Cobra 4...presser Foot Marking Leather

[bushpilotmexico]

Hi everyone,

Still practicing with my Cobra 4, getting reasonably competent with most sewing but now it's time to close down a couple of holsters and sew the welts in.

I made up a test piece just to practice with and you can see the presser foot is leaving an imprint on the leather.

If I hadn't dyed my actual holster leather before hand and was just dealing with the leather you see in the photos I could probably using some water and burnish the marks out.

My problem now is that I have dyed the holsters and I'm going to see the track of the presser foot after I am finished.

Any suggestions as to how to prevent it?

[JLSleather]

Is your holster really that thick?#@!@#!@#$!!

There's a few ways to git around that if ya hafta. Simplest one is to make the holster 1/2" wider at the stitch line, stitch it up, then trim off the marks from the feet.

Beyond that, a fella could move a couple bolts --- but I hate to be crowding the guy who "stands behind" those, so I'll let him answer that.

[Colt W Knight]

Hi everyone,

Still practicing with my Cobra 4, getting reasonably competent with most sewing but now it's time to close down a couple of holsters and sew the welts in.

I made up a test piece just to practice with and you can see the presser foot is leaving an imprint on the leather.

If I hadn't dyed my actual holster leather before hand and was just dealing with the leather you see in the photos I could probably using some water and burnish the marks out.

My problem now is that I have dyed the holsters and I'm going to see the track of the presser foot after I am finished.

Any suggestions as to how to prevent it?

I wish my machine sewed that thick.

I am sure the folks who work with those big machines can help you reduce the marks, but I don't think anything will sew that much leather and leave no marks at all.

The teeth were ground off my smaller machine, and it still leaves some marks.

Edited October 9, 2015 by Colt W Knight

[Red Cent]

I never use a welt in my holsters. No matter, I still get tracks. I don't think we can get rid of all the marks. Wet down the leather real good and flex the leather. It will stretch a lot of the marks out of the leather. May not do it with 3/4" of leather tho.

[Wizcrafts]

There is either a sharp edge on the presser foot, or it is tilted up one way or the other. I would expect to see a smooth tract that is the width of the outside toes, but not those stab wounds. Remove the outside foot and feel it to see if there is a sharp edge. Use Emory cloth to smooth out the offending edge and polish it on a buffing wheel with green rouge.

If the foot has too much slack on the presser bar, it might shift up or down from true horizontal.

[bushpilotmexico]

I never use a welt in my holsters. No matter, I still get tracks. I don't think we can get rid of all the marks. Wet down the leather real good and flex the leather. It will stretch a lot of the marks out of the leather. May not do it with 3/4" of leather tho.

I was hoping I wouldn't have to wet the leather down but I guess if I do I will have to give the whole holster a dip because it's already dyed and if I just sprayed the stitching line and burnished I think I would get a water stain.

I know the samples that Steve sent with the machine showed presser marks, especially the chunk that was 7/8" thick.

I was kind of wondering if I could use a couple of layers of that green or blue painters tape and lay it along the path of the presser foot, might soften the blow? I'll experiment a little bit.

I know from Googling I found out that if you start off 6 stitches per inch as the leather thickness increases so does the tension and you'll have 8 stitches to the inch at the top.

On my third line once I started to sew up hill I manually increased the stitch length one full turn and the stitch length proved to be fairly consistent through out.

[Wizcrafts]

I was hoping I wouldn't have to wet the leather down but I guess if I do I will have to give the whole holster a dip because it's already dyed and if I just sprayed the stitching line and burnished I think I would get a water stain.

I know the samples that Steve sent with the machine showed presser marks, especially the chunk that was 7/8" thick.

I was kind of wondering if I could use a couple of layers of that green or blue painters tape and lay it along the path of the presser foot, might soften the blow? I'll experiment a little bit.

I know from Googling I found out that if you start off 6 stitches per inch as the leather thickness increases so does the tension and you'll have 8 stitches to the inch at the top.

On my third line once I started to sew up hill I manually increased the stitch length one full turn and the stitch length proved to be fairly consistent through out.

The change in stitch length is due to the pendulum effect of the needle bar pivoting from the top of the machine head. The longer the needlebar and needle combination, the greater the loss of stitch length as the thickness increases.

One other workaround is to sew these projects on a Campbell Randall or Union Lockstitch machine.

