Search found 172 matches

by arthur.marks
Wed Jun 11, 2014 1:42 pm
Forum: General Discussion
Topic: Counterboring to Precise Depth
Replies: 28
Views: 2039

Re: Counterboring to Precise Depth

D-bit? Do you have any properly sized drill rod or do you have the ability to harden O1? Basically you take a tool steel rod the diameter you want the counterbore recess. Cut with the side of an end mill to slightly less than 1/2 full diameter of the rod. Put about a 6-degree clearance angle across ...
by arthur.marks
Wed Jun 11, 2014 11:47 am
Forum: General Discussion
Topic: Counterboring to Precise Depth
Replies: 28
Views: 2039

Re: Counterboring to Precise Depth

Steve - are these counterbores for standard socket head cap screws (SHCS)? What is the screw size? Counterbores are usually bought and sized by the screw and not the counterbore diameter. Is this per chance for a 4mm metric screw or possibly a #8 machine screw?
by arthur.marks
Wed Jun 11, 2014 11:05 am
Forum: General Discussion
Topic: Counterboring to Precise Depth
Replies: 28
Views: 2039

Re: Counterboring to Precise Depth

That's certainly not a great way to measure a depth... I agree. Steve should use a stack of no less than grade AS1, as defined in US Standard B89.1.9, gage blocks recently calibrated and traceable to NIST on a calibrated, grade A as defined in Federal Specification GGG-P-463c, surface plate. A tent...
by arthur.marks
Tue Jun 10, 2014 3:06 pm
Forum: General Discussion
Topic: Counterboring to Precise Depth
Replies: 28
Views: 2039

Re: Counterboring to Precise Depth

RE measuring, is this where people tell me I should have gotten depth micrometers by now? Naw. Use the depthing rod on a good caliper. Alternately, mount a rod type dial indicator over the workpiece. Take a measurement on the top surface and one at the bottom of the counterbore. Subtract the figure...
by arthur.marks
Mon Jun 09, 2014 2:10 pm
Forum: General Discussion
Topic: Best Way to Fix Rusty Half Center?
Replies: 14
Views: 1473

Re: Best Way to Fix Rusty Half Center?

ctwo - none of them are truly ' half .' There is always some bit of fully round area on the end of the point. The amount depends on the size of the center (1MT, 2MT, 3MT, etc.); although, the 1 Morse size can get awfully small. For example, these half centers have a diminutive 3mm (~1/8") diameter c...
by arthur.marks
Mon Jun 09, 2014 10:57 am
Forum: General Discussion
Topic: Best Way to Fix Rusty Half Center?
Replies: 14
Views: 1473

Re: Best Way to Fix Rusty Half Center?

Steve - not sure if you received the half center with only the rotary table or if you bought a RT with tailstock. The half center is often needed for setups using the tailstock. It allows milling cutters to clear the end of shafts. For example, if you are milling a flat on the end of a shaft, the cu...
by arthur.marks
Mon May 12, 2014 12:31 pm
Forum: General Discussion
Topic: Are 5c collets tapered?
Replies: 3
Views: 717

Re: Are 5c collets tapered?

Bill is right. It should also be mentioned that the front, tapered section needs to be clamped if your size is to remain accurate after initial boring. I would recommend a simple collet block, insert a 5C emergency collet, tighten the locknut on the back of the collet block. The emergency collet wil...
by arthur.marks
Mon Apr 14, 2014 8:11 pm
Forum: General Discussion
Topic: Need a thread mic
Replies: 18
Views: 1691

Re: Need a thread mic

these: http://www.flexbar.com/shop/pc/P-D-CHECK-THREAD-WIRE-ATTACHMENT-SYSTEM-38p4735.htm are very helpful. They have enough flex to hold the two wires on the mic without constraining their movement. They easily space themselves correctly once the anvils are closed. If there is a question of the rea...
by arthur.marks
Thu Apr 10, 2014 10:30 am
Forum: Request For Services
Topic: Need quick milling job done (please help!)
Replies: 3
Views: 3292

Re: Need quick milling job done (please help!)

I work with lathes, I don't have any milling/drilling equipment. Set it up in a 4-jaw. Face each of the six sides using the cross-slide. Do careful layout with Dykem or a thick Sharpie marker. Scribe hole locations and center punch---this is all using hand tools. Chuck up the piece in the 4-jaw aga...
by arthur.marks
Fri Mar 28, 2014 8:33 pm
Forum: Lathes
Topic: Handy insert tool holder.
Replies: 14
Views: 1733

Re: Handy insert tool holder.

AT-10 long shank 1/2" version: http://www.aloris.com/store/index.php?route=product/product&product_id=923 AT-10S short shank 1/2" version: http://www.aloris.com/store/index.php?route=product/product&product_id=920&search=AT-10 They'll take a smaller size insert than your larger version, but they fun...