Lever Action Clamping Screws

My 3” swing Unimat SL lathe, 7” swing mini lathe and 12” swing geared-head lathe all use various clamping and locking screws with M6-1 threads. I replaced the M6 cap head socket screws with my version of clamping screws and some with a swing-out levers to apply more torque. The swing-out levers eliminate using Allen wrenches.

The clamping screws were machined from 3/8” dia. 1018 CRS bar, the M6 threads cut with a tailstock mounted die, and the knurl is 21 pitch (whereby the 3/8” dia. was reduced to 0.364 before knurling). Some of the clamping screws have brass inserts at the screw tips to prevent marring the taper gibs on the lathe cross side and compound.

The length of the clamping screws vary. The two screws for the mini-lathe change gear cover are 2.5” long. The Unimat headstock and milling head spindle slide clamping screws are 2” long and the drilling/milling conversion clamping screw is 1.1” (including brass tip). The 12” swing lathe compound locking screw is 1.1” (including brass tip) and the cross slide locking screw is 2.2” (including brass tip). The cross slide screw is longer than needed because it will be moved to the other side when this threaded hole is covered by the cross slide DRO sensor rail. All the parts were sprayed with Boeshield T-9 rust and corrosion prevention to keep the degreased surfaces from rusting.

The swing out levers are 0.062” x 0.365” x 1.20” and hand finished with 3/16” end radii starting with 1/16” steel support rails salvaged from electronics rack panels. The slots in the clamping screw heads are 0.063” wide by 0.450” deep. The levers are retained with 3/32” roll pins shortened to fit. Finding the 1/16” thick steel was the hardest part of this project because most CRS bar stock are 1/8” or thicker.

Very nice Paul. The knurls are clean.

Beautiful work, and nice detail on those pictures too. :)

Thank you, Randy and DIYer,

These were easy to make and even easier to use. I made a fixture for holding the knurled screw head for the slot cutting work. There is a M8 cap screw for locking in place the shorter M6 clamping screws and a hex nut for locking in place the longer versions. Here are some photos.

Regards, Paul

Thanks Paul! We've added your Lever Action Clamping Screws to our Lathe Accessories category, as well as to your builder page: Paul Jones' Homemade Tools. Your receipt:

<div id="blocks"> <div class="block b1 pngfix"> <div class="bimg"> <div> <a href="http://www.homemadetools.net/lever-action-clamping-screws"><img src="http://www.homemadetools.net/uploads/134022/lever-action-clamping-screws.jpeg" /></a></div> </div> <div class="head pngfix"></div> <div class="left pngfix"></div> <div class="right pngfix"></div> <div class="blockover b1 pngfix"> <div class="title"> <a href="http://www.homemadetools.net/lever-action-clamping-screws">Lever Action Clamping Screws</a> <span> by <a href="/builder/Paul+Jones">Paul Jones</a></span> </div> <div class="tags">tags: <a href="http://www.homemadetools.net/tag/lathe">lathe</a>, <a href="http://www.homemadetools.net/tag/clamp">clamp</a>, <a href="http://www.homemadetools.net/tag/knurling">knurling</a>, <a href="http://www.homemadetools.net/tag/lever">lever</a></div> </div> </div> </div>

Thanks Paul! We've added your Screw Slotting Fixture to our Miscellaneous category, as well as to your builder page: Paul Jones' Homemade Tools. Your receipt:

<div id="blocks"> <div class="block b1 pngfix"> <div class="bimg"> <div> <a href="http://www.homemadetools.net/screw-slotting-fixture"><img src="http://www.homemadetools.net/uploads/134026/screw-slotting-fixture.jpeg" /></a></div> </div> <div class="head pngfix"></div> <div class="left pngfix"></div> <div class="right pngfix"></div> <div class="blockover b1 pngfix"> <div class="title"> <a href="http://www.homemadetools.net/screw-slotting-fixture">Screw Slotting Fixture</a> <span> by <a href="/builder/Paul+Jones">Paul Jones</a></span> </div> <div class="tags">tags: <a href="http://www.homemadetools.net/tag/knurling">knurling</a>, <a href="http://www.homemadetools.net/tag/fixture">fixture</a></div> </div> </div> </div>

Hi Paul, very nice job !
I see you are using your lever screws on the sides of the dovetails of your slides. I suppose it is for pressing the wedges that serve to reduce the play in the dovetail ?
This is something that I have a lot of difficulty to setup on my Chinese lathe.
You seem to have one single screw for that where I have several little set screws (so tiny head that they will end up to be worn sooner or later), and they are locked using a slim nut.

I feel my slides are whether too loose, and I have vibrations or even worse, I sometime see the tip of my cutting tool rolling under the piece .... Or I have them too tight, so with no play, but the cranks become difficult to turn ...

