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7x10, 7x12, 7x14 Mini-Lathe Information

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WORKHOLDING AND TOOLHOLDING

This is fast becoming one of the more interesting areas of machining for me. When you first get started, chucking a workpiece in a vise is all it takes to machine your part. However, when you start getting into machining via CNC, it gets a bit more complicated (and more interesting)...

We've broken this section down further to include the following:

  1. Basic workholding (vises, blocks, clamps)
  2. CNC workholding (special jigs, fixtures, etc.)
  3. ER Collets (save your Z-axis travel)
  4. Mitee-Bite clamps (this company has some interesting clamping methods)
  5. Phase 2 Quick Change Tool Post (QCTP) (this is lathe-related)
  6. Rotary Tables (make your mill function like a lathe and more)

here is a screwless machinists vise. it has a 4.5" jaw opening and is a great size for the mini-mill.

this style doesn't have the series of holes in the sides which makes clamping flexible.

the first project was to make the clamps since there weren't step-clamps available.

the ends do not have slots as some other models do.

here's the bolt. it's a socket head 5/16" x 18TPI x 1.5" long with a cupped-type washer. the socket was stripped and the bolt needs to be replaced.

the pin is held by a small setscrew (not shown). you can therefore replace the pin as it gets worn.

here's the underside of the vise.

there are notches that the pin grabs onto.

You can even put these vises inside other vises to hold angles or work on complex parts. The 1-2-3 block is placed in the 2" screwless vise for scale.

vise-in-vise

here are some 1-2-3 blocks, parallels, v-blocks. these help support the workpiece.

i don't show step clamps since you probably have them already?

this is an adjustable v-block for setting angles up to 60 degrees.

when used with the screwless vise above, you're limited to only 1/2" or so grip surface so either buy a smaller one than this or get a vise with taller blocks.

these are precision v-blocks.

for an import (purchased through J&L industrial - a great first time shopping experience, give them a call and tell them to lower their prices - see what happens!), these are very good quality and even came in a nicely built wooden case.

now, it should be easier to mount leadscrews for machining.

step blocks (the full set is not pictured.) these are useful for holding onto material. (pretend the vise is the workpiece). how do you use it? click here.
these are Kant-Twist clamps. way better than the usual C-clamp. easy to use and they have wide jaw openings for their size.

For those of you moving up the mill chain, you may soon find yourself wanting a larger vise, something that's 6" wide and has a substantially large opening on the order of approximately 8". If this is the case (when you get a 700lb. round column/dovetail mill like the ZAY7045/RF-45 or even a Bridgeport or clone full-size knee/turret mill), you'll want to start with something like the Kurt D675 6" vise. The D675 is the staple of many machine shops' workholding tooling. Recently, the D675 has been upstaged by the D688 which has a few more features like a larger opening and more workholding pressureas the "groovelock jaw" which is essentially just a slot cut through the top of the base jaw. Both have recently again been upstaged by the D810 which is based on a new body style from the D600 series.

Here's a quick comparison of features as mentioned from the Kurt Workholding website:

D675 D688 D810

The D675 has a new vise body with four major improvements:

  • Powder coat paint resists peeling.
  • Machined rail allows precision alignment.
  • A 7-1/2" jaw opening.
  • Stationary jaw features an integral key and larger fasteners that reduces deflection by 50%.

Bed height matched to size 2.875" (73.025mm) ±0.0005". Patented “O” ring pull down feature is standard. Parts from the previous body style are interchangeable with this new one.

  • Large 8.8 inch jaw opening.
  • Outside rail edges of the body are machined.
  • Vise nut does not extend beyond the end of the vise body.
  • D688 has the same footprint as the D675 vise. Distance from keyway to stationary same as D675.
  • Groove Lock jaw (D60-315) and workstop (WSRL46) standard.
  • Patented “O” ring pull down feature standard.
  • Approximately a 20% increase in clamping pressure over D675 vise.
  • Distinctive patented design of the “Kurt Look”.
  • Patented AngLock design.
  • Bed height matched to size 2.875" (73.025 mm) ±0.0005".
  • Repeatability within 0.001".
  • Sealed needle thrust bearing used at hex end of screw to reduce clamping friction.

