The Sherline Miniature Machinist's Newsletter
As noted in a previous
e-mail, Sherlineís owner, Joe Martin passed away
New Product Spotlight
ï P/N 1205 Adjustable Bullnose Live Center: $95.00
One of the engineering compromises inherent in a lathe design that offers the versatility of a headstock that can be rotated to turn tapers is that even with a precision ground alignment key it can still contain enough part tolerance buildup to allow a slight misalignment of the headstock and tailstock. Factory settings call for .003" or better alignment, but some jobs require even better alignment. Due to customer requests, we have added a second live center to the adjustable tailstock tool line for use primarily with tubing.
How the adjustable tools work
These tools allow for perfect alignment between headstock and tailstock. A rear plate with a #0 Morse taper for the tailstock spindle is attached to a front plate holding the tool, or in this case the bullnose live center running in two preloaded ball bearings. Slightly oversize holes in the rear plate allow enough adjustment of the front plate to bring it into perfect alignment with the headstock. Once adjusted, scribed witness marks placed at the top of the plates allow the accessory to be returned to the same position in the tailstock spindle the next time, and the tool will remain in alignment.
The P/N 1201 standard live center has a 60∞ point that locates in a hole drilled by a center drill in the end of solid stock. The P/N 1205 bullnose live center can support parts or tubing with larger center holes between 5/16" and 1-3/4" inside diameter. For those of you working on tubing and needing highly accurate centering, the P/N 1205 is Sherlineís solution.
Shop Tip of the Month
Using the Parting Tool/Fred Smittle
†Parting off a cannon barrel with the P/N 3002 cutoff tool holder.
Before discussing using the parting tool letís get the blade ready. First of all, the parting tool must be sharp, and the cutting edge should be square with the blade. The clearance below (relief angle) should be five to fifteen degrees.† If you hold the blade above the grinding wheel centerline while sharpening it the clearance will be generated automatically.† When using the tool on the lathe there are several basic rules:
†††††††††† ï The cutting tip must be on vertical center line of the part
††††††††††† ï The tool must be square with the work
††††††††††† ï The tool should not extend from the holder any more than is needed.
††††††††††† ï The part should not be held between centers.
††††††††††† ï Use plenty of cutting fluid.
††††††††††† ï Use a slow cutting speed.
Standard P/N 3002 cut-off tool holder. Note that the blade is angled upward providing a positive rake and so that center height can be adjusted.
When using the standard parting tool holder (P/N 3002) there is no control over the length it is extended because of the built-in positive rake.† This is why the cutting edge must be ground square. If it is at an angle the blade will tend to deflect sideways.
The tool must be square with the work. You can locate the blade against the chuck face and then tighten the screw holding the toolpost. If that can't be done, pick a point on the workpiece and locate the blade slightly to the right of that point. While watching the space between the blade and the part, move the crosslide in and out at least 3/4".† If the gap remains the same the blade is square. If is gets wider as you move the crosslide away from you the blade is pointing to the left.† If the blade is pointing to the right the gap will get smaller as you move the crosslide away from you.
The blade must be extended far enough to be at the vertical centerline. Now you are ready to part off your work.† Be sure the work is held securely and move the blade over so it is cutting very close to the chuck.† Do not try to part something that is supported with a live center. Turn on the lathe and adjust the speed to half of the normal turning speed.† Use a cutting fluid and feed the blade into the part. You should see the chips roll up and come back out. If they don't come out and start to pile up in the groove, back the tool out to clear the groove.† Keep the blade wet with cutting fluid.
†P/N 3018 Rear mount cut-off tool holder. Note that the blade is upside down, parallel to the table and pre-set to the proper height, allowing for in/out adjustment.
If you have the P/N 3018 Rear Mount Parting Tool life is a little easier. The blade is at a neutral rake angle and needs only to stick out far enough to part the work. The toolpost is set on the left back side of the crosslide, the cutting tool is mounted upside down and squared with the work.† The vertical centerline is already set by the toolpost. When ready to part off, the blade is brought forward into the work and gravity helps the chips fall downward because the blade is inverted. This makes turning multiple parts easier because the turning tool can remain in place on the back side of the crosslide while other operations are done with a regular tool post on the front side of the part.
See the Sherline TIPS page for more useful machine shop tips. If you have a useful tip from your Sherline shop that you would like published, please send photos and a written description to firstname.lastname@example.org.
†This depth stop was featured in the March, 2012 newsletter. It was designed by Tracy Atkinson.
Send us your Sherline Workshop Project Photos
If you have completed a project on your Sherline tools that you would like to share with other Sherline users, send photos and a description to email@example.com. Include photos of setups if you have them. We will publish customer projects in future editions of the newsletter and include the best ones in the Workshop page on the Sherline web site.
Did you know?
ï Ordering a small amount of metal from a major metal supplier is not practical. They want to sell you 12-foot bars and charge a big fee to cut one down. Metal from a scrap yard may not be properly marked and it can be hard to tell what you are getting. Metal and plastic raw materials †can be ordered on-line in short lengths with no cutting charges. See our page on raw materials for a list of suppliers at www.sherline.com/online.htm.
ï.Not sure what various parts of your Sherline tools are called when trying to describe parts you need? See the Sherline Termiology page for help so weíre all speaking the same language.
Upcoming Model Engineering Shows
ï April 11-13, 2014ó18th Annual Cabin Fever Expo Model Engineering Show & Auctions in the Utz Arena (Formerly Toyota Arena), York Fairgrounds & Expo Center, York, PA 17404
ï April 26-27, 2014óNorth American Model Engineering Society (NAMES) Expo, Wyandotte, MI. Sherline will have a booth there and the Joe Martin Foundation will present its annual award to Metalworking Craftsman of the Year during the show. See www.namesexposition.com for details.
(Send us your show information and we will post it here.)
Joe Martin Craftsmanship Foundation News
Craftsman of the Year Award Winner Announcedó
ï A six-foot long model of the Cyclone
Racer roller coaster from the old Long Beach Pike amusement park was
donated by Don Woods. The model was built by his late cousin Richard Docken who
was a roller coaster fanatic all his life. The original was built in 1930 and
torn down in 1968 to make way for
ï Lou Chenotís 1/6 scale Duesenberg is now on permanent display in the museum. Just added to enhance the exhibit is a display of some of the tire molds, wooden fender bucks, special tools and spare parts made during the construction of the model.
New Craftsmen Added to the Online Museum ó
Groups Visiting the
ï Museum VolunteersóAnyone interested in joining the museum staff as a docent (guide) or volunteer machinist in the machine shop, please contact firstname.lastname@example.org or call 760-727-5857 and ask for Craig.
ï Getting your projects displayed in the museumóIf you have built a project you feel is worthy of display in the museum, contact Craig to learn about displaying your items on loan or tax deductible permanent donations of your work.
ï Construction UpdateóDue to pipeline installation, traffic to the
museum on Lionshead is currently one way westbound on Lionshead starting at