Could you provide an advice on how to setup properly these screws ? Maybe I should replace them right now by scews with heads or knurled buttons like you.

I don't see any locking nut on your screws ? no need for that ?

Thanks in advance !
Christophe

Christophe,

The compound and cross slide on my 12" swing lathe use tapered gibs. The gib is wedge-shaped and adjusted by loosening or tightening an adjustment screw located on the end of the gib and not on the side. The lever action locking screws gently push on the side of the tapered gib and add some sliding resistance. It takes just a fraction of a turn to lock the tapered gibs. I keep the compound locked down in normal operation and the cross slide is almost never locked. The tapered gibs are very easy to adjust and are an excellent design feature but more expensive to manufacture.

I think the gibs on your lathe are similar to what I have on my 7" swing mini lathe. I bought my mini lathe in 1993 and this one was made in Taiwan but looks just like the Chinese designs. The mini has three set screws along the edges of the compound and cross slide for adjusting a flat gib (not tapered) with a rhomboid cross section. I honed these gibs to be very smooth and flat, and enlarged the shallow dimples where the side adjusting set screws rest. It took a lot of work but the mini lathe compound and cross slide run very smoothly. There is a fourth screw used as the locking screws and I plan to replace these smaller diameter metric hex head cap screws with my lever action locking screw. It will probably be an M5 and not M6. I provided a photo for clarity and will post the changes at a later date.

I hope this helps with your question.

Thank you for asking, Paul

Thanks Paul for the great write up and pics. Looks like you went into production there! :cool: Pretty handy and good ideas for all the uses. Knurling is real clean and looks like you might have used my knurl calc based on the number I saw. I do those brass tips sometimes too and curious of your method of inserting them...thread or sliding/press fit with LT603? For mine I have a bit of a rule of thumb...the smaller screws I tend toward press in, larger screws - thread them, but not hard and fast based on the application. Nice fit and finish to yours! Also a Big Fan of Boeshield products! Great Mods! ~PJ

Hi Christophe. Thought I might chime in here as well, as I think we have similar issues and peanut Sieg's. It has always been a constant vigil to keep the all the gibs adjusted properly for me. I personally started out with the LMS procedure. It's kind of an art and feel but you get faster after about 20 times.

The "Roll Under" you speak of is likely caused by the Carriage retainer slides. You can also use the LMS procedure for that, but I added a bit of blue Locktite (242) to each of the screws prior to adjustment. It has helped tremendously on the frequency of adjustment. Also by sliding the carriage the full length of the ways while adjusting. My old bed is worn more toward the chuck so I adjust them so the are snug there and will barely pull off the end of the ways.

There are lots of reasons for the constant vigil but primarily it's the Gib material (beer cans), IMHO. I will be making a custom set from Silicon Bronze for my new bed and extended cross slide. It's harder, provides good lubricity and won't tend to distort so easily from repeated adjustments...although I'm hoping to minimize that too with all my hand work to get them square, parallel and perpendicular with better tolerances over all. Again the material on a $500 lathe is not so good so it won't solve every thing. I have seen some YT DIY Turcite applications which might eliminate some of that...but it's still a $500 lathe with $5k in labor. ~¿@

Hope this helps! ~PJ

Yes, I went hog wild on what started out as just two simple clamping screws for mini lathe change gear cover. It was so easy to make these that I started looking around the shop and thought about adding the levers for the next set. That led to making the improved slotting saw arbor for the Unimat, then the slotting fixtures, and then more clamping screws, and I am not done yet.

I used your knurling calculator to double check my calculations. I keep several spiral bound notebooks with green colored grid paper in my shop for my notes and pencil hand drawings. I keep a set of notes for knurl diameters that work well so I don't have to recalculate. I use an import scissor knurling tool from Enco that I have "improved". I would change the knurls to a finer knurl pitch if I could get the bearing pins out. Any suggestions from the readers would be appreciated.

All the brass tips are press fits and secured with Loctite 680 for good measure. In this case I used a 0.124" reamer X 0.30" deep in the screw tips before parting-off the completed part in the lathe. In case I forget this step, I can use a special chuck with the toolmaker mini jaws to hold the screws ( Homemade Mini Toolmaker's Jaws ). Probably the most important dimension is the OD of the brass tip so it doesn't mushroom into the bottom of the holes. I make these 0.05" smaller in diameter than the minor thread diameter. The Loctite helps in retaining the tip. Like in the oil drilling business, never want to loose a tool down the hole.