Kurt’s new D810 features a new updated body style:

  • Top down, four bolt design on the stationary jaw reduces vise deflection by 25 percent while allowing total disassembly of the vise without removing the body from the machine table. Special brush seals shield and protect vise screw threads from machined chips and residue.
  • The nut has been shortened so as not to protrude past the end of the vise body. New powder coat paint finish resists coolant-induced peeling for greater corrosion protection. The overall vise footprint is identical to earlier models so both can be used interchangeably and in tandem.
  • With a jaw opening of 10 inches and clamping force up to 11,600 lbs., the D810 vise locks parts precisely including very large parts for aggressive “hogging out” operations.

With the D675 retailing at over $500, you can find them for roughly $300. If you check eBay and watch the shipping costs (remember that ENCO may or may not ship such a heavy item with their free shipping coupon - check first), you could end up a new vise saving nearly 40% off or better.

d675-x2

Just how large are these vises? As you can see above, we've placed the mini-mill spindle/head unit in the D675. Weighing in at nearly 80 lbs., it's not a trivial move off the table to the workbench and vise versa.

If you receive the ENCO Hot Deals catalog, you'll see a competitor's vise made from a company called Parlec. While the company is located in the USA, the actual vise is made in Taiwan. Given that Taiwanese machinery and tooling is generally of higher quality than those made in Mainland China and even moreso than items made in India, we wouldn't be too concerned with their vise. They even guarantee precision on par with the Kurt's. Specs from the ENCO website reveal the following about the Parlec PWS-6900 vise:

6 In. Vise with 9 In. Opening Type: Milling Machine Vise Jaw Width: 6.0000 In., 6 Jaw Height: 1.735 In. Jaw Opening: 8.8 In. Width: 8-3/4 Overall Length: 16.8100 In. 
Type: Milling Machine Vise
Jaw Width (Decimal Inch): 6.0000"
Jaw Width (Inch): 6
Jaw Height (Decimal Inch): 1.7350"
Jaw Opening (Decimal Inch): 8.8000"
Width (Inch): 8-3/4
Overall Length (Decimal Inch): 16.8100"
Height (Decimal Inch): 4.3600"
Base Length (Decimal Inch): 16.8100"
Base Width (Inch): 8-3/4
Base Width (Decimal Inch): 8.7500"
Clamp Capacity pounds: 7,968
Manufacturer Part Number: PWS-6900

This model is comparable to the D688 given its jaw opening and slotted base/fixed jaw. At a retail price of $502.87 and a sale price of $375.95 (truck freight only - no UPS free shipping here), it may be worth looking at. Comparing this price to the D675 also from ENCO with a non-sale price of $463.05 and a sale price of "only" $398.00, the Parlec is giving Kurt a run for its money. But, if you want a true made in the USA piece of precision cast iron, the Kurt D675 is the way to get started. And apparently it does ship UPS ground!

Comparison specs from the ENCO website for the Kurt D675 vise:

6" W 7 1/2" JAW CAPA KURT ANGLOCK PRECISION VISE 
Type: Anglock and Positive Locking Vise
Jaw Width (Decimal Inch): 6.0000"
Jaw Width (Inch): 6
Jaw Height (Inch): 1-1/2
Jaw Opening (Decimal Inch): 7.5000"
Jaw Opening (Inch): 7-1/2
Width (Inch): 6
Overall Length (Inch): 16-3/4
Overall Length (Decimal Inch): 18.7500"
Height (Decimal Inch): 4.6100"
Clamp Capacity pounds: 6721
Manufacturer Part Number: D675
 

See more pictures and read more commentary on the Kurt D675.

 

 

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