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rustydog
09-27-2012, 02:46 AM
I'm planning on refurbishing some old Brown and Sharp squares. It would include milling 1/16 stock douw to .050. I don't have a good way of holding thin material for milling and was looking at a magnetic chuck. I've never used a magnetic chuck. What attributes should be considered in selecting a new one. And same for used magnetic chucks. Any thoughts welcome.

winchman
09-27-2012, 02:55 AM
For a one-time deal, how about making your own magnetic chuck out of an automotive air conditioner compressor clutch? They're readily available at a low price, easy to modify, and very powerful.

http://www.world-trades.com/photo/583/6062/air-conditioner-clutch-539.jpg

The coil is shown upside down on the left. The rotor is on the right. You don't need the disk at the top.

You only need a 12-volt power supply that'll put out around three amps to run it. The clutch face is usually about five inches in diameter.


You might also use the magnet off of an electric trailer brake.

http://www.etrailer.com/merchant2/graphics/00000001/pics/B/P/BP01-110.jpg

oldtiffie
09-27-2012, 03:21 AM
Why mill it - 0.012"?

Why not grind it?

Rosco-P
09-27-2012, 08:17 AM
Magnetic chucks aren't meant for use on a mill. A little too much feed and/or DOC and the part goes flying. Either surface grind as oldtiffie suggests or use double sided carpet tape to hold it down and take very light cuts.

Jaakko Fagerlund
09-27-2012, 03:21 PM
Magnetic chucks aren't meant for use on a mill.
Depends on the chuck and the milling operation, but even heavy milling can be done if the part has enough (flat) surface for the magnet to adhere to. Been there, done that and a quick & easy solution for 5 axis work with preground parts.

Mcgyver
09-27-2012, 05:26 PM
I'm curious how you are planning on reconditioning them and what role the .050 stock plays? if you really do need .050" and don't have a grinder, consider buying whatever gauge plate is close to that. You're pretty much in the realm of sheet metal here

I've used a mag chuck in mill, use the stops take the lateral force and super light cuts. Like any clamping setup, things go wrong when the cutting force overcomes clamping force so super light cuts are the order of the day

Toolguy
09-27-2012, 07:30 PM
Also, small or thin parts need a fine pole magnet. A coarse pole magnet is for parts with a lot of thickness and surface area. "Small" and "a lot" are relative terms in this instance.

rustydog
09-27-2012, 09:05 PM
Thank you all for your feedback. I'm new to the forum and am very impressed with all the speedy help. I'd be pleased to hera any additional thoughts as well as suggestions on other ways to handle thin stock... THANKS AGAIIN TO ALL

rustydog
09-27-2012, 09:13 PM
I have a very small square head (I can't find my B&S catalog - must be on my nightstand) the name of which escapes me at the moment. It looks simular to ones used by die makers. The blade is missing. The slot in the head is .050 and I ordred Starrett 1/16 O1 ground stock from Enco as the closest fit. Once I redice the thickness I'll need to mill a 1/32 round bottom grouve down the center. Simular to most try squares but on a smaller scale. I've done enuf work wit a 1/8 cutter to be able to do some milling without breaking the cutter. The 1/32 cutter will be a new expperience - hopefully I've developed a good enuf feel to be able to do this cut successfully.

Always interested in critique and thoughts THANKS

rustydog
09-28-2012, 02:14 AM
I'm curious how you are planning on reconditioning them and what role the .050 stock plays? if you really do need .050" and don't have a grinder, consider buying whatever gauge plate is close to that. You're pretty much in the realm of sheet metal here

I've used a mag chuck in mill, use the stops take the lateral force and super light cuts. Like any clamping setup, things go wrong when the cutting force overcomes clamping force so super light cuts are the order of the day

========================
I have a very small square head (I can't find my B&S catalog - must be on my nightstand) the name of which escapes me at the moment. It looks simular to ones used by die makers. The blade is missing. The slot in the head is .050 and I ordred Starrett 1/16 O1 ground stock from Enco as the closest fit. Once I redice the thickness I'll need to mill a 1/32 round bottom grouve down the center. Simular to most try squares but on a smaller scale. I've done enuf work wit a 1/8 cutter to be able to do some milling without breaking the cutter. The 1/32 cutter will be a new expperience - hopefully I've developed a good enuf feel to be able to do this cut successfully.

Always interested in critique and thoughts THANKS

oldtiffie
09-28-2012, 03:42 AM
On these ie (both) of these (universal) tool and cutter grinders I can tilt the wheel such that its spindle is vertical and almost "fly-cut" the job similar to a Blanchard grinder using a "cup" or "saucer" wheel.

http://i200.photobucket.com/albums/aa294/oldtiffie/Surface%20and%20T-G%20grinders/Grind_work-head_demo9.jpg

http://i200.photobucket.com/albums/aa294/oldtiffie/Universal_grinder/Universal_grinder3.jpg

http://www.google.com.au/#hl=en&sugexp=les%3B&gs_nf=1&cp=13&gs_id=1q&xhr=t&q=blanchard+grinder&pf=p&output=search&sclient=psy-ab&rlz=1R2IRFC_enAU360&oq=blanchard+gri&gs_l=&pbx=1&bav=on.2,or.r_gc.r_pw.r_qf.&fp=42859130deccdb9f&biw=1280&bih=567

You simply cannot be too cautious or careful on a grinder.

Mcgyver
09-28-2012, 03:20 PM
========================
I have a very small square head (I can't find my B&S catalog - must be on my nightstand) the name of which escapes me at the moment. It looks simular to ones used by die makers. The blade is missing. The slot in the head is .050 and I ordred Starrett 1/16 O1 ground stock from Enco as the closest fit. Once I redice the thickness I'll need to mill a 1/32 round bottom grouve down the center. Simular to most try squares but on a smaller scale. I've done enuf work wit a 1/8 cutter to be able to do some milling without breaking the cutter. The 1/32 cutter will be a new expperience - hopefully I've developed a good enuf feel to be able to do this cut successfully.

Always interested in critique and thoughts THANKS

sounds like an interesting project.... I think i know the sq now and what you're doing.

Consider making some hold downs and just hold it in the vise. There's a bunch of BS in this thread but if you look toward the bottom of page 2 you'll see pics i put up what they are how they are used

http://bbs.homeshopmachinist.net/threads/54387-here-s-to-old-Bill-Hope/page2?highlight=holddown

because the piece you making isn't going to be very wide, I think this would work.

As for the groove, here's an idea: Take a round piece of HSS or tool steel. grind and stone a 1/32" radius on the bottom of it - like a form tool for the lathe. Mount and lock in the mill spindle and "shape" the groove with the part held by the hold downs and by moving the table to and fro

oldtiffie
09-28-2012, 08:25 PM
I have a very small square head (I can't find my B&S catalog - must be on my nightstand) the name of which escapes me at the moment. It looks simular to ones used by die makers. The blade is missing. The slot in the head is .050 and I ordred Starrett 1/16 O1 ground stock from Enco as the closest fit. Once I redice the thickness I'll need to mill a 1/32 round bottom grouve down the center. Simular to most try squares but on a smaller scale. I've done enuf work wit a 1/8 cutter to be able to do some milling without breaking the cutter. The 1/32 cutter will be a new expperience - hopefully I've developed a good enuf feel to be able to do this cut successfully.

Always interested in critique and thoughts THANKS

See my inadverdent reply at:
http://bbs.homeshopmachinist.net/threads/55912-Inch-by-inch-improving-my-surface-grinding-still-needs-improvement?p=798722#post798722