also have these. Plus, I inherited a set of 3/8" with up to 8" bolts/studs. Fixturing/holding is half the battle.

 

[epanzella]

I'm having trouble understanding the problem. With the longest holdowns in your kit the bolts would be 2 or 3 inches away from your part. How will that interfere with your end mill? Your kit uses 3/8x16 bolts. In a pinch you could cut up threaded rod to any length you wanted. Your kit looks like the pic below right?

 

[Frank O]

Thanks for all the comments.

I'm having trouble understanding the problem. With the longest holdowns in your kit the bolts would be 2 or 3 inches away from your part. How will that interfere with your end mill? Your kit uses 3/8x16 bolts. In a pinch you could cut up threaded rod to any length you wanted.

Great points. I looked further and found that the longest holddowns had snuck off to a different drawer, and using them allowed the bolts to easily clear the spindle. Good idea about threaded rod, I think we may already have some 3/8x16 and will keep in mind we can use that if ever needed.

Any chance of using some sacrificial material under the plates to jack them up enough that the clamping screws aren't protruding too much? I've also done that with 1-2-3 blocks for items that my vise couldn't handle. (only for operations that didn't endanger the 1-2-3 blocks... so far. )

That would be another good fix. We were in a little bit of a hurry, and I wasn't seeing any handy material that was sufficiently squared-up to work.

Have a look at Mitee-Bite clamps. There are lots of videos on them.

Thanks, will check them out.

I don't know what the difference is but I bought the blue set from Travers. It was more money but it didn't have the stinky gritty oil coating like the red set I had that I lost in the fire. I bought 2 sets of the blue, good quality.

Okay, found the blue sets on the Travers website:

https://www.travers.com/52-piece-deluxe-clamping-sets/p/94452/

As you say, kind of pricey. Will have to check out which one I need for this mill.


Anyway, I think I'm good for now, but I'm still interested in upping my work-holding chops as we do more work with larger pieces on this mill. Any other suggestions (bigger vise?) would be gratefully accepted.

 

[Larry42]

When I got my used mill it came with a Chinese vice that had jaws that would flex and release the work. Finally bit the bullet and bought a Kurt 6". Problem mostly fixed. I came by a Palmgren swivel base vice that I mount when I need to support long parts that stick out too far from the Kurt. The two vices work together OK with some shimming. You might look into getting a 2 part vice that bolts to the table at any spread you want. I've made some "special" hold downs when nothing in my kit would work. I've got a cans full of the bolt sizes that fit my T nuts also. Then there is the issue of the mill, lathe face plate and the rotary table taking different size T nuts & studs. The 8" RT always seems to be just a bit too small even with my 11" top plate. I've made a few long T nuts that extend the clamping area of the RT. I screwed the plastic clamping set racks to the wall behind the mill, can see what I need and makes it easy to put parts back where they belong. Work holding is more than half the battle!

 

[Frank O]

A Kurt 6" certainly sounds like a nice vise to have. Not cheap if you go with the real thing, it appears. There seem to be any number of clones around, but I'd be concerned about the fit/finish, accuracy etc.

 

[mmcmdl]

" All thread " is your best friend when it comes to clamping .