The Boeshield is expensive but the can lasts forever. I used Boeshield this time because when I removed the two clamping screws from the mini lathe for the group photo, I noticed the exposed tops were starting to rust as compared to the original photo taken a month earlier. I think it is because of the degreaser. I use Zep 505 spray degreaser on a rag to remove the lubrication oil from the oily knurled parts while the parts are still in the lathe. I want to see the knurls and determine if I need a second pass. I find that first lightly hand tightening the scissor knurling tool to verify the knurl tracks are tracking, and then using a wrench to further tighten another one-third turn usually produces a very clean knurl in one pass.

PJs thanks for asking,

Regards, Paul Jones

Thanks for all the info Paul! It's fun and frustrating to have to make a tool to make a part or another tool but do get the "I'm on a role now" feeling...fun!! I ran out of my small bottle of 680 a year or so ago but still have a big bottle of 603. Definitely a bit stronger in shear and better gap fill. Wish I had a set of reamers!! Good point on being under the minor by a skosh for the tips. Saw those tool maker jaws a while back and Really like them...been on my long list of todo's since.

Not sure of any method to get those pins out other than a press. Also check that both ends are the same diameter...seen some that have a slightly larger shoulder on one side that presses in (directional). Might try a heat gun for a few minutes and then use a pin punch and ball peen? On my inexpensive LMS one I use E-clips and made some new pins from O1 and hardened...much better than the originals...no galling yet either! Your Enco's have a lot more spizeringtom than the LMS with their finer thread and cone...would be great to do a single pass knurl! Thanks! ~PJ

While most of this conversation is above my pay grade, pjs said it. Heat gun (or propane) to defeat the loctite then use a punch and a ball pein. Acetone and vegetable oil 50/50 makes a good penatrating oil to use with heat, when dealing with rust and thread lock too.

jere,

Thank you for the advice for freeing the pins used to hold the knurls. I will definitely try the homemade penetrating oil. I remember seeing many comments about the benefits of this type of formula on HomemadeTools at http://www.homemadetools.net/forum/h...rating-oil-159 . Looks like a real winner.

Thanks, Paul

Nice job. What kind of knurler did you use ?

Hi Aphilipmarcou,

Thank you for the compliment. I use an import scissor-type clamp-on knurling tool that bought from Enco years ago and have modified and improved it by removing all the "slop" out of the tool. I also added a feature that makes it easier to tighten the knurling tool by hand and most of the time do not need to use a wrench to tighten the knurling tool (see http://www.homemadetools.net/forum/k...7860#post24656 ). Using the feel by hand makes for more consistent knurling when using around 150 to 240 RPM and a feed rate of 0.008" IPR and plenty of lubrication (not cutting) oil when working with 303 stainless steel. It usually takes two passes, one to the left and a return to the right to produce a sharp knurl.

A good example is some of the kitchen tools I made (see http://www.homemadetools.net/forum/s...3072#post77395 ). I also use a brass brush along the top knurling wheel to remove any flakes of steel that sometimes come off from the knurling process and this prevents the flakes from being embedded back into the surface finish. I always pre-machine the part diameters to the correct diameter dimension by calculating this by hand or using the Android phone app "Knurling Calculator" and typically make the part 0.001" to 0.002" larger than the suggested diameter. It is better to be slightly larger on the diameter than smaller.

I hope this helps to explain the knurling process I use on steels. The most difficult knurling for me is when working with brass and the best advice is to use a flood coolant or a Noga Cool Mist system to quickly remove the brass flakes produced when knurling brass.

Regards,

Paul Jones

Quote:

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Originally Posted by Paul Jones

Hi Aphilipmarcou,

Thank you for the compliment. I use an import scissor-type clamp-on knurling tool that bought from Enco years ago and have modified and improved it by removing all the "slop" out of the tool. I also added a feature that makes it easier to tighten the knurling tool by hand and most of the time do not need to use a wrench to tighten the knurling tool (see http://www.homemadetools.net/forum/k...7860#post24656 ). Using the feel by hand makes for more consistent knurling when using around 150 to 240 RPM and a feed rate of 0.008" IPR and plenty of lubrication (not cutting) oil when working with 303 stainless steel. It usually takes two passes, one to the left and a return to the right to produce a sharp knurl.

A good example is some of the kitchen tools I made (see http://www.homemadetools.net/forum/s...3072#post77395 ). I also use a brass brush along the top knurling wheel to remove any flakes of steel that sometimes come off from the knurling process and this prevents the flakes from being embedded back into the surface finish. I always pre-machine the part diameters to the correct diameter dimension by calculating this by hand or using the Android phone app "Knurling Calculator" and typically make the part 0.001" to 0.002" larger than the suggested diameter. It is better to be slightly larger on the diameter than smaller.

I hope this helps to explain the knurling process I use on steels. The most difficult knurling for me is when working with brass and the best advice is to use a flood coolant or a Noga Cool Mist system to quickly remove the brass flakes produced when knurling brass.

Regards,

Paul Jones

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Many thanks for A LOT of useful information there, Paul.