Edited October 9, 2015 by Wizcrafts

[Colt W Knight]

The change in stitch length is due to the pendulum effect of the needle bar pivoting from the top of the machine head. The longer the needlebar and needle combination, the greater the loss of stitch length as the thickness increases.

One other workaround is to sew these projects on a Campbell Randall or Union Lockstitch machine.

How much do those cost?

[Wizcrafts]

How much do those cost?

The Union Lockstitch sells for about $5,000 and the Campbell Randall for about $6000, base price. Accessories will drive the cost up considerably. I have owned two Union Lockstitch machines over my career as a leathercrafter. Like a fool, I sold them.

These machines have square drive.

[Art]

Campbell, $4k Used to $6k New with accessories. Union Locks are all over the place (price wise) depending on condition. Unions are nice machines, but more of a factory item where there is a maintenance staff. Wiz knows the UL pretty well, but there is no substitute for hands on experience. Campbells are a little less of a maintenance problem, but you would be wise to leave them setup for whatever you do the most of and not fiddle with them.

Art

[JLSleather]

The change in stitch length is due to the pendulum effect of the needle bar pivoting from the top of the machine head. The longer the needlebar and needle combination, the greater the loss of stitch length as the thickness increases.

[Evo160K]

My wife was reading this thread and commented on the thickness of the leather.

She's wondering if a damp cloth and an iron (or steam) would remove the marks, like on wood?

[dikman]

It would probably remove the marks, but I suspect it could have some "interesting" effects on the dye.

[Uwe]

That is a pretty strong wedge shape, looks like a door stop!

A couple things come to mind:

You may have to adjust foot pressure spring as you change to the thicker part. As the material gets thicker, the spring probably gets compressed more and puts more force on the leather surface.

Those marks look like high heel marks on a wood floor, change the footwear and make sure it sits flat. Try using a presser foot with a larger bottom surface to distribute the pressure and make sure it sits flat on the top surface of the leather. It may heel or toe into the leather because you're walking a relatively steep grade downhill or uphill. The top surface of the leather is never quite parallel to the needle plate or the bottom of the presser feet with a wedge like that. Build a "ramp" attachment to compensate for the wedge shape of your work piece and make the top surface level.

Is that a test piece or an actual part you need to produce? If it's just a test piece, the problem may disappear if you sew a actual work piece with constant thickness (or just the occasional step up or down) and parallel surfaces rather than a continuous wedge shape.

[Big Sioux Saddlery]

Uwe nailed it. It's the steep uphill/downhill that is at least in part responsible for the marks. I see it in harness construction such as breeching ends where I go from 2 layers thick to 5 at the very end. Even with careful skiving, there's going to be an increase in thickness. Sewing uphill is worse than downhill for leaving marks. Backing off the downward tension on the presser foot when you come to material as thick as shown in your pics usually results in dropped stitches, at least for me. Going through that much material needs a lot of pressure on the foot. I rub out what I can, and just have to live with what's left. Not to say that some filing on the foot couldn't help.

[TinkerTailor]

Run an embossing wheel over the marks and make it look like you meant it.

[Colt W Knight]

Run an embossing wheel over the marks and make it look like you meant it.

IS that like a roller, or more like an English wheel?

[TinkerTailor]

I have seen them as a hand tool much like a stitch marking wheel but with an embossing pattern.

[bushpilotmexico]

I appreciate all the replies. I sewed that test piece with a left toe presser foot and a lot of weight is on the single foot. My nephews wife's father is a saddle maker and he suggested that I try using the double toe foot. I did today and because the weight is being distributed between the two feet there is considerably less indentations.

On the test piece earlier I dampened the leather, burnished and they all disappeared. Vic the saddle maker said that considering the leather is pre-dyed just to dampen the leather along the stitch line taking in any presser toe marks and then burnish. Vic said that even if the leather picks up a water stain it might even compliment the holster when finished.

[Red Cent]

Colt, you can buy different wheels that will fit your stitching wheel hand tool.

http://www.ebay.com/itm/like/400388832912?catId=14339&item=400388832912&mid=446528&sortbid=20&rmvSB=true

[TinkerTailor]

Colt, you can buy different wheels that will fit your stitching wheel hand tool.

http://www.ebay.com/itm/like/400388832912?catId=14339&item=400388832912&mid=446528&sortbid=20&rmvSB=true

Bingo. These are definitely on the want but don't need list. Now to find a project that needs them.....

[billybopp]

I have a set of embossing wheels that I use for trim around some items. They do a nice job.

